{"id":628,"date":"2022-12-30T07:56:10","date_gmt":"2022-12-30T07:56:10","guid":{"rendered":"http:\/\/www.gislxz.com\/?p=628"},"modified":"2025-08-23T11:41:48","modified_gmt":"2025-08-23T11:41:48","slug":"java%e5%9f%ba%e7%a1%80%ef%bc%882%ef%bc%89","status":"publish","type":"post","link":"https:\/\/www.gislxz.com\/index.php\/2022\/12\/30\/java%e5%9f%ba%e7%a1%80%ef%bc%882%ef%bc%89\/","title":{"rendered":"Java\u57fa\u7840\uff082\uff09"},"content":{"rendered":"\n

java\u57fa\u7840\uff081\uff09\u88ab\u6211\u4e0d\u5c0f\u5fc3\u5220\u4e86\u3002\u3002\u3002\u8fd8\u597d\u7559\u4e86\u4e2a\u5907\u4efd\uff0c\u4f46\u662f\u548c\u73b0\u5728\u7684\u51b2\u7a81\u4e86\uff0c\u53ea\u80fd\u7559\u4e2a\u56fe\u7247<\/p>\n\n\n\n

https:\/\/43.128.46.201:8888\/down\/kVbDnSFrjPF2.jpeg<\/a><\/p>\n\n\n\n

\u5305\u88c5\u7c7b<\/h2>\n\n\n\n

\u5176\u5b9e\u5c31\u662f8\u79cd\u57fa\u672c\u6570\u636e\u7c7b\u578b\u5bf9\u5e94\u7684\u5f15\u7528\u7c7b\u578b\u3002<\/p>\n\n\n\n

\u57fa\u672c\u6570\u636e\u7c7b\u578b<\/td>\u5f15\u7528\u6570\u636e\u7c7b\u578b<\/td><\/tr>
byte<\/td>Byte<\/td><\/tr>
short<\/td>Short<\/td><\/tr>
int<\/td>Integer<\/td><\/tr>
long<\/td>Long<\/td><\/tr>
char<\/td>Character<\/td><\/tr>
float<\/td>Float<\/td><\/tr>
double<\/td>Double<\/td><\/tr>
boolean<\/td>Boolean<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\u4e3a\u4ec0\u4e48\u63d0\u4f9b\u5305\u88c5\u7c7b\uff1f
Java\u4e3a\u4e86\u5b9e\u73b0\u4e00\u5207\u7686\u5bf9\u8c61\uff0c\u4e3a8\u79cd\u57fa\u672c\u7c7b\u578b\u63d0\u4f9b\u4e86\u5bf9\u5e94\u7684\u5f15\u7528\u7c7b\u578b\u3002
\u540e\u9762\u7684\u96c6\u5408\u548c\u6cdb\u578b\u5176\u5b9e\u4e5f\u53ea\u80fd\u652f\u6301\u5305\u88c5\u7c7b\u578b\uff0c\u4e0d\u652f\u6301\u57fa\u672c\u6570\u636e\u7c7b\u578b\u3002<\/p>\n\n\n\n

\u81ea\u52a8\u88c5\u7bb1\uff1a\u57fa\u672c\u7c7b\u578b\u7684\u6570\u636e\u548c\u53d8\u91cf\u53ef\u4ee5\u76f4\u63a5\u8d4b\u503c\u7ed9\u5305\u88c5\u7c7b\u578b\u7684\u53d8\u91cf\u3002
\u81ea\u52a8\u62c6\u7bb1\uff1a\u5305\u88c5\u7c7b\u578b\u7684\u53d8\u91cf\u53ef\u4ee5\u76f4\u63a5\u8d4b\u503c\u7ed9\u57fa\u672c\u6570\u636e\u7c7b\u578b\u7684\u53d8\u91cf\u3002<\/p>\n\n\n\n

\u5305\u88c5\u7c7b\u7684\u7279\u6709\u529f\u80fd
\u5305\u88c5\u7c7b\u7684\u53d8\u91cf\u7684\u9ed8\u8ba4\u503c\u53ef\u4ee5\u662fnull\uff0c\u5bb9\u9519\u7387\u66f4\u9ad8\u3002
\u53ef\u4ee5\u628a\u57fa\u672c\u7c7b\u578b\u7684\u6570\u636e\u8f6c\u6362\u6210\u5b57\u7b26\u4e32\u7c7b\u578b(\u7528\u5904\u4e0d\u5927)
\u8c03\u7528toString()\u65b9\u6cd5\u5f97\u5230\u5b57\u7b26\u4e32\u7ed3\u679c\u3002
\u8c03\u7528Integer.toString(\u57fa\u672c\u7c7b\u578b\u7684\u6570\u636e)
\u53ef\u4ee5\u628a\u5b57\u7b26\u4e32\u7c7b\u578b\u7684\u6570\u503c\u8f6c\u6362\u6210\u771f\u5b9e\u7684\u6570\u636e\u7c7b\u578b\uff08\u771f\u7684\u5f88\u6709\u7528\uff09
Integer.parseInt(\u201c\u5b57\u7b26\u4e32\u7c7b\u578b\u7684\u6574\u6570\u201d)
Double.parseDouble(\u201c\u5b57\u7b26\u4e32\u7c7b\u578b\u7684\u5c0f\u6570\u201d)<\/p>\n\n\n\n

\/**\n    \u76ee\u6807\uff1a\u660e\u767d\u5305\u88c5\u7c7b\u7684\u6982\u5ff5\uff0c\u5e76\u4f7f\u7528\u3002\n *\/\npublic class Test {\n    public static void main(String[] args) {\n        int a = 10;\n        Integer a1 = 11;\n        Integer a2 = a; \/\/ \u81ea\u52a8\u88c5\u7bb1\n        System.out.println(a);\n        System.out.println(a1);\n\n        Integer it = 100;\n        int it1 = it; \/\/ \u81ea\u52a8\u62c6\u7bb1\n        System.out.println(it1);\n\n        double db = 99.5;\n        Double db2 = db; \/\/ \u81ea\u52a8\u88c5\u7bb1\u4e86\n        double db3 = db2; \/\/ \u81ea\u52a8\u62c6\u7bb1\n        System.out.println(db3);\n\n        \/\/ int age = null; \/\/ \u62a5\u9519\u4e86\uff01\n        Integer age1 = null;\n        Integer age2 = 0;\n\n        System.out.println(\"-----------------\");\n        \/\/ 1\u3001\u5305\u88c5\u7c7b\u53ef\u4ee5\u628a\u57fa\u672c\u7c7b\u578b\u7684\u6570\u636e\u8f6c\u6362\u6210\u5b57\u7b26\u4e32\u5f62\u5f0f\u3002\uff08\u6ca1\u5565\u7528\uff09\n        Integer i3 = 23;\n        String rs = i3.toString();\n        System.out.println(rs + 1);\n\n        String rs1 = Integer.toString(i3);\n        System.out.println(rs1 + 1);\n\n        \/\/ \u53ef\u4ee5\u76f4\u63a5+\u5b57\u7b26\u4e32\u5f97\u5230\u5b57\u7b26\u4e32\u7c7b\u578b\n        String rs2 = i3 + \"\";\n        System.out.println(rs2 + 1);\n\n        System.out.println(\"-----------------\");\n\n        String number = \"23\";\n        \/\/\u8f6c\u6362\u6210\u6574\u6570\n        \/\/ int age = Integer.parseInt(number);\n        int age = Integer.valueOf(number);\n        System.out.println(age + 1);\n\n        String number1 = \"99.9\";\n        \/\/\u8f6c\u6362\u6210\u5c0f\u6570\n\/\/        double score = Double.parseDouble(number1);\n        double score = Double.valueOf(number1);\n        System.out.println(score + 0.1);\n    }\n}<\/code><\/pre>\n\n\n\n
Arrays\u7c7b<\/h2>\n\n\n\n
\u6570\u7ec4\u64cd\u4f5c\u5de5\u5177\u7c7b\uff0c\u4e13\u95e8\u7528\u4e8e\u64cd\u4f5c\u6570\u7ec4\u5143\u7d20\u7684\u3002<\/p>\n\n\n\n
Arrays\u7c7b\u7684\u5e38\u7528API<\/p>\n\n\n\n
\u65b9\u6cd5\u540d<\/td>\u8bf4\u660e<\/td><\/tr>
public static String toString\u200b(\u7c7b\u578b[] a)<\/td>\u8fd4\u56de\u6570\u7ec4\u7684\u5185\u5bb9\uff08\u5b57\u7b26\u4e32\u5f62\u5f0f\uff09<\/td><\/tr>
public static void sort\u200b(\u7c7b\u578b[] a)<\/td>\u5bf9\u6570\u7ec4\u8fdb\u884c\u9ed8\u8ba4\u5347\u5e8f\u6392\u5e8f<\/td><\/tr>
public static <T> void sort\u200b(\u7c7b\u578b[] a, Comparator<? super T> c)<\/td>\u4f7f\u7528\u6bd4\u8f83\u5668\u5bf9\u8c61\u81ea\u5b9a\u4e49\u6392\u5e8f<\/td><\/tr>
public static int binarySearch\u200b(int[] a, int key)<\/td>\u4e8c\u5206\u641c\u7d22\u6570\u7ec4\u4e2d\u7684\u6570\u636e\uff0c\u5b58\u5728\u8fd4\u56de\u7d22\u5f15\uff0c\u4e0d\u5b58\u5728\u8fd4\u56de-1<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
public class ArraysDemo1 {\n    public static void main(String[] args) {\n        \/\/ \u76ee\u6807\uff1a\u5b66\u4f1a\u4f7f\u7528Arrays\u7c7b\u7684\u5e38\u7528API ,\u5e76\u7406\u89e3\u5176\u539f\u7406\n        int[] arr = {10, 2, 55, 23, 24, 100};\n        System.out.println(arr);\n\n        \/\/ 1\u3001\u8fd4\u56de\u6570\u7ec4\u5185\u5bb9\u7684 toString(\u6570\u7ec4)\n\/\/        String rs = Arrays.toString(arr);\n\/\/        System.out.println(rs);\n\n        System.out.println(Arrays.toString(arr));\n\n        \/\/ 2\u3001\u6392\u5e8f\u7684API(\u9ed8\u8ba4\u81ea\u52a8\u5bf9\u6570\u7ec4\u5143\u7d20\u8fdb\u884c\u5347\u5e8f\u6392\u5e8f)\n        Arrays.sort(arr);\n        System.out.println(Arrays.toString(arr));\n\n        \/\/ 3\u3001\u4e8c\u5206\u641c\u7d22\u6280\u672f\uff08\u524d\u63d0\u6570\u7ec4\u5fc5\u987b\u6392\u597d\u5e8f\u624d\u652f\u6301\uff0c\u5426\u5219\u51fabug\uff09\n        int index = Arrays.binarySearch(arr, 55);\n        System.out.println(index);\n\n        \/\/ \u8fd4\u56de\u4e0d\u5b58\u5728\u5143\u7d20\u7684\u89c4\u5f8b\uff1a - \uff08\u5e94\u8be5\u63d2\u5165\u7684\u4f4d\u7f6e\u7d22\u5f15 + 1\uff09\n        int index2 = Arrays.binarySearch(arr, 22);\n        System.out.println(index2);\n\n\n        \/\/ \u6ce8\u610f\uff1a\u6570\u7ec4\u5982\u679c\u4e48\u6709\u6392\u597d\u5e8f\uff0c\u53ef\u80fd\u4f1a\u627e\u4e0d\u5230\u5b58\u5728\u7684\u5143\u7d20\uff0c\u4ece\u800c\u51fa\u73b0bug!!\n        int[] arr2 = {12, 36, 34, 25 , 13,  24,  234, 100};\n        System.out.println(Arrays.binarySearch(arr2 , 36));\n    }\n\n}<\/code><\/pre>\n\n\n\n
Arrays\u7c7b\u7684\u6392\u5e8f\u65b9\u6cd5<\/p>\n\n\n\n
\u65b9\u6cd5\u540d<\/td>\u8bf4\u660e<\/td><\/tr>
public static void sort\u200b(\u7c7b\u578b[] a)<\/td>\u5bf9\u6570\u7ec4\u8fdb\u884c\u9ed8\u8ba4\u5347\u5e8f\u6392\u5e8f<\/td><\/tr>
public static <T> void sort\u200b(\u7c7b\u578b[] a, Comparator<? super T> c)<\/td>\u4f7f\u7528\u6bd4\u8f83\u5668\u5bf9\u8c61\u81ea\u5b9a\u4e49\u6392\u5e8f<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
import java.util.Arrays;\nimport java.util.Comparator;\n\npublic class ArraysDemo2 {\n    public static void main(String[] args) {\n        \/\/ \u76ee\u6807\uff1a\u81ea\u5b9a\u4e49\u6570\u7ec4\u7684\u6392\u5e8f\u89c4\u5219\uff1aComparator\u6bd4\u8f83\u5668\u5bf9\u8c61\u3002\n        \/\/ 1\u3001Arrays\u7684sort\u65b9\u6cd5\u5bf9\u4e8e\u6709\u503c\u7279\u6027\u7684\u6570\u7ec4\u662f\u9ed8\u8ba4\u5347\u5e8f\u6392\u5e8f\n        int[] ages = {34, 12, 42, 23};\n        Arrays.sort(ages);\n        System.out.println(Arrays.toString(ages));\n\n        \/\/ 2\u3001\u9700\u6c42\uff1a\u964d\u5e8f\u6392\u5e8f\uff01(\u81ea\u5b9a\u4e49\u6bd4\u8f83\u5668\u5bf9\u8c61\uff0c\u53ea\u80fd\u652f\u6301\u5f15\u7528\u7c7b\u578b\u7684\u6392\u5e8f\uff01\uff01)\n        Integer[] ages1 = {34, 12, 42, 23};\n        \/**\n           \u53c2\u6570\u4e00\uff1a\u88ab\u6392\u5e8f\u7684\u6570\u7ec4 \u5fc5\u987b\u662f\u5f15\u7528\u7c7b\u578b\u7684\u5143\u7d20\n           \u53c2\u6570\u4e8c\uff1a\u533f\u540d\u5185\u90e8\u7c7b\u5bf9\u8c61\uff0c\u4ee3\u8868\u4e86\u4e00\u4e2a\u6bd4\u8f83\u5668\u5bf9\u8c61\u3002\n         *\/\n        Arrays.sort(ages1, new Comparator<Integer>() {\n            @Override\n            public int compare(Integer o1, Integer o2) {\n                \/\/ \u6307\u5b9a\u6bd4\u8f83\u89c4\u5219\u3002\n\/\/                if(o1 > o2){\n\/\/                    return 1;\n\/\/                }else if(o1 < o2){\n\/\/                    return -1;\n\/\/                }\n\/\/                return 0;\n                \/\/ return o1 - o2; \/\/ \u9ed8\u8ba4\u5347\u5e8f\n                return o2 - o1; \/\/  \u964d\u5e8f\n            }\n        });\n        System.out.println(Arrays.toString(ages1));\n\n        System.out.println(\"-------------------------\");\n        Student[] students = new Student[3];\n        students[0] = new Student(\"\u5434\u78ca\",23 , 175.5);\n        students[1] = new Student(\"\u8c22\u946b\",18 , 185.5);\n        students[2] = new Student(\"\u738b\u4eae\",20 , 195.5);\n        System.out.println(Arrays.toString(students));\n\n        \/\/ Arrays.sort(students);  \/\/ \u76f4\u63a5\u8fd0\u884c\u5954\u6e83\n        Arrays.sort(students, new Comparator<Student>() {\n            @Override\n            public int compare(Student o1, Student o2) {\n                \/\/ \u81ea\u5df1\u6307\u5b9a\u6bd4\u8f83\u89c4\u5219\n                \/\/ return o1.getAge() - o2.getAge(); \/\/ \u6309\u7167\u5e74\u9f84\u5347\u5e8f\u6392\u5e8f\uff01\n                \/\/ return o2.getAge() - o1.getAge(); \/\/ \u6309\u7167\u5e74\u9f84\u964d\u5e8f\u6392\u5e8f\uff01\uff01\n                \/\/ return Double.compare(o1.getHeight(), o2.getHeight()); \/\/ \u6bd4\u8f83\u6d6e\u70b9\u578b\u53ef\u4ee5\u8fd9\u6837\u5199 \u5347\u5e8f\n                return Double.compare(o2.getHeight(), o1.getHeight()); \/\/ \u6bd4\u8f83\u6d6e\u70b9\u578b\u53ef\u4ee5\u8fd9\u6837\u5199  \u964d\u5e8f\n            }\n        });\n        System.out.println(Arrays.toString(students));\n\n\n    }\n}\npublic class Student {\n    private String name;\n    private int age;\n    private double height;\n\n    public Student() {\n    }\n\n    public Student(String name, int age, double height) {\n        this.name = name;\n        this.age = age;\n        this.height = height;\n    }\n\n    public String getName() {\n        return name;\n    }\n\n    public void setName(String name) {\n        this.name = name;\n    }\n\n    public int getAge() {\n        return age;\n    }\n\n    public void setAge(int age) {\n        this.age = age;\n    }\n\n    public double getHeight() {\n        return height;\n    }\n\n    public void setHeight(double height) {\n        this.height = height;\n    }\n\n    @Override\n    public String toString() {\n        return \"Student{\" +\n                \"name='\" + name + '\\'' +\n                \", age=\" + age +\n                \", height=\" + height +\n                '}';\n    }\n}<\/code><\/pre>\n\n\n\n
Lambda<\/h2>\n\n\n\n
Lambda\u8868\u8fbe\u5f0f\u662fJDK 8\u5f00\u59cb\u540e\u7684\u4e00\u79cd\u65b0\u8bed\u6cd5\u5f62\u5f0f\u3002
\u4f5c\u7528\uff1a\u7b80\u5316\u533f\u540d\u5185\u90e8\u7c7b\u7684\u4ee3\u7801\u5199\u6cd5\u3002
(\u533f\u540d\u5185\u90e8\u7c7b\u88ab\u91cd\u5199\u65b9\u6cd5\u7684\u5f62\u53c2\u5217\u8868) -> {\u88ab\u91cd\u5199\u65b9\u6cd5\u7684\u65b9\u6cd5\u4f53\u4ee3\u7801\u3002}
\u6ce8\uff1a-> \u662f\u8bed\u6cd5\u5f62\u5f0f\uff0c\u65e0\u5b9e\u9645\u542b\u4e49
\u4ec0\u4e48\u662f\u51fd\u6570\u5f0f\u63a5\u53e3\uff1f\u9996\u5148\u5fc5\u987b\u662f\u63a5\u53e3\u3001\u5176\u6b21\u63a5\u53e3\u4e2d\u6709\u4e14\u4ec5\u6709\u4e00\u4e2a\u62bd\u8c61\u65b9\u6cd5\u7684\u5f62\u5f0f<\/p>\n\n\n\n
public class LambdaDemo1 {\n    public static void main(String[] args) {\n        \/\/ \u76ee\u6807\uff1a\u5b66\u4f1a\u4f7f\u7528Lambda\u7684\u6807\u51c6\u683c\u5f0f\u7b80\u5316\u533f\u540d\u5185\u90e8\u7c7b\u7684\u4ee3\u7801\u5f62\u5f0f\n        Animal a = new Animal() {\n            @Override\n            public void run() {\n                System.out.println(\"\u4e4c\u9f9f\u8dd1\u7684\u5f88\u6162~~~~~\");\n            }\n        };\n        a.run();\n\n        \/\/ \u6ce8\u610f\uff1alambda\u5e76\u4e0d\u662f\u53ef\u4ee5\u7b80\u5316\u6240\u6709\u533f\u540d\u533f\u540d\u5185\u90e8\u7c7b\u5f62\u5f0f\uff01\uff01\n\/\/        Animal a1 = () -> {\n\/\/            System.out.println(\"\u4e4c\u9f9f\u8dd1\u7684\u5f88\u6162~~~~~\");\n\/\/        };\n\/\/        a1.run();\n    }\n}\n\n\n\nabstract class Animal{\n    public abstract void run();\n}\npublic class LambdaDemo2 {\n    public static void main(String[] args) {\n        \/\/ \u76ee\u6807\uff1a\u5b66\u4f1a\u4f7f\u7528Lambda\u7684\u6807\u51c6\u683c\u5f0f\u7b80\u5316\u533f\u540d\u5185\u90e8\u7c7b\u7684\u4ee3\u7801\u5f62\u5f0f\n        \/\/ \u6ce8\u610f\uff1aLambda\u53ea\u80fd\u7b80\u5316\u63a5\u53e3\u4e2d\u53ea\u6709\u4e00\u4e2a\u62bd\u8c61\u65b9\u6cd5\u7684\u533f\u540d\u5185\u90e8\u7c7b\u5f62\u5f0f\uff08\u51fd\u6570\u5f0f\u63a5\u53e3\uff09\n\/\/        Swimming s1 = new Swimming() {\n\/\/            @Override\n\/\/            public void swim() {\n\/\/                System.out.println(\"\u8001\u5e08\u6e38\u6cf3\u8d3c\u6e9c~~~~~\");\n\/\/            }\n\/\/        };\n\n\/\/        Swimming s1 = () -> {\n\/\/            System.out.println(\"\u8001\u5e08\u6e38\u6cf3\u8d3c\u6e9c~~~~~\");\n\/\/        };\n\n        Swimming s1 = () -> System.out.println(\"\u8001\u5e08\u6e38\u6cf3\u8d3c\u6e9c~~~~~\");\n        go(s1);\n\n        System.out.println(\"---------------------\");\n\/\/        go(new Swimming() {\n\/\/            @Override\n\/\/            public void swim() {\n\/\/                System.out.println(\"\u5b66\u751f\u6e38\u6cf3\u5f88\u5f00\u5fc3~~~\");\n\/\/            }\n\/\/        });\n\n\/\/        go(() ->{\n\/\/                System.out.println(\"\u5b66\u751f\u6e38\u6cf3\u5f88\u5f00\u5fc3~~~\");\n\/\/        });\n\n        go(() -> System.out.println(\"\u5b66\u751f\u6e38\u6cf3\u5f88\u5f00\u5fc3~~~\"));\n\n\n    }\n\n    public static void go(Swimming s){\n        System.out.println(\"\u5f00\u59cb\u3002\u3002\u3002\");\n        s.swim();\n        System.out.println(\"\u7ed3\u675f\u3002\u3002\u3002\");\n    }\n}\n\n@FunctionalInterface \/\/ \u4e00\u65e6\u52a0\u4e0a\u8fd9\u4e2a\u6ce8\u89e3\u5fc5\u987b\u662f\u51fd\u6570\u5f0f\u63a5\u53e3\uff0c\u91cc\u9762\u53ea\u80fd\u6709\u4e00\u4e2a\u62bd\u8c61\u65b9\u6cd5\ninterface Swimming{\n    void swim();\n}\npublic class LambdaDemo3 {\n    public static void main(String[] args) {\n        Integer[] ages1 = {34, 12, 42, 23};\n        \/**\n         \u53c2\u6570\u4e00\uff1a\u88ab\u6392\u5e8f\u7684\u6570\u7ec4 \u5fc5\u987b\u662f\u5f15\u7528\u7c7b\u578b\u7684\u5143\u7d20\n         \u53c2\u6570\u4e8c\uff1a\u533f\u540d\u5185\u90e8\u7c7b\u5bf9\u8c61\uff0c\u4ee3\u8868\u4e86\u4e00\u4e2a\u6bd4\u8f83\u5668\u5bf9\u8c61\u3002\n         *\/\n\/\/        Arrays.sort(ages1, new Comparator<Integer>() {\n\/\/            @Override\n\/\/            public int compare(Integer o1, Integer o2) {\n\/\/                return o2 - o1; \/\/  \u964d\u5e8f\n\/\/            }\n\/\/        });\n\n\/\/        Arrays.sort(ages1, (Integer o1, Integer o2) -> {\n\/\/                return o2 - o1; \/\/  \u964d\u5e8f\n\/\/        });\n\n\n\/\/        Arrays.sort(ages1, ( o1,  o2) -> {\n\/\/            return o2 - o1; \/\/  \u964d\u5e8f\n\/\/        });\n\n        Arrays.sort(ages1, ( o1,  o2 ) ->  o2 - o1 );\n\n        System.out.println(Arrays.toString(ages1));\n\n        System.out.println(\"---------------------------\");\n        JFrame win = new JFrame(\"\u767b\u5f55\u754c\u9762\");\n        JButton btn = new JButton(\"\u6211\u662f\u4e00\u4e2a\u5f88\u5927\u7684\u6309\u94ae\");\n\/\/        btn.addActionListener(new ActionListener() {\n\/\/            @Override\n\/\/            public void actionPerformed(ActionEvent e) {\n\/\/                System.out.println(\"\u6709\u4eba\u70b9\u6211\uff0c\u70b9\u6211\uff0c\u70b9\u6211\uff01\uff01\");\n\/\/            }\n\/\/        });\n\n\/\/        btn.addActionListener((ActionEvent e) -> {\n\/\/                System.out.println(\"\u6709\u4eba\u70b9\u6211\uff0c\u70b9\u6211\uff0c\u70b9\u6211\uff01\uff01\");\n\/\/        });\n\n\/\/        btn.addActionListener(( e) -> {\n\/\/            System.out.println(\"\u6709\u4eba\u70b9\u6211\uff0c\u70b9\u6211\uff0c\u70b9\u6211\uff01\uff01\");\n\/\/        });\n\n\/\/        btn.addActionListener( e -> {\n\/\/            System.out.println(\"\u6709\u4eba\u70b9\u6211\uff0c\u70b9\u6211\uff0c\u70b9\u6211\uff01\uff01\");\n\/\/        });\n\n        btn.addActionListener( e -> System.out.println(\"\u6709\u4eba\u70b9\u6211\uff0c\u70b9\u6211\uff0c\u70b9\u6211\uff01\uff01\") );\n\n\n\n        win.add(btn);\n        win.setSize(400, 300);\n        win.setVisible(true);\n    }\n}<\/code><\/pre>\n\n\n\n
Lambda\u8868\u8fbe\u5f0f\u7684\u7701\u7565\u5199\u6cd5\uff08\u8fdb\u4e00\u6b65\u5728Lambda\u8868\u8fbe\u5f0f\u7684\u57fa\u7840\u4e0a\u7ee7\u7eed\u7b80\u5316\uff09
\u00b7\u53c2\u6570\u7c7b\u578b\u53ef\u4ee5\u7701\u7565\u4e0d\u5199\u3002
\u00b7\u5982\u679c\u53ea\u6709\u4e00\u4e2a\u53c2\u6570\uff0c\u53c2\u6570\u7c7b\u578b\u53ef\u4ee5\u7701\u7565\uff0c\u540c\u65f6()\u4e5f\u53ef\u4ee5\u7701\u7565\u3002
\u00b7\u5982\u679cLambda\u8868\u8fbe\u5f0f\u7684\u65b9\u6cd5\u4f53\u4ee3\u7801\u53ea\u6709\u4e00\u884c\u4ee3\u7801\u3002\u53ef\u4ee5\u7701\u7565\u5927\u62ec\u53f7\u4e0d\u5199,\u540c\u65f6\u8981\u7701\u7565\u5206\u53f7\uff01
\u00b7\u5982\u679cLambda\u8868\u8fbe\u5f0f\u7684\u65b9\u6cd5\u4f53\u4ee3\u7801\u53ea\u6709\u4e00\u884c\u4ee3\u7801\u3002\u53ef\u4ee5\u7701\u7565\u5927\u62ec\u53f7\u4e0d\u5199\u3002\u6b64\u65f6\uff0c\u5982\u679c\u8fd9\u884c\u4ee3\u7801\u662freturn\u8bed\u53e5\uff0c\u5fc5\u987b\u7701\u7565return\u4e0d\u5199\uff0c\u540c\u65f6\u4e5f\u5fc5\u987b\u7701\u7565\";\"\u4e0d\u5199<\/p>\n\n\n\n
\u96c6\u5408Collection<\/h2>\n\n\n\n
Collection\u5355\u5217\u96c6\u5408\uff0c\u6bcf\u4e2a\u5143\u7d20\uff08\u6570\u636e\uff09\u53ea\u5305\u542b\u4e00\u4e2a\u503c\u3002
Map\u53cc\u5217\u96c6\u5408\uff0c\u6bcf\u4e2a\u5143\u7d20\u5305\u542b\u4e24\u4e2a\u503c\uff08\u952e\u503c\u5bf9\uff09\u3002<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\"\"<\/figure>\n\n\n\n
Collection\u96c6\u5408\u7279\u70b9
List\u7cfb\u5217\u96c6\u5408\uff1a\u6dfb\u52a0\u7684\u5143\u7d20\u662f\u6709\u5e8f\u3001\u53ef\u91cd\u590d\u3001\u6709\u7d22\u5f15\u3002
ArrayList\u3001LinekdList \uff1a\u6709\u5e8f\u3001\u53ef\u91cd\u590d\u3001\u6709\u7d22\u5f15\u3002
Set\u7cfb\u5217\u96c6\u5408\uff1a\u6dfb\u52a0\u7684\u5143\u7d20\u662f\u65e0\u5e8f\u3001\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\u3002
HashSet: \u65e0\u5e8f\u3001\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\uff1bLinkedHashSet: \u6709\u5e8f\u3001\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\u3002
TreeSet\uff1a\u6309\u7167\u5927\u5c0f\u9ed8\u8ba4\u5347\u5e8f\u6392\u5e8f\u3001\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\u3002<\/p>\n\n\n\n
\u6cdb\u578b
\u96c6\u5408\u90fd\u662f\u6cdb\u578b\u7684\u5f62\u5f0f\uff0c\u53ef\u4ee5\u5728\u7f16\u8bd1\u9636\u6bb5\u7ea6\u675f\u96c6\u5408\u53ea\u80fd\u64cd\u4f5c\u67d0\u79cd\u6570\u636e\u7c7b\u578b
Collection<String> lists = new ArrayList<String>();
Collection<String> lists = new ArrayList<>(); \/\/ JDK 1.7\u5f00\u59cb\u540e\u9762\u7684\u6cdb\u578b\u7c7b\u578b\u7533\u660e\u53ef\u4ee5\u7701\u7565\u4e0d\u5199
\u6ce8\u610f\uff1a\u96c6\u5408\u548c\u6cdb\u578b\u90fd\u53ea\u80fd\u652f\u6301\u5f15\u7528\u6570\u636e\u7c7b\u578b\uff0c\u4e0d\u652f\u6301\u57fa\u672c\u6570\u636e\u7c7b\u578b\uff0c\u6240\u4ee5\u96c6\u5408\u4e2d\u5b58\u50a8\u7684\u5143\u7d20\u90fd\u8ba4\u4e3a\u662f\u5bf9\u8c61\u3002
error\uff1aCollection<int> lists = new ArrayList<>();
\u5982\u679c\u96c6\u5408\u4e2d\u8981\u5b58\u50a8\u57fa\u672c\u7c7b\u578b\u7684\u6570\u636e\u600e\u4e48\u529e\uff1f
\/\/ \u5b58\u50a8\u57fa\u672c\u7c7b\u578b\u4f7f\u7528\u5305\u88c5\u7c7b
Collection<integer> lists = new ArrayList<>();
Collection<Double> lists = new ArrayList<>();<\/p>\n\n\n\n
Collection\u96c6\u5408
Collection\u662f\u5355\u5217\u96c6\u5408\u7684\u7956\u5b97\u63a5\u53e3\uff0c\u5b83\u7684\u529f\u80fd\u662f\u5168\u90e8\u5355\u5217\u96c6\u5408\u90fd\u53ef\u4ee5\u7ee7\u627f\u4f7f\u7528\u7684\u3002<\/p>\n\n\n\n
Collection API:<\/p>\n\n\n\n
\u65b9\u6cd5\u540d\u79f0<\/td>\u8bf4\u660e<\/td><\/tr>
public boolean add(E e)<\/td>\u628a\u7ed9\u5b9a\u7684\u5bf9\u8c61\u6dfb\u52a0\u5230\u5f53\u524d\u96c6\u5408\u4e2d <\/td><\/tr>
public void clear() <\/td>\u6e05\u7a7a\u96c6\u5408\u4e2d\u6240\u6709\u7684\u5143\u7d20<\/td><\/tr>
public boolean remove(E e)<\/td>\u628a\u7ed9\u5b9a\u7684\u5bf9\u8c61\u5728\u5f53\u524d\u96c6\u5408\u4e2d\u5220\u9664<\/td><\/tr>
public boolean contains(Object obj)<\/td>\u5224\u65ad\u5f53\u524d\u96c6\u5408\u4e2d\u662f\u5426\u5305\u542b\u7ed9\u5b9a\u7684\u5bf9\u8c61<\/td><\/tr>
public boolean isEmpty()<\/td>\u5224\u65ad\u5f53\u524d\u96c6\u5408\u662f\u5426\u4e3a\u7a7a<\/td><\/tr>
public int size()<\/td>\u8fd4\u56de\u96c6\u5408\u4e2d\u5143\u7d20\u7684\u4e2a\u6570\u3002<\/td><\/tr>
public Object[] toArray()<\/td>\u628a\u96c6\u5408\u4e2d\u7684\u5143\u7d20\uff0c\u5b58\u50a8\u5230\u6570\u7ec4\u4e2d<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\n\/**\n    \u76ee\u6807\uff1a\u660e\u786eCollection\u96c6\u5408\u4f53\u7cfb\u7684\u7279\u70b9\n *\/\npublic class CollectionDemo1 {\n    public static void main(String[] args) {\n        \/\/ \u6709\u5e8f \u53ef\u91cd\u590d \u6709\u7d22\u5f15\n        Collection list = new ArrayList();\n        list.add(\"Java\");\n        list.add(\"Java\");\n        list.add(\"Mybatis\");\n        list.add(23);\n        list.add(23);\n        list.add(false);\n        list.add(false);\n        System.out.println(list);\n\n        \/\/ \u65e0\u5e8f \u4e0d\u91cd\u590d  \u65e0\u7d22\u5f15\n        Collection list1 = new HashSet();\n        list1.add(\"Java\");\n        list1.add(\"Java\");\n        list1.add(\"Mybatis\");\n        list1.add(23);\n        list1.add(23);\n        list1.add(false);\n        list1.add(false);\n        System.out.println(list1);\n\n        System.out.println(\"-----------------------------\");\n        \/\/ Collection<String> list2 = new ArrayList<String>();\n        Collection<String> list2 = new ArrayList<>(); \/\/ JDK 7\u5f00\u59cb\u4e4b\u540e\u540e\u9762\u7c7b\u578b\u7533\u660e\u53ef\u4ee5\u4e0d\u5199\n        list2.add(\"Java\");\n        \/\/ list2.add(23);\n        list2.add(\"\u9ed1\u9a6c\");\n\n        \/\/ \u96c6\u5408\u548c\u6cdb\u578b\u4e0d\u652f\u6301\u57fa\u672c\u6570\u636e\u7c7b\u578b\uff0c\u53ea\u80fd\u652f\u6301\u5f15\u7528\u6570\u636e\u7c7b\u578b\n        \/\/ Collection<int> list3 = new ArrayList<>();\n        Collection<Integer> list3 = new ArrayList<>();\n        list3.add(23);\n        list3.add(233);\n        list3.add(2333);\n\n        Collection<Double> list4 = new ArrayList<>();\n        list4.add(23.4);\n        list4.add(233.0);\n        list4.add(233.3);\n    }\n}<\/code><\/pre>\n\n\n\n
\u8fed\u4ee3\u5668\u904d\u5386\u6982\u8ff0
\u904d\u5386\u5c31\u662f\u4e00\u4e2a\u4e00\u4e2a\u7684\u628a\u5bb9\u5668\u4e2d\u7684\u5143\u7d20\u8bbf\u95ee\u4e00\u904d\u3002
\u8fed\u4ee3\u5668\u5728Java\u4e2d\u7684\u4ee3\u8868\u662fIterator\uff0c\u8fed\u4ee3\u5668\u662f\u96c6\u5408\u7684\u4e13\u7528\u7684\u904d\u5386\u65b9\u5f0f\u3002<\/p>\n\n\n\n
Collection\u96c6\u5408\u83b7\u53d6\u8fed\u4ee3\u5668
Iterator iterator() \u8fd4\u56de\u96c6\u5408\u4e2d\u7684\u8fed\u4ee3\u5668\u5bf9\u8c61\uff0c\u8be5\u8fed\u4ee3\u5668\u5bf9\u8c61\u9ed8\u8ba4\u6307\u5411\u5f53\u524d\u96c6\u5408\u76840\u7d22\u5f15
Iterator\u4e2d\u7684\u5e38\u7528\u65b9\u6cd5
boolean hasNext() \u8be2\u95ee\u5f53\u524d\u4f4d\u7f6e\u662f\u5426\u6709\u5143\u7d20\u5b58\u5728\uff0c\u5b58\u5728\u8fd4\u56detrue ,\u4e0d\u5b58\u5728\u8fd4\u56defalse
E next() \u83b7\u53d6\u5f53\u524d\u4f4d\u7f6e\u7684\u5143\u7d20\uff0c\u5e76\u540c\u65f6\u5c06\u8fed\u4ee3\u5668\u5bf9\u8c61\u79fb\u5411\u4e0b\u4e00\u4e2a\u4f4d\u7f6e\uff0c\u6ce8\u610f\u9632\u6b62\u53d6\u51fa\u8d8a\u754c<\/p>\n\n\n\n
\/**\n    \u76ee\u6807\uff1aCollection\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u3002\n\n    \u4ec0\u4e48\u662f\u904d\u5386? \u4e3a\u4ec0\u4e48\u5f00\u53d1\u4e2d\u8981\u904d\u5386\uff1f\n        \u904d\u5386\u5c31\u662f\u4e00\u4e2a\u4e00\u4e2a\u7684\u628a\u5bb9\u5668\u4e2d\u7684\u5143\u7d20\u8bbf\u95ee\u4e00\u904d\u3002\n        \u5f00\u53d1\u4e2d\u7ecf\u5e38\u8981\u7edf\u8ba1\u5143\u7d20\u7684\u603b\u548c\uff0c\u627e\u6700\u503c\uff0c\u627e\u51fa\u67d0\u4e2a\u6570\u636e\u7136\u540e\u5e72\u6389\u7b49\u7b49\u4e1a\u52a1\u90fd\u9700\u8981\u904d\u5386\u3002\n\n    Collection\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u662f\u5168\u90e8\u96c6\u5408\u90fd\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528\u7684\uff0c\u6240\u4ee5\u6211\u4eec\u5b66\u4e60\u5b83\u3002\n    Collection\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u6709\u4e09\u79cd:\n        \uff081\uff09\u8fed\u4ee3\u5668\u3002\n        \uff082\uff09foreach(\u589e\u5f3afor\u5faa\u73af)\u3002\n        \uff083\uff09JDK 1.8\u5f00\u59cb\u4e4b\u540e\u7684\u65b0\u6280\u672fLambda\u8868\u8fbe\u5f0f(\u4e86\u89e3)\n\n    a.\u8fed\u4ee3\u5668\u904d\u5386\u96c6\u5408\u3002\n        -- \u65b9\u6cd5\uff1a\n             public Iterator iterator(): \u83b7\u53d6\u96c6\u5408\u5bf9\u5e94\u7684\u8fed\u4ee3\u5668\uff0c\u7528\u6765\u904d\u5386\u96c6\u5408\u4e2d\u7684\u5143\u7d20\u7684\n             boolean hasNext():\u5224\u65ad\u662f\u5426\u6709\u4e0b\u4e00\u4e2a\u5143\u7d20\uff0c\u6709\u8fd4\u56detrue ,\u53cd\u4e4b\u3002\n             E next():\u83b7\u53d6\u4e0b\u4e00\u4e2a\u5143\u7d20\u503c\uff01\n        --\u6d41\u7a0b\uff1a\n            1.\u5148\u83b7\u53d6\u5f53\u524d\u96c6\u5408\u7684\u8fed\u4ee3\u5668\n                Iterator<String> it = lists.iterator();\n            2.\u5b9a\u4e49\u4e00\u4e2awhile\u5faa\u73af\uff0c\u95ee\u4e00\u6b21\u53d6\u4e00\u6b21\u3002\n              \u901a\u8fc7it.hasNext()\u8be2\u95ee\u662f\u5426\u6709\u4e0b\u4e00\u4e2a\u5143\u7d20\uff0c\u6709\u5c31\u901a\u8fc7\n              it.next()\u53d6\u51fa\u4e0b\u4e00\u4e2a\u5143\u7d20\u3002\n    \u5c0f\u7ed3\uff1a\n        \u8bb0\u4f4f\u4ee3\u7801\u3002\n *\/\npublic class CollectionDemo01 {\n    public static void main(String[] args) {\n        ArrayList<String> lists = new ArrayList<>();\n        lists.add(\"\u8d75\u654f\");\n        lists.add(\"\u5c0f\u662d\");\n        lists.add(\"\u7d20\u7d20\");\n        lists.add(\"\u706d\u7edd\");\n        System.out.println(lists);\n        \/\/ [\u8d75\u654f, \u5c0f\u662d, \u7d20\u7d20, \u706d\u7edd]\n        \/\/   it\n\n        \/\/ 1\u3001\u5f97\u5230\u5f53\u524d\u96c6\u5408\u7684\u8fed\u4ee3\u5668\u5bf9\u8c61\u3002\n        Iterator<String> it = lists.iterator();\n\/\/        String ele = it.next();\n\/\/        System.out.println(ele);\n\/\/        System.out.println(it.next());\n\/\/        System.out.println(it.next());\n\/\/        System.out.println(it.next());\n        \/\/ System.out.println(it.next()); \/\/ NoSuchElementException \u51fa\u73b0\u65e0\u6b64\u5143\u7d20\u5f02\u5e38\u7684\u9519\u8bef\n\n        \/\/ 2\u3001\u5b9a\u4e49while\u5faa\u73af\n        while (it.hasNext()){\n            String ele = it.next();\n            System.out.println(ele);\n        }\n        System.out.println(\"-----------------------------\");\n\n    }\n}<\/code><\/pre>\n\n\n\n
foreach\/\u589e\u5f3afor\u5faa\u73af<\/p>\n\n\n\n
\/**\n     \u76ee\u6807\uff1aCollection\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u3002\n\n     \u4ec0\u4e48\u662f\u904d\u5386? \u4e3a\u4ec0\u4e48\u5f00\u53d1\u4e2d\u8981\u904d\u5386\uff1f\n     \u904d\u5386\u5c31\u662f\u4e00\u4e2a\u4e00\u4e2a\u7684\u628a\u5bb9\u5668\u4e2d\u7684\u5143\u7d20\u8bbf\u95ee\u4e00\u904d\u3002\n     \u5f00\u53d1\u4e2d\u7ecf\u5e38\u8981\u7edf\u8ba1\u5143\u7d20\u7684\u603b\u548c\uff0c\u627e\u6700\u503c\uff0c\u627e\u51fa\u67d0\u4e2a\u6570\u636e\u7136\u540e\u5e72\u6389\u7b49\u7b49\u4e1a\u52a1\u90fd\u9700\u8981\u904d\u5386\u3002\n\n     Collection\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u662f\u5168\u90e8\u96c6\u5408\u90fd\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528\u7684\uff0c\u6240\u4ee5\u6211\u4eec\u5b66\u4e60\u5b83\u3002\n     Collection\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u6709\u4e09\u79cd:\n         \uff081\uff09\u8fed\u4ee3\u5668\u3002\n         \uff082\uff09foreach(\u589e\u5f3afor\u5faa\u73af)\u3002\n         \uff083\uff09JDK 1.8\u5f00\u59cb\u4e4b\u540e\u7684\u65b0\u6280\u672fLambda\u8868\u8fbe\u5f0f\u3002\n\n     b.foreach(\u589e\u5f3afor\u5faa\u73af)\u904d\u5386\u96c6\u5408\u3002\n         foreach\u662f\u4e00\u79cd\u904d\u5386\u5f62\u5f0f\uff0c\u53ef\u4ee5\u904d\u5386\u96c6\u5408\u6216\u8005\u6570\u7ec4\u3002\n         foreach\u904d\u5386\u96c6\u5408\u5b9e\u9645\u4e0a\u662f\u8fed\u4ee3\u5668\u904d\u5386\u96c6\u5408\u7684\u7b80\u5316\u5199\u6cd5\u3002\n         foreach\u904d\u5386\u7684\u5173\u952e\u662f\u8bb0\u4f4f\u683c\u5f0f\uff1a\n            for(\u88ab\u904d\u5386\u96c6\u5408\u6216\u8005\u6570\u7ec4\u4e2d\u5143\u7d20\u7684\u7c7b\u578b \u53d8\u91cf\u540d\u79f0 : \u88ab\u904d\u5386\u96c6\u5408\u6216\u8005\u6570\u7ec4){\n\n            }\n *\/\npublic class CollectionDemo02 {\n    public static void main(String[] args) {\n        Collection<String> lists = new ArrayList<>();\n        lists.add(\"\u8d75\u654f\");\n        lists.add(\"\u5c0f\u662d\");\n        lists.add(\"\u6bb7\u7d20\u7d20\");\n        lists.add(\"\u5468\u82b7\u82e5\");\n        System.out.println(lists);\n        \/\/ [\u8d75\u654f, \u5c0f\u662d, \u6bb7\u7d20\u7d20, \u5468\u82b7\u82e5]\n        \/\/  ele\n\n        for (String ele : lists) {\n            System.out.println(ele);\n        }\n\n        System.out.println(\"------------------\");\n        double[] scores = {100, 99.5 , 59.5};\n        for (double score : scores) {\n            System.out.println(score);\n\/\/            if(score == 59.5){\n\/\/                score = 100.0; \/\/ \u4fee\u6539\u65e0\u610f\u4e49\uff0c\u4e0d\u4f1a\u5f71\u54cd\u6570\u7ec4\u7684\u5143\u7d20\u503c\u3002\n\/\/            }\n        }\n        System.out.println(Arrays.toString(scores));\n\n    }\n}<\/code><\/pre>\n\n\n\n
Lambda\u8868\u8fbe\u5f0f\u904d\u5386\u96c6\u5408
\u5f97\u76ca\u4e8eJDK 8\u5f00\u59cb\u7684\u65b0\u6280\u672fLambda\u8868\u8fbe\u5f0f\uff0c\u63d0\u4f9b\u4e86\u4e00\u79cd\u66f4\u7b80\u5355\u3001\u66f4\u76f4\u63a5\u7684\u904d\u5386\u96c6\u5408\u7684\u65b9\u5f0f\u3002
Collection\u7ed3\u5408Lambda\u904d\u5386\u7684API
default void forEach(Consumer action): \u7ed3\u5408lambda\u904d\u5386\u96c6\u5408<\/p>\n\n\n\n
\/**\n     \u76ee\u6807\uff1aCollection\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u3002\n\n     \u4ec0\u4e48\u662f\u904d\u5386? \u4e3a\u4ec0\u4e48\u5f00\u53d1\u4e2d\u8981\u904d\u5386\uff1f\n     \u904d\u5386\u5c31\u662f\u4e00\u4e2a\u4e00\u4e2a\u7684\u628a\u5bb9\u5668\u4e2d\u7684\u5143\u7d20\u8bbf\u95ee\u4e00\u904d\u3002\n     \u5f00\u53d1\u4e2d\u7ecf\u5e38\u8981\u7edf\u8ba1\u5143\u7d20\u7684\u603b\u548c\uff0c\u627e\u6700\u503c\uff0c\u627e\u51fa\u67d0\u4e2a\u6570\u636e\u7136\u540e\u5e72\u6389\u7b49\u7b49\u4e1a\u52a1\u90fd\u9700\u8981\u904d\u5386\u3002\n\n     Collection\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u662f\u5168\u90e8\u96c6\u5408\u90fd\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528\u7684\uff0c\u6240\u4ee5\u6211\u4eec\u5b66\u4e60\u5b83\u3002\n     Collection\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u6709\u4e09\u79cd:\n         \uff081\uff09\u8fed\u4ee3\u5668\u3002\n         \uff082\uff09foreach(\u589e\u5f3afor\u5faa\u73af)\u3002\n         \uff083\uff09JDK 1.8\u5f00\u59cb\u4e4b\u540e\u7684\u65b0\u6280\u672fLambda\u8868\u8fbe\u5f0f\u3002\n     c.JDK 1.8\u5f00\u59cb\u4e4b\u540e\u7684\u65b0\u6280\u672fLambda\u8868\u8fbe\u5f0f\u3002\n *\/\npublic class CollectionDemo03 {\n    public static void main(String[] args) {\n        Collection<String> lists = new ArrayList<>();\n        lists.add(\"\u8d75\u654f\");\n        lists.add(\"\u5c0f\u662d\");\n        lists.add(\"\u6bb7\u7d20\u7d20\");\n        lists.add(\"\u5468\u82b7\u82e5\");\n        System.out.println(lists);\n        \/\/ [\u8d75\u654f, \u5c0f\u662d, \u6bb7\u7d20\u7d20, \u5468\u82b7\u82e5]\n        \/\/  s\n        lists.forEach(new Consumer<String>() {\n            @Override\n            public void accept(String s) {\n                System.out.println(s);\n            }\n        });\n\n\/\/        lists.forEach(s -> {\n\/\/                System.out.println(s);\n\/\/        });\n\n        \/\/ lists.forEach(s ->  System.out.println(s) );\n\n        lists.forEach(System.out::println );\n\n    }\n}<\/code><\/pre>\n\n\n\n
List\u96c6\u5408<\/h2>\n\n\n\n
List\u7cfb\u5217\u96c6\u5408\u7279\u70b9
ArrayList\u3001LinekdList \uff1a\u6709\u5e8f\uff0c\u53ef\u91cd\u590d\uff0c\u6709\u7d22\u5f15\u3002
\u6709\u5e8f\uff1a\u5b58\u50a8\u548c\u53d6\u51fa\u7684\u5143\u7d20\u987a\u5e8f\u4e00\u81f4
\u6709\u7d22\u5f15\uff1a\u53ef\u4ee5\u901a\u8fc7\u7d22\u5f15\u64cd\u4f5c\u5143\u7d20
\u53ef\u91cd\u590d\uff1a\u5b58\u50a8\u7684\u5143\u7d20\u53ef\u4ee5\u91cd\u590d<\/p>\n\n\n\n
List\u96c6\u5408\u7279\u6709\u65b9\u6cd5
List\u96c6\u5408\u56e0\u4e3a\u652f\u6301\u7d22\u5f15\uff0c\u6240\u4ee5\u591a\u4e86\u5f88\u591a\u7d22\u5f15\u64cd\u4f5c\u7684\u72ec\u7279api\uff0c\u5176\u4ed6Collection\u7684\u529f\u80fdList\u4e5f\u90fd\u7ee7\u627f\u4e86\u3002<\/p>\n\n\n\n
\u65b9\u6cd5\u540d\u79f0<\/td>\u8bf4\u660e<\/td><\/tr>
void add(int index,E element)<\/td>\u5728\u6b64\u96c6\u5408\u4e2d\u7684\u6307\u5b9a\u4f4d\u7f6e\u63d2\u5165\u6307\u5b9a\u7684\u5143\u7d20<\/td><\/tr>
E remove(int index)<\/td>\u5220\u9664\u6307\u5b9a\u7d22\u5f15\u5904\u7684\u5143\u7d20\uff0c\u8fd4\u56de\u88ab\u5220\u9664\u7684\u5143\u7d20<\/td><\/tr>
E set(int index,E element)<\/td>\u4fee\u6539\u6307\u5b9a\u7d22\u5f15\u5904\u7684\u5143\u7d20\uff0c\u8fd4\u56de\u88ab\u4fee\u6539\u7684\u5143\u7d20<\/td><\/tr>
E get(int index)<\/td>\u8fd4\u56de\u6307\u5b9a\u7d22\u5f15\u5904\u7684\u5143\u7d20<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\/**\n      \u76ee\u6807\uff1aArrayList\u96c6\u5408\u3002\n\n      Collection\u96c6\u5408\u4f53\u7cfb\u7684\u7279\u70b9:\n         Set\u7cfb\u5217\u96c6\u5408\uff1a \u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u65e0\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u7684\u3002\n             -- HashSet\uff1a\u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u65e0\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u7684\u3002\n             -- LinkedHashSet\uff1a\u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u6709\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u7684\u3002\n         List\u7cfb\u5217\u96c6\u5408\uff1a\u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u6709\u5e8f\uff0c\u53ef\u91cd\u590d\uff0c\u6709\u7d22\u5f15\u7684\u3002\n             -- LinkedList\uff1a \u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u6709\u5e8f\uff0c\u53ef\u91cd\u590d\uff0c\u6709\u7d22\u5f15\u7684\u3002\n             -- ArrayList\uff1a \u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u6709\u5e8f\uff0c\u53ef\u91cd\u590d\uff0c\u6709\u7d22\u5f15\u7684\u3002\n             -- Vector \u662f\u7ebf\u7a0b\u5b89\u5168\u7684\uff0c\u901f\u5ea6\u6162\uff0c\u5de5\u4f5c\u4e2d\u5f88\u5c11\u4f7f\u7528\u3002\n\n         1\u3001List\u96c6\u5408\u7ee7\u627f\u4e86Collection\u96c6\u5408\u7684\u5168\u90e8\u529f\u80fd\uff0c\"\u540c\u65f6\u56e0\u4e3aList\u7cfb\u5217\u96c6\u5408\u6709\u7d22\u5f15\"\uff0c\n         2\u3001\u56e0\u4e3aList\u96c6\u5408\u591a\u4e86\u7d22\u5f15\uff0c\u6240\u4ee5\u591a\u4e86\u5f88\u591a\u6309\u7167\u7d22\u5f15\u64cd\u4f5c\u5143\u7d20\u7684\u529f\u80fd:\n         3\u3001ArrayList\u5b9e\u73b0\u7c7b\u96c6\u5408\u5e95\u5c42\u57fa\u4e8e\u6570\u7ec4\u5b58\u50a8\u6570\u636e\u7684\uff0c\u67e5\u8be2\u5feb\uff0c\u589e\u5220\u6162\uff01\n             - public void add(int index, E element): \u5c06\u6307\u5b9a\u7684\u5143\u7d20\uff0c\u6dfb\u52a0\u5230\u8be5\u96c6\u5408\u4e2d\u7684\u6307\u5b9a\u4f4d\u7f6e\u4e0a\u3002\n             - public E get(int index):\u8fd4\u56de\u96c6\u5408\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20\u3002\n             - public E remove(int index): \u79fb\u9664\u5217\u8868\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20, \u8fd4\u56de\u7684\u662f\u88ab\u79fb\u9664\u7684\u5143\u7d20\u3002\n             - public E set(int index, E element):\u7528\u6307\u5b9a\u5143\u7d20\u66ff\u6362\u96c6\u5408\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20,\u8fd4\u56de\u66f4\u65b0\u524d\u7684\u5143\u7d20\u503c\u3002\n      \u5c0f\u7ed3\uff1a\n            ArrayList\u96c6\u5408\u7684\u5e95\u5c42\u662f\u57fa\u4e8e\u6570\u7ec4\u5b58\u50a8\u6570\u636e\u3002\u67e5\u8be2\u5feb\uff0c\u589e\u5220\u6162\uff01\uff08\u76f8\u5bf9\u7684\uff09\n *\/\npublic class ListDemo01 {\n    public static void main(String[] args) {\n        \/\/ 1.\u521b\u5efa\u4e00\u4e2aArrayList\u96c6\u5408\u5bf9\u8c61\uff1a\n        \/\/ List:\u6709\u5e8f\uff0c\u53ef\u91cd\u590d\uff0c\u6709\u7d22\u5f15\u7684\u3002\n        ArrayList<String> list = new ArrayList<>(); \/\/ \u4e00\u884c\u7ecf\u5178\u4ee3\u7801\uff01\n        list.add(\"Java\");\n        list.add(\"Java\");\n        list.add(\"HTML\");\n        list.add(\"HTML\");\n        list.add(\"MySQL\");\n        list.add(\"MySQL\");\n\n        \/\/ 2.\u5728\u67d0\u4e2a\u7d22\u5f15\u4f4d\u7f6e\u63d2\u5165\u5143\u7d20\u3002\n        list.add(2, \"\u9ed1\u9a6c\");\n        System.out.println(list);\n\n        \/\/ 3.\u6839\u636e\u7d22\u5f15\u5220\u9664\u5143\u7d20,\u8fd4\u56de\u88ab\u5220\u9664\u5143\u7d20\n        System.out.println(list.remove(1));\n        System.out.println(list);\n\n        \/\/ 4.\u6839\u636e\u7d22\u5f15\u83b7\u53d6\u5143\u7d20:public E get(int index):\u8fd4\u56de\u96c6\u5408\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20\u3002\n        System.out.println(list.get(1));\n\n        \/\/ 5.\u4fee\u6539\u7d22\u5f15\u4f4d\u7f6e\u5904\u7684\u5143\u7d20: public E set(int index, E element)\n        System.out.println(list.set(1, \"\u4f20\u667a\u6559\u80b2\"));\n        System.out.println(list);\n    }\n}<\/code><\/pre>\n\n\n\n
ArrayList\u5e95\u5c42\u662f\u57fa\u4e8e\u6570\u7ec4\u5b9e\u73b0\u7684\uff0c\u6839\u636e\u67e5\u8be2\u5143\u7d20\u5feb\uff0c\u589e\u5220\u76f8\u5bf9\u6162\u3002
LinkedList\u5e95\u5c42\u57fa\u4e8e\u53cc\u94fe\u8868\u5b9e\u73b0\u7684\uff0c\u67e5\u8be2\u5143\u7d20\u6162\uff0c\u589e\u5220\u9996\u5c3e\u5143\u7d20\u662f\u975e\u5e38\u5feb\u7684\u3002<\/p>\n\n\n\n
\/**\n    \u62d3\u5c55\uff1aList\u7cfb\u5217\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u6709\uff1a4\u79cd\u3002\n\n    List\u7cfb\u5217\u96c6\u5408\u591a\u4e86\u7d22\u5f15\uff0c\u6240\u4ee5\u591a\u4e86\u4e00\u79cd\u6309\u7167\u7d22\u5f15\u904d\u5386\u96c6\u5408\u7684for\u5faa\u73af\u3002\n\n    List\u904d\u5386\u65b9\u5f0f\uff1a\n        \uff081\uff09for\u5faa\u73af\u3002(\u72ec\u6709\u7684\uff0c\u56e0\u4e3aList\u6709\u7d22\u5f15)\u3002\n        \uff082\uff09\u8fed\u4ee3\u5668\u3002\n        \uff083\uff09foreach\u3002\n        \uff084\uff09JDK 1.8\u65b0\u6280\u672f\u3002\n *\/\npublic class ListDemo02 {\n    public static void main(String[] args) {\n        List<String> lists = new ArrayList<>();\n        lists.add(\"java1\");\n        lists.add(\"java2\");\n        lists.add(\"java3\");\n\n        \/** \uff081\uff09for\u5faa\u73af\u3002 *\/\n        System.out.println(\"-----------------------\");\n\n        for (int i = 0; i < lists.size(); i++) {\n            String ele = lists.get(i);\n            System.out.println(ele);\n        }\n\n\n        \/** \uff082\uff09\u8fed\u4ee3\u5668\u3002 *\/\n        System.out.println(\"-----------------------\");\n        Iterator<String> it = lists.iterator();\n        while (it.hasNext()){\n            String ele = it.next();\n            System.out.println(ele);\n        }\n\n        \/** \uff083\uff09foreach *\/\n        System.out.println(\"-----------------------\");\n        for (String ele : lists) {\n            System.out.println(ele);\n        }\n\n        \/** \uff084\uff09JDK 1.8\u5f00\u59cb\u4e4b\u540e\u7684Lambda\u8868\u8fbe\u5f0f  *\/\n        System.out.println(\"-----------------------\");\n        lists.forEach(s -> {\n            System.out.println(s);\n        });\n\n    }\n}<\/code><\/pre>\n\n\n\n
\/**\n     \u76ee\u6807\uff1aLinkedList\u96c6\u5408\u3002\n\n     Collection\u96c6\u5408\u4f53\u7cfb\u7684\u7279\u70b9:\n         Set\u7cfb\u5217\u96c6\u5408\uff1a \u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u65e0\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u7684\u3002\n             -- HashSet\uff1a\u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u65e0\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u7684\u3002\n             -- LinkedHashSet\uff1a\u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u6709\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u7684\u3002\n         List\u7cfb\u5217\u96c6\u5408\uff1a\u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u6709\u5e8f\uff0c\u53ef\u91cd\u590d\uff0c\u6709\u7d22\u5f15\u7684\u3002\n             -- LinkedList\uff1a \u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u6709\u5e8f\uff0c\u53ef\u91cd\u590d\uff0c\u6709\u7d22\u5f15\u7684\u3002\n             -- Vector\uff1a \u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u6709\u5e8f\uff0c\u53ef\u91cd\u590d\uff0c\u6709\u7d22\u5f15\u7684\u3002\u7ebf\u7a0b\u5b89\u5168\uff08\u6dd8\u6c70\u4e86\uff09\n             -- ArrayList\uff1a \u6dfb\u52a0\u7684\u5143\u7d20\uff0c\u662f\u6709\u5e8f\uff0c\u53ef\u91cd\u590d\uff0c\u6709\u7d22\u5f15\u7684\u3002\n\n     LinkedList\u4e5f\u662fList\u7684\u5b9e\u73b0\u7c7b\uff1a\u5e95\u5c42\u662f\u57fa\u4e8e\u53cc\u94fe\u8868\u7684\uff0c\u589e\u5220\u6bd4\u8f83\u5feb\uff0c\u67e5\u8be2\u6162\uff01\uff01\n     LinkedList\u662f\u652f\u6301\u53cc\u94fe\u8868\uff0c\u5b9a\u4f4d\u524d\u540e\u7684\u5143\u7d20\u662f\u975e\u5e38\u5feb\u7684\uff0c\u589e\u5220\u9996\u5c3e\u7684\u5143\u7d20\u4e5f\u662f\u6700\u5feb\u7684\n     \u6240\u4ee5LinkedList\u9664\u4e86\u62e5\u6709List\u96c6\u5408\u7684\u5168\u90e8\u529f\u80fd\u8fd8\u591a\u4e86\u5f88\u591a\u64cd\u4f5c\u9996\u5c3e\u5143\u7d20\u7684\u7279\u6b8a\u529f\u80fd\uff1a\n         - public void addFirst(E e):\u5c06\u6307\u5b9a\u5143\u7d20\u63d2\u5165\u6b64\u5217\u8868\u7684\u5f00\u5934\u3002\n         - public void addLast(E e):\u5c06\u6307\u5b9a\u5143\u7d20\u6dfb\u52a0\u5230\u6b64\u5217\u8868\u7684\u7ed3\u5c3e\u3002\n         - public E getFirst():\u8fd4\u56de\u6b64\u5217\u8868\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\u3002\n         - public E getLast():\u8fd4\u56de\u6b64\u5217\u8868\u7684\u6700\u540e\u4e00\u4e2a\u5143\u7d20\u3002\n         - public E removeFirst():\u79fb\u9664\u5e76\u8fd4\u56de\u6b64\u5217\u8868\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\u3002\n         - public E removeLast():\u79fb\u9664\u5e76\u8fd4\u56de\u6b64\u5217\u8868\u7684\u6700\u540e\u4e00\u4e2a\u5143\u7d20\u3002\n         - public E pop():\u4ece\u6b64\u5217\u8868\u6240\u8868\u793a\u7684\u5806\u6808\u5904\u5f39\u51fa\u4e00\u4e2a\u5143\u7d20\u3002\n         - public void push(E e):\u5c06\u5143\u7d20\u63a8\u5165\u6b64\u5217\u8868\u6240\u8868\u793a\u7684\u5806\u6808\u3002\n\n    \u5c0f\u7ed3\uff1a\n         LinkedList\u662f\u652f\u6301\u53cc\u94fe\u8868\uff0c\u5b9a\u4f4d\u524d\u540e\u7684\u5143\u7d20\u662f\u975e\u5e38\u5feb\u7684\uff0c\u589e\u5220\u9996\u5c3e\u7684\u5143\u7d20\u4e5f\u662f\u6700\u5feb\u7684\u3002\n         \u6240\u4ee5\u63d0\u4f9b\u4e86\u5f88\u591a\u64cd\u4f5c\u9996\u5c3e\u5143\u7d20\u7684\u7279\u6b8aAPI\u53ef\u7684\u5b9e\u4ee5\u505a\u6808\u548c\u961f\u5217\u73b0\u3002\n\n         \u5982\u679c\u67e5\u8be2\u591a\u800c\u589e\u5220\u5c11\u7528ArrayList\u96c6\u5408\u3002(\u7528\u7684\u6700\u591a\u7684)\n         \u5982\u679c\u67e5\u8be2\u5c11\u800c\u589e\u5220\u9996\u5c3e\u8f83\u591a\u7528LinkedList\u96c6\u5408\u3002\n *\/\npublic class ListDemo03 {\n    public static void main(String[] args) {\n        \/\/ LinkedList\u53ef\u4ee5\u5b8c\u6210\u961f\u5217\u7ed3\u6784\uff0c\u548c\u6808\u7ed3\u6784 \uff08\u53cc\u94fe\u8868\uff09\n        \/\/ 1\u3001\u505a\u4e00\u4e2a\u961f\u5217\uff1a\n        LinkedList<String> queue = new LinkedList<>();\n        \/\/ \u5165\u961f\n        queue.addLast(\"1\u53f7\");\n        queue.addLast(\"2\u53f7\");\n        queue.addLast(\"3\u53f7\");\n        System.out.println(queue);\n        \/\/ \u51fa\u961f\n        \/\/ System.out.println(queue.getFirst());\n        System.out.println(queue.removeFirst());\n        System.out.println(queue.removeFirst());\n        System.out.println(queue);\n\n        \/\/ 2\u3001\u505a\u4e00\u4e2a\u6808\n        LinkedList<String> stack = new LinkedList<>();\n        \/\/ \u5165\u6808 \u538b\u6808 (push)\n        stack.push(\"\u7b2c1\u9897\u5b50\u5f39\");\n        stack.push(\"\u7b2c2\u9897\u5b50\u5f39\");\n        stack.push(\"\u7b2c3\u9897\u5b50\u5f39\");\n        stack.push(\"\u7b2c4\u9897\u5b50\u5f39\");\n        System.out.println(stack);\n\n        \/\/ \u51fa\u6808  \u5f39\u6808 pop\n        System.out.println(stack.pop());\n        System.out.println(stack.pop());\n        System.out.println(stack.pop());\n        System.out.println(stack);\n\n    }\n}<\/code><\/pre>\n\n\n\n
\u4ece\u96c6\u5408\u4e2d\u7684\u4e00\u6279\u5143\u7d20\u4e2d\u627e\u51fa\u67d0\u4e9b\u6570\u636e\u5e76\u5220\u9664\uff0c\u5982\u4f55\u64cd\u4f5c\uff1f\u662f\u5426\u5b58\u5728\u95ee\u9898\u5462 \uff1f<\/p>\n\n\n\n
\u54ea\u4e9b\u904d\u5386\u5b58\u5728\u95ee\u9898\uff1f
\u8fed\u4ee3\u5668\u904d\u5386\u96c6\u5408\u4e14\u76f4\u63a5\u7528\u96c6\u5408\u5220\u9664\u5143\u7d20\u7684\u65f6\u5019\u53ef\u80fd\u51fa\u73b0\u3002
\u589e\u5f3afor\u5faa\u73af\u904d\u5386\u96c6\u5408\u4e14\u76f4\u63a5\u7528\u96c6\u5408\u5220\u9664\u5143\u7d20\u7684\u65f6\u5019\u53ef\u80fd\u51fa\u73b0\u3002<\/p>\n\n\n\n
\u54ea\u79cd\u904d\u5386\u4e14\u5220\u9664\u5143\u7d20\u4e0d\u51fa\u95ee\u9898
\u8fed\u4ee3\u5668\u904d\u5386\u96c6\u5408\u4f46\u662f\u7528\u8fed\u4ee3\u5668\u81ea\u5df1\u7684\u5220\u9664\u65b9\u6cd5\u64cd\u4f5c\u53ef\u4ee5\u89e3\u51b3\u3002
\u4f7f\u7528for\u5faa\u73af\u904d\u5386\u5e76\u5220\u9664\u5143\u7d20\u4e0d\u4f1a\u5b58\u5728\u8fd9\u4e2a\u95ee\u9898\u3002<\/p>\n\n\n\n
\/**\n    \u76ee\u6807\uff1a\u7814\u7a76\u96c6\u5408\u904d\u5386\u5e76\u5220\u9664\u5143\u7d20\u53ef\u80fd\u51fa\u73b0\u7684\uff1a\u5e76\u53d1\u4fee\u6539\u5f02\u5e38\u95ee\u9898\u3002\n *\/\npublic class Test {\n    public static void main(String[] args) {\n        \/\/ 1\u3001\u51c6\u5907\u6570\u636e\n        ArrayList<String> list = new ArrayList<>();\n        list.add(\"\u9ed1\u9a6c\");\n        list.add(\"Java\");\n        list.add(\"Java\");\n        list.add(\"\u8d75\u654f\");\n        list.add(\"\u8d75\u654f\");\n        list.add(\"\u7d20\u7d20\");\n        System.out.println(list);\n        \/\/ [\u9ed1\u9a6c, Java, Java, \u8d75\u654f, \u8d75\u654f, \u7d20\u7d20]\n        \/\/        it\n\n        \/\/ \u9700\u6c42\uff1a\u5220\u9664\u5168\u90e8\u7684Java\u4fe1\u606f\u3002\n        \/\/ a\u3001\u8fed\u4ee3\u5668\u904d\u5386\u5220\u9664\n        Iterator<String> it = list.iterator();\n\/\/        while (it.hasNext()){\n\/\/            String ele = it.next();\n\/\/            if(\"Java\".equals(ele)){\n\/\/                \/\/ \u5220\u9664Java\n\/\/                \/\/ list.remove(ele); \/\/ \u96c6\u5408\u5220\u9664\u4f1a\u51fa\u6bdb\u75c5\n\/\/                it.remove(); \/\/ \u5220\u9664\u8fed\u4ee3\u5668\u6240\u5728\u4f4d\u7f6e\u7684\u5143\u7d20\u503c\uff08\u6ca1\u6bdb\u75c5\uff09\n\/\/            }\n\/\/        }\n\/\/        System.out.println(list);\n\n        \/\/ b\u3001foreach\u904d\u5386\u5220\u9664 (\u4f1a\u51fa\u73b0\u95ee\u9898\uff0c\u8fd9\u79cd\u65e0\u6cd5\u89e3\u51b3\u7684\uff0cforeach\u4e0d\u80fd\u8fb9\u904d\u5386\u8fb9\u5220\u9664\uff0c\u4f1a\u51fabug)\n\/\/        for (String s : list) {\n\/\/            if(\"Java\".equals(s)){\n\/\/                list.remove(s);\n\/\/            }\n\/\/        }\n\n        \/\/ c\u3001lambda\u8868\u8fbe\u5f0f(\u4f1a\u51fa\u73b0\u95ee\u9898\uff0c\u8fd9\u79cd\u65e0\u6cd5\u89e3\u51b3\u7684\uff0cLambda\u904d\u5386\u4e0d\u80fd\u8fb9\u904d\u5386\u8fb9\u5220\u9664\uff0c\u4f1a\u51fabug)\n\/\/        list.forEach(s -> {\n\/\/            if(\"Java\".equals(s)){\n\/\/                list.remove(s);\n\/\/            }\n\/\/        });\n\n        \/\/ d\u3001for\u5faa\u73af(\u8fb9\u904d\u5386\u8fb9\u5220\u9664\u96c6\u5408\u6ca1\u6bdb\u75c5\uff0c\u4f46\u662f\u5fc5\u987b\u4ece\u540e\u9762\u5f00\u59cb\u904d\u5386\u5220\u9664\u624d\u4e0d\u4f1a\u51fa\u73b0\u6f0f\u6389\u5e94\u8be5\u5220\u9664\u7684\u5143\u7d20)\n        for (int i = list.size() - 1; i >= 0 ; i--) {\n            String ele = list.get(i);\n            if(\"Java\".equals(ele)){\n                list.remove(ele);\n            }\n        }\n        System.out.println(list);\n    }\n}<\/code><\/pre>\n\n\n\n
\u6cdb\u578b<\/h2>\n\n\n\n
\u6cdb\u578b\u6982\u8ff0<\/h3>\n\n\n\n
\u6cdb\u578b\uff1a\u662fJDK5\u4e2d\u5f15\u5165\u7684\u7279\u6027\uff0c\u53ef\u4ee5\u5728\u7f16\u8bd1\u9636\u6bb5\u7ea6\u675f\u64cd\u4f5c\u7684\u6570\u636e\u7c7b\u578b\uff0c\u5e76\u8fdb\u884c\u68c0\u67e5\u3002
\u6cdb\u578b\u7684\u683c\u5f0f\uff1a<\u6570\u636e\u7c7b\u578b>; \u6ce8\u610f\uff1a\u6cdb\u578b\u53ea\u80fd\u652f\u6301\u5f15\u7528\u6570\u636e\u7c7b\u578b\u3002
\u96c6\u5408\u4f53\u7cfb\u7684\u5168\u90e8\u63a5\u53e3\u548c\u5b9e\u73b0\u7c7b\u90fd\u662f\u652f\u6301\u6cdb\u578b\u7684\u4f7f\u7528\u7684\u3002
\u6cdb\u578b\u7684\u597d\u5904\uff1a
\u7edf\u4e00\u6570\u636e\u7c7b\u578b\u3002
\u628a\u8fd0\u884c\u65f6\u671f\u7684\u95ee\u9898\u63d0\u524d\u5230\u4e86\u7f16\u8bd1\u671f\u95f4\uff0c\u907f\u514d\u4e86\u5f3a\u5236\u7c7b\u578b\u8f6c\u6362\u53ef\u80fd\u51fa\u73b0\u7684\u5f02\u5e38\uff0c\u56e0\u4e3a\u7f16\u8bd1\u9636\u6bb5\u7c7b\u578b\u5c31\u80fd\u786e\u5b9a\u4e0b\u6765\u3002<\/p>\n\n\n\n
\n\/**\n    \u76ee\u6807\uff1a\u6cdb\u578b\u7684\u6982\u8ff0\u3002\n\n    \u4ec0\u4e48\u662f\u6cdb\u578b\uff1f\n        \u6cdb\u578b\u5c31\u662f\u4e00\u4e2a\u6807\u7b7e\uff1a<\u6570\u636e\u7c7b\u578b>\n        \u6cdb\u578b\u53ef\u4ee5\u5728\u7f16\u8bd1\u9636\u6bb5\u7ea6\u675f\u53ea\u80fd\u64cd\u4f5c\u67d0\u79cd\u6570\u636e\u7c7b\u578b\u3002\n\n    \u6ce8\u610f\uff1a\n        JDK 1.7\u5f00\u59cb\u4e4b\u540e\u540e\u9762\u7684\u6cdb\u578b\u7533\u660e\u53ef\u4ee5\u7701\u7565\u4e0d\u5199\n    \u5c0f\u7ed3\uff1a\n         \u6cdb\u578b\u5c31\u662f\u4e00\u4e2a\u6807\u7b7e\u3002\n         \u6cdb\u578b\u53ef\u4ee5\u5728\u7f16\u8bd1\u9636\u6bb5\u7ea6\u675f\u53ea\u80fd\u64cd\u4f5c\u67d0\u79cd\u6570\u636e\u7c7b\u578b\u3002\n         \u6cdb\u578b\u53ea\u80fd\u652f\u6301\u5f15\u7528\u6570\u636e\u7c7b\u578b\u3002\n *\/\npublic class GenericityDemo {\n    public static void main(String[] args) {\n        List<String> list = new ArrayList<>();\n        list.add(\"Java\");\n        list.add(\"Java2\");\n        \/\/ list.add(23);\n\n        List<String> list1 = new ArrayList();\n        list1.add(\"Java\");\n\/\/        list1.add(23.3);\n\/\/        list1.add(false);\n        list1.add(\"Spring\");\n\n\/\/        for (Object o : list1) {\n\/\/            String ele = (String) o;\n\/\/            System.out.println(ele);\n\/\/        }\n\n        for (String s : list1) {\n            System.out.println(s);\n        }\n\n        System.out.println(\"---------------------\");\n        \/\/ \u5b58\u50a8\u4efb\u610f\u7c7b\u578b\u7684\u5143\u7d20\n        List<Object> list2 = new ArrayList<>();\n        list2.add(23);\n        list2.add(23.3);\n        list2.add(\"Java\");\n\n        \/\/ List<int> list3 = new ArrayList<>();\n        List<Integer> list3 = new ArrayList<>();\n    }\n}<\/code><\/pre>\n\n\n\n
\u6cdb\u578b\u53ef\u4ee5\u5728\u5f88\u591a\u5730\u65b9\u8fdb\u884c\u5b9a\u4e49:
\u7c7b\u540e\u9762->\u6cdb\u578b\u7c7b
\u65b9\u6cd5\u7533\u660e\u4e0a->\u6cdb\u578b\u65b9\u6cd5
\u63a5\u53e3\u540e\u9762->\u578b\u63a5\u53e3<\/p>\n\n\n\n
\u81ea\u5b9a\u4e49\u6cdb\u578b<\/h3>\n\n\n\n
\u5b9a\u4e49\u7c7b\u65f6\u540c\u65f6\u5b9a\u4e49\u4e86\u6cdb\u578b\u7684\u7c7b\u5c31\u662f\u6cdb\u578b\u7c7b\u3002
\u6cdb\u578b\u7c7b\u7684\u683c\u5f0f\uff1a\u4fee\u9970\u7b26 class \u7c7b\u540d<\u6cdb\u578b\u53d8\u91cf>{ }
\u8303\u4f8b\uff1apublic class MyArrayList { }
\u6b64\u5904\u6cdb\u578b\u53d8\u91cfT\u53ef\u4ee5\u968f\u4fbf\u5199\u4e3a\u4efb\u610f\u6807\u8bc6\uff0c\u5e38\u89c1\u7684\u5982E\u3001T\u3001K\u3001V\u7b49\u3002
\u4f5c\u7528\uff1a\u7f16\u8bd1\u9636\u6bb5\u53ef\u4ee5\u6307\u5b9a\u6570\u636e\u7c7b\u578b\uff0c\u7c7b\u4f3c\u4e8e\u96c6\u5408\u7684\u4f5c\u7528\u3002<\/p>\n\n\n\n
import java.util.ArrayList;\n\npublic class MyArrayList<E> {\n    private ArrayList lists = new ArrayList();\n\n    public void add(E e){\n        lists.add(e);\n    }\n\n    public void remove(E e){\n        lists.remove(e);\n    }\n\n    @Override\n    public String toString() {\n        return lists.toString();\n    }\n}\npublic class Test {\n    public static void main(String[] args) {\n        \/\/ \u9700\u6c42\uff1a\u6a21\u62dfArrayList\u5b9a\u4e49\u4e00\u4e2aMyArrayList \uff0c\u5173\u6ce8\u6cdb\u578b\u8bbe\u8ba1\n        MyArrayList<String> list = new MyArrayList<>();\n        list.add(\"Java\");\n        list.add(\"Java\");\n        list.add(\"MySQL\");\n        list.remove(\"MySQL\");\n        System.out.println(list);\n\n        MyArrayList<Integer> list2 = new MyArrayList<>();\n        list2.add(23);\n        list2.add(24);\n        list2.add(25);\n        list2.remove(25);\n        System.out.println(list2);\n    }\n}<\/code><\/pre>\n\n\n\n
\u6cdb\u578b\u65b9\u6cd5<\/h3>\n\n\n\n
\u5b9a\u4e49\u65b9\u6cd5\u65f6\u540c\u65f6\u5b9a\u4e49\u4e86\u6cdb\u578b\u7684\u65b9\u6cd5\u5c31\u662f\u6cdb\u578b\u65b9\u6cd5\u3002
\u6cdb\u578b\u65b9\u6cd5\u7684\u683c\u5f0f\uff1a\u4fee\u9970\u7b26 <\u6cdb\u578b\u53d8\u91cf> \u65b9\u6cd5\u8fd4\u56de\u503c \u65b9\u6cd5\u540d\u79f0(\u5f62\u53c2\u5217\u8868){}
\u8303\u4f8b\uff1a public void show(T t) { }
\u4f5c\u7528\uff1a\u65b9\u6cd5\u4e2d\u53ef\u4ee5\u4f7f\u7528\u6cdb\u578b\u63a5\u6536\u4e00\u5207\u5b9e\u9645\u7c7b\u578b\u7684\u53c2\u6570\uff0c\u65b9\u6cd5\u66f4\u5177\u5907\u901a\u7528\u6027\u3002<\/p>\n\n\n\n
\/**\n    \u76ee\u6807\uff1a\u81ea\u5b9a\u4e49\u6cdb\u578b\u65b9\u6cd5\u3002\n\n    \u4ec0\u4e48\u662f\u6cdb\u578b\u65b9\u6cd5\uff1f\n        \u5b9a\u4e49\u4e86\u6cdb\u578b\u7684\u65b9\u6cd5\u5c31\u662f\u6cdb\u578b\u65b9\u6cd5\u3002\n\n    \u6cdb\u578b\u65b9\u6cd5\u7684\u5b9a\u4e49\u683c\u5f0f:\n        \u4fee\u9970\u7b26 <\u6cdb\u578b\u53d8\u91cf> \u8fd4\u56de\u503c\u7c7b\u578b \u65b9\u6cd5\u540d\u79f0(\u5f62\u53c2\u5217\u8868){\n\n        }\n        \u6ce8\u610f\uff1a\u65b9\u6cd5\u5b9a\u4e49\u4e86\u662f\u4ec0\u4e48\u6cdb\u578b\u53d8\u91cf\uff0c\u540e\u9762\u5c31\u53ea\u80fd\u7528\u4ec0\u4e48\u6cdb\u578b\u53d8\u91cf\u3002\n        \u6cdb\u578b\u7c7b\u7684\u6838\u5fc3\u601d\u60f3\uff1a\u662f\u628a\u51fa\u73b0\u6cdb\u578b\u53d8\u91cf\u7684\u5730\u65b9\u5168\u90e8\u66ff\u6362\u6210\u4f20\u8f93\u7684\u771f\u5b9e\u6570\u636e\u7c7b\u578b\u3002\n\n    \u9700\u6c42\uff1a\u7ed9\u4f60\u4efb\u4f55\u4e00\u4e2a\u7c7b\u578b\u7684\u6570\u7ec4\uff0c\u90fd\u80fd\u8fd4\u56de\u5b83\u7684\u5185\u5bb9\u3002Arrays.toString(\u6570\u7ec4)\u7684\u529f\u80fd\uff01\n\n    \u5c0f\u7ed3\uff1a\n        \u6cdb\u578b\u65b9\u6cd5\u53ef\u4ee5\u8ba9\u65b9\u6cd5\u66f4\u7075\u6d3b\u7684\u63a5\u6536\u6570\u636e\uff0c\u53ef\u4ee5\u505a\u901a\u7528\u6280\u672f\uff01\n *\/\npublic class GenericDemo {\n    public static void main(String[] args) {\n        String[] names = {\"\u5c0f\u7490\", \"\u84c9\u5bb9\", \"\u5c0f\u4f55\"};\n        printArray(names);\n\n        Integer[] ages = {10, 20, 30};\n        printArray(ages);\n\n        Integer[] ages2 = getArr(ages);\n        String[]  names2 = getArr(names);\n    }\n\n    public static <T> T[] getArr(T[] arr){\n        return arr;\n    }\n\n    public static <T> void printArray(T[] arr){\n        if(arr != null){\n            StringBuilder sb = new StringBuilder(\"[\");\n            for (int i = 0; i < arr.length; i++) {\n                sb.append(arr[i]).append(i == arr.length - 1 ? \"\" : \", \");\n            }\n            sb.append(\"]\");\n            System.out.println(sb);\n        }else {\n            System.out.println(arr);\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
\u6cdb\u578b\u63a5\u53e3<\/h3>\n\n\n\n
\u4f7f\u7528\u4e86\u6cdb\u578b\u5b9a\u4e49\u7684\u63a5\u53e3\u5c31\u662f\u6cdb\u578b\u63a5\u53e3\u3002
\u6cdb\u578b\u63a5\u53e3\u7684\u683c\u5f0f\uff1a\u4fee\u9970\u7b26 interface \u63a5\u53e3\u540d\u79f0<\u6cdb\u578b\u53d8\u91cf>{}
\u8303\u4f8b\uff1a public interface Data{}
\u4f5c\u7528\uff1a\u6cdb\u578b\u63a5\u53e3\u53ef\u4ee5\u8ba9\u5b9e\u73b0\u7c7b\u9009\u62e9\u5f53\u524d\u529f\u80fd\u9700\u8981\u64cd\u4f5c\u7684\u6570\u636e\u7c7b\u578b<\/p>\n\n\n\n
public interface Data<E> {\n    void add(E e);\n    void delete(int id);\n    void update(E e);\n    E queryById(int id);\n}\npublic class StudentData implements Data<Student>{\n    @Override\n    public void add(Student student) {\n\n    }\n\n    @Override\n    public void delete(int id) {\n\n    }\n\n    @Override\n    public void update(Student student) {\n\n    }\n\n    @Override\n    public Student queryById(int id) {\n        return null;\n    }\n}<\/code><\/pre>\n\n\n\n
\u6cdb\u578b\u901a\u914d\u7b26<\/h3>\n\n\n\n
\u901a\u914d\u7b26 ? \u53ef\u4ee5\u5728\u201c\u4f7f\u7528\u6cdb\u578b\u201d\u7684\u65f6\u5019\u4ee3\u8868\u4e00\u5207\u7c7b\u578b\u3002
E T K V \u662f\u5728\u5b9a\u4e49\u6cdb\u578b\u7684\u65f6\u5019\u4f7f\u7528\u7684\u3002
? extends Car: ?\u5fc5\u987b\u662fCar\u6216\u8005\u5176\u5b50\u7c7b \u6cdb\u578b\u4e0a\u9650
? super Car \uff1a ?\u5fc5\u987b\u662fCar\u6216\u8005\u5176\u7236\u7c7b \u6cdb\u578b\u4e0b\u9650<\/p>\n\n\n\n
\/**\n    \u76ee\u6807\uff1a\u6cdb\u578b\u901a\u914d\u7b26\u3002?\n\n    \u9700\u6c42\uff1a\u5f00\u53d1\u4e00\u4e2a\u6781\u54c1\u98de\u8f66\u7684\u6e38\u620f\uff0c\u6240\u6709\u7684\u6c7d\u8f66\u90fd\u80fd\u4e00\u8d77\u53c2\u4e0e\u6bd4\u8d5b\u3002\n\n    \u6ce8\u610f\uff1a\n        \u867d\u7136BMW\u548cBENZ\u90fd\u7ee7\u627f\u4e86Car\n        \u4f46\u662fArrayList<BMW>\u548cArrayList<BENZ>\u4e0eArrayList<Car>\u6ca1\u6709\u5173\u7cfb\u7684\uff01!\n    \u901a\u914d\u7b26\uff1a\uff1f\n        \uff1f\u53ef\u4ee5\u5728\u201c\u4f7f\u7528\u6cdb\u578b\u201d\u7684\u65f6\u5019\u4ee3\u8868\u4e00\u5207\u7c7b\u578b\u3002\n        E T K V \u662f\u5728\u5b9a\u4e49\u6cdb\u578b\u7684\u65f6\u5019\u4f7f\u7528\u7684\u3002\n    \u6cdb\u578b\u7684\u4e0a\u4e0b\u9650\uff1a\n        \uff1f extends Car : ?\u5fc5\u987b\u662fCar\u6216\u8005\u5176\u5b50\u7c7b  \u6cdb\u578b\u4e0a\u9650\n        ? super Car \uff1a\uff1f\u5fc5\u987b\u662fCar\u6216\u8005\u5176\u7236\u7c7b   \u6cdb\u578b\u4e0b\u9650\n    \u5c0f\u7ed3\uff1a\n        \u901a\u914d\u7b26\uff1a\uff1f\n        \uff1f\u53ef\u4ee5\u5728\u201c\u4f7f\u7528\u6cdb\u578b\u201d\u7684\u65f6\u5019\u4ee3\u8868\u4e00\u5207\u7c7b\u578b\u3002\n\n *\/\npublic class GenericDemo {\n    public static void main(String[] args) {\n        ArrayList<BMW> bmws = new ArrayList<>();\n        bmws.add(new BMW());\n        bmws.add(new BMW());\n        bmws.add(new BMW());\n        go(bmws);\n\n        ArrayList<BENZ> benzs = new ArrayList<>();\n        benzs.add(new BENZ());\n        benzs.add(new BENZ());\n        benzs.add(new BENZ());\n        go(benzs);\n\n        ArrayList<Dog> dogs = new ArrayList<>();\n        dogs.add(new Dog());\n        dogs.add(new Dog());\n        dogs.add(new Dog());\n        \/\/ go(dogs);\n    }\n\n    \/**\n       \u6240\u6709\u8f66\u6bd4\u8d5b\n     *\/\n    public static void go(ArrayList<? extends Car> cars){\n    }\n}\n\nclass Dog{\n\n}\n\nclass  BENZ extends Car{\n}\n\nclass BMW extends Car{\n}\n\n\/\/ \u7236\u7c7b\nclass Car{\n}<\/code><\/pre>\n\n\n\n
 Set\u7cfb\u5217<\/h2>\n\n\n\n
Set\u7cfb\u5217\u96c6\u5408\u7279\u70b9
\u65e0\u5e8f\uff1a\u5b58\u53d6\u987a\u5e8f\u4e0d\u4e00\u81f4
\u4e0d\u91cd\u590d\uff1a\u53ef\u4ee5\u53bb\u9664\u91cd\u590d
\u65e0\u7d22\u5f15\uff1a\u6ca1\u6709\u5e26\u7d22\u5f15\u7684\u65b9\u6cd5\uff0c\u6240\u4ee5\u4e0d\u80fd\u4f7f\u7528\u666e\u901afor\u5faa\u73af\u904d\u5386\uff0c\u4e5f\u4e0d\u80fd\u901a\u8fc7\u7d22\u5f15\u6765\u83b7\u53d6\u5143\u7d20\u3002
Set\u96c6\u5408\u5b9e\u73b0\u7c7b\u7279\u70b9
HashSet : \u65e0\u5e8f\u3001\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\u3002
LinkedHashSet\uff1a\u6709\u5e8f\u3001\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\u3002
TreeSet\uff1a\u6392\u5e8f\u3001\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\u3002<\/p>\n\n\n\n
import java.util.HashSet;\nimport java.util.Set;\npublic class SetDemo1 {\n    public static void main(String[] args) {\n        \/\/ \u770b\u770bSet\u7cfb\u5217\u96c6\u5408\u7684\u7279\u70b9\uff1a HashSet LinkedHashSet TreeSet\n        \/\/\n        Set<String> sets = new HashSet<>(); \/\/ \u4e00\u884c\u7ecf\u5178\u4ee3\u7801  \u65e0\u5e8f\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\n        \/\/ Set<String> sets = new LinkedHashSet<>(); \/\/ \u6709\u5e8f  \u4e0d\u91cd\u590d \u65e0\u7d22\u5f15\n        sets.add(\"MySQL\");\n        sets.add(\"MySQL\");\n        sets.add(\"Java\");\n        sets.add(\"Java\");\n        sets.add(\"HTML\");\n        sets.add(\"HTML\");\n        sets.add(\"SpringBoot\");\n        sets.add(\"SpringBoot\");\n        System.out.println(sets);\n    }\n}<\/code><\/pre>\n\n\n\n
 Set\u96c6\u5408\u7684\u5e95\u5c42\u539f\u7406\u662f\u4ec0\u4e48\u6837\u7684
JDK8\u4e4b\u524d\u7684\uff0c\u54c8\u5e0c\u8868\uff1a\u5e95\u5c42\u4f7f\u7528\u6570\u7ec4+\u94fe\u8868\u7ec4\u6210
JDK8\u5f00\u59cb\u540e\uff0c\u54c8\u5e0c\u8868\uff1a\u5e95\u5c42\u91c7\u7528\u6570\u7ec4+\u94fe\u8868+\u7ea2\u9ed1\u6811\u7ec4\u6210<\/p>\n\n\n\n
\u54c8\u5e0c\u8868\u7684\u8be6\u7ec6\u6d41\u7a0b
1\u521b\u5efa\u4e00\u4e2a\u9ed8\u8ba4\u957f\u5ea616\uff0c\u9ed8\u8ba4\u52a0\u8f7d\u56e0\u4e3a0.75\u7684\u6570\u7ec4\uff0c\u6570\u7ec4\u540dtable
2\u6839\u636e\u5143\u7d20\u7684\u54c8\u5e0c\u503c\u8ddf\u6570\u7ec4\u7684\u957f\u5ea6\u8ba1\u7b97\u51fa\u5e94\u5b58\u5165\u7684\u4f4d\u7f6e
3\u5224\u65ad\u5f53\u524d\u4f4d\u7f6e\u662f\u5426\u4e3anull\uff0c\u5982\u679c\u662fnull\u76f4\u63a5\u5b58\u5165\uff0c\u5982\u679c\u4f4d\u7f6e\u4e0d\u4e3anull\uff0c\u8868\u793a\u6709\u5143\u7d20\uff0c \u5219\u8c03\u7528equals\u65b9\u6cd5\u6bd4\u8f83\u5c5e\u6027\u503c\uff0c\u5982\u679c\u4e00\u6837\uff0c\u5219\u4e0d\u5b58\uff0c\u5982\u679c\u4e0d\u4e00\u6837\uff0c\u5219\u5b58\u5165\u6570\u7ec4\u3002
4\u5f53\u6570\u7ec4\u5b58\u6ee1\u523016*0.75=12\u65f6\uff0c\u5c31\u81ea\u52a8\u6269\u5bb9\uff0c\u6bcf\u6b21\u6269\u5bb9\u539f\u5148\u7684\u4e24\u500d<\/p>\n\n\n\n
HashSet<\/h3>\n\n\n\n
HashSet\u53bb\u91cd\u590d\u539f\u7406\u89e3\u6790
1\u521b\u5efa\u4e00\u4e2a\u9ed8\u8ba4\u957f\u5ea616\u7684\u6570\u7ec4\uff0c\u6570\u7ec4\u540dtable
2\u6839\u636e\u5143\u7d20\u7684\u54c8\u5e0c\u503c\u8ddf\u6570\u7ec4\u7684\u957f\u5ea6\u6c42\u4f59\u8ba1\u7b97\u51fa\u5e94\u5b58\u5165\u7684\u4f4d\u7f6e\uff08\u54c8\u5e0c\u7b97\u6cd5\uff09
3\u5224\u65ad\u5f53\u524d\u4f4d\u7f6e\u662f\u5426\u4e3anull\uff0c\u5982\u679c\u662fnull\u76f4\u63a5\u5b58\u5165
4\u5982\u679c\u4f4d\u7f6e\u4e0d\u4e3anull\uff0c\u8868\u793a\u6709\u5143\u7d20\uff0c\u5219\u8c03\u7528equals\u65b9\u6cd5\u6bd4\u8f83
5\u5982\u679c\u4e00\u6837\uff0c\u5219\u4e0d\u5b58\uff0c\u5982\u679c\u4e0d\u4e00\u6837\uff0c\u5219\u5b58\u5165\u6570\u7ec4
\u7ed3\u8bba\uff1a\u5982\u679c\u5e0c\u671bSet\u96c6\u5408\u8ba4\u4e3a2\u4e2a\u5185\u5bb9\u4e00\u6837\u7684\u5bf9\u8c61\u662f\u91cd\u590d\u7684\uff0c\u5fc5\u987b\u91cd\u5199\u5bf9\u8c61\u7684hashCode()\u548cequals()\u65b9\u6cd5<\/p>\n\n\n\n
Example:
\u521b\u5efa\u4e00\u4e2a\u5b58\u50a8\u5b66\u751f\u5bf9\u8c61\u7684\u96c6\u5408\uff0c\u5b58\u50a8\u591a\u4e2a\u5b66\u751f\u5bf9\u8c61\uff0c\u4f7f\u7528\u7a0b\u5e8f\u5b9e\u73b0\u5728\u63a7\u5236\u53f0\u904d\u5386\u8be5\u96c6\u5408\uff0c\u8981\u6c42\uff1a\u5b66\u751f\u5bf9\u8c61\u7684\u6210\u5458\u53d8\u91cf\u503c\u76f8\u540c\uff0c\u6211\u4eec\u5c31\u8ba4\u4e3a\u662f\u540c\u4e00\u4e2a\u5bf9\u8c61
\u5b9a\u4e49\u5b66\u751f\u7c7b\uff0c\u521b\u5efaHashSet\u96c6\u5408\u5bf9\u8c61, \u521b\u5efa\u5b66\u751f\u5bf9\u8c61
\u628a\u5b66\u751f\u6dfb\u52a0\u5230\u96c6\u5408
\u5728\u5b66\u751f\u7c7b\u4e2d\u91cd\u5199\u4e24\u4e2a\u65b9\u6cd5\uff0chashCode()\u548cequals()\uff0c\u81ea\u52a8\u751f\u6210\u5373\u53ef
\u904d\u5386\u96c6\u5408(\u589e\u5f3afor)<\/p>\n\n\n\n
\/\/Student.java\npackage com.itheima.d1_collection_set;\n\nimport java.util.Objects;\n\npublic class  Student {\n    private String name;\n    private int age;\n    private char sex;\n\n    public Student() {\n    }\n\n    public Student(String name, int age, char sex) {\n        this.name = name;\n        this.age = age;\n        this.sex = sex;\n    }\n\n    public String getName() {\n        return name;\n    }\n\n    public void setName(String name) {\n        this.name = name;\n    }\n\n    public int getAge() {\n        return age;\n    }\n\n    public void setAge(int age) {\n        this.age = age;\n    }\n\n    public char getSex() {\n        return sex;\n    }\n\n    public void setSex(char sex) {\n        this.sex = sex;\n    }\n\n    \/**\n       \u53ea\u89812\u4e2a\u5bf9\u8c61\u5185\u5bb9\u4e00\u6837\uff0c\u7ed3\u679c\u4e00\u5b9a\u662ftrue\n     * @param o\n     * @return\n     *\/\n    @Override\n    public boolean equals(Object o) {\n        if (this == o) return true;\n        if (o == null || getClass() != o.getClass()) return false;\n        Student student = (Student) o;\n        return age == student.age && sex == student.sex && Objects.equals(name, student.name);\n    }\n\n    @Override\n    public int hashCode() {\n        return Objects.hash(name, age, sex);\n    }\n\n    @Override\n    public String toString() {\n        return \"Student{\" +\n                \"name='\" + name + '\\'' +\n                \", age=\" + age +\n                \", sex=\" + sex +\n                '}';\n    }\n}\n\n\/**\n    \u76ee\u6807\uff1a\u8ba9Set\u96c6\u5408\u628a\u91cd\u590d\u5185\u5bb9\u7684\u5bf9\u8c61\u53bb\u6389\u4e00\u4e2a\uff08\u53bb\u91cd\u590d\uff09\n *\/\npublic class SetDemo3 {\n    public static void main(String[] args) {\n        \/\/ Set\u96c6\u5408\u53bb\u91cd\u590d\u539f\u56e0\uff1a\u5148\u5224\u65ad\u54c8\u5e0c\u503c\u7b97\u51fa\u6765\u7684\u5b58\u50a8\u4f4d\u7f6e\u662f\u5426\u76f8\u540c \u518d\u5224\u65adequals\n        Set<Student> sets = new HashSet<>();\n\n        Student s1 = new Student(\"\u65e0\u6059\", 20, '\u7537');\n        Student s2 = new Student(\"\u65e0\u6059\", 20, '\u7537');\n        Student s3 = new Student(\"\u5468\u96c4\", 21, '\u7537');\n        System.out.println(s1.hashCode());\n        System.out.println(s2.hashCode());\n        System.out.println(s3.hashCode());\n\n        sets.add(s1);\n        sets.add(s2);\n        sets.add(s3);\n\n        System.out.println(sets);\n    }\n}\n\/\/\u5982\u679c\u4e0d\u91cd\u5199hashCode()\u51fd\u6570\u5219s1,s2hashcode\u4e0d\u540c\uff0c\u65e0\u6cd5\u5224\u5b9a\u4e3a\u91cd\u590d\u3002\n\/\/Alt+insert\u5feb\u901f\u81ea\u52a8\u751f\u6210hashcode()\u548cequals()\u51fd\u6570<\/code><\/pre>\n\n\n\n
HashSet\u904d\u5386<\/p>\n\n\n\n
public static void main(String[] args){\n\t\t\n\t\tSet<String> set = new HashSet<String>();\n\t\tset.add(\"a1\");\n\t\tset.add(\"b2\");\n\t\tset.add(\"c3\");\n\t\tset.add(\"d4\");\n\t\t\n\t\t\/\/ \u521d\u59cb\u5316\u4e00\u4e2aHashSet\u96c6\u5408\n\t\tSystem.out.println(\"--------\u539fHashSet\u96c6\u5408----------\");\n\t\tSystem.out.println(set);\n\t\tSystem.out.println();\n\t\t\n\t\t\/\/ \u65b9\u6cd5\u4e00\uff1a\n\t\tIterator<String> iterator = set.iterator();\n\t\tSystem.out.println(\"--------\u8fed\u4ee3\u5668\u904d\u5386HashSet----------\");\n\t\twhile(iterator.hasNext()){\n\t\t\tSystem.out.print(iterator.next()+\",\");\n\t\t}\n\t\t\n\t\t\n\t\t\/\/ \u65b9\u6cd5\u4e8c\uff1a\n\t\tSystem.out.println(\"--------\u52a0\u5f3afor\u5faa\u73af\u904d\u5386---------\");\n\t\tfor (String item : set) {\n\t\t\tSystem.out.print(item+\",\");\n\t\t}\n\t}<\/code><\/pre>\n\n\n\n
LinkedHashSet<\/h3>\n\n\n\n
LinkedHashSet\u96c6\u5408\u6982\u8ff0\u548c\u7279\u70b9
\u6709\u5e8f\u3001\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\u3002
\u8fd9\u91cc\u7684\u6709\u5e8f\u6307\u7684\u662f\u4fdd\u8bc1\u5b58\u50a8\u548c\u53d6\u51fa\u7684\u5143\u7d20\u987a\u5e8f\u4e00\u81f4
\u539f\u7406\uff1a\u5e95\u5c42\u6570\u636e\u7ed3\u6784\u662f\u4f9d\u7136\u54c8\u5e0c\u8868\uff0c\u53ea\u662f\u6bcf\u4e2a\u5143\u7d20\u53c8\u989d\u5916\u7684\u591a\u4e86\u4e00\u4e2a\u53cc\u94fe\u8868\u7684\u673a\u5236\u8bb0\u5f55\u5b58\u50a8\u7684\u987a\u5e8f\u3002<\/p>\n\n\n\n
TreeSet<\/h3>\n\n\n\n
TreeSet\u96c6\u5408\u6982\u8ff0\u548c\u7279\u70b9
\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\u3001\u53ef\u6392\u5e8f
\u53ef\u6392\u5e8f\uff1a\u6309\u7167\u5143\u7d20\u7684\u5927\u5c0f\u9ed8\u8ba4\u5347\u5e8f\uff08\u6709\u5c0f\u5230\u5927\uff09\u6392\u5e8f\u3002
TreeSet\u96c6\u5408\u5e95\u5c42\u662f\u57fa\u4e8e\u7ea2\u9ed1\u6811\u7684\u6570\u636e\u7ed3\u6784\u5b9e\u73b0\u6392\u5e8f\u7684\uff0c\u589e\u5220\u6539\u67e5\u6027\u80fd\u90fd\u8f83\u597d\u3002
\u6ce8\u610f\uff1aTreeSet\u96c6\u5408\u662f\u4e00\u5b9a\u8981\u6392\u5e8f\u7684\uff0c\u53ef\u4ee5\u5c06\u5143\u7d20\u6309\u7167\u6307\u5b9a\u7684\u89c4\u5219\u8fdb\u884c\u6392\u5e8f\u3002<\/p>\n\n\n\n
\u6ce8\u610f\u533a\u5206\u6709\u5e8f\u4e0e\u6392\u5e8f\uff01<\/p>\n\n\n\n
TreeSet\u96c6\u5408\u9ed8\u8ba4\u7684\u89c4\u5219
\u5bf9\u4e8e\u6570\u503c\u7c7b\u578b\uff1aInteger , Double\uff0c\u5b98\u65b9\u9ed8\u8ba4\u6309\u7167\u5927\u5c0f\u8fdb\u884c\u5347\u5e8f\u6392\u5e8f\u3002
\u5bf9\u4e8e\u5b57\u7b26\u4e32\u7c7b\u578b\uff1a\u9ed8\u8ba4\u6309\u7167\u9996\u5b57\u7b26\u7684\u7f16\u53f7\u5347\u5e8f\u6392\u5e8f\u3002
\u5bf9\u4e8e\u81ea\u5b9a\u4e49\u7c7b\u578b\u5982Student\u5bf9\u8c61\uff0cTreeSet\u65e0\u6cd5\u76f4\u63a5\u6392\u5e8f\u3002
\u7ed3\u8bba\uff1a\u60f3\u8981\u4f7f\u7528TreeSet\u5b58\u50a8\u81ea\u5b9a\u4e49\u7c7b\u578b\uff0c\u9700\u8981\u5236\u5b9a\u6392\u5e8f\u89c4\u5219<\/p>\n\n\n\n
TreeSet\u96c6\u5408\u5b58\u50a8\u5bf9\u8c61\u7684\u7684\u65f6\u5019\u67092\u79cd\u65b9\u5f0f\u53ef\u4ee5\u8bbe\u8ba1\u81ea\u5b9a\u4e49\u6bd4\u8f83\u89c4\u5219
\u65b9\u5f0f\u4e00
\u8ba9\u81ea\u5b9a\u4e49\u7684\u7c7b\uff08\u5982\u5b66\u751f\u7c7b\uff09\u5b9e\u73b0Comparable\u63a5\u53e3\u91cd\u5199\u91cc\u9762\u7684compareTo\u65b9\u6cd5\u6765\u5b9a\u5236\u6bd4\u8f83\u89c4\u5219\u3002
\u65b9\u5f0f\u4e8c
TreeSet\u96c6\u5408\u6709\u53c2\u6570\u6784\u9020\u5668\uff0c\u53ef\u4ee5\u8bbe\u7f6eComparator\u63a5\u53e3\u5bf9\u5e94\u7684\u6bd4\u8f83\u5668\u5bf9\u8c61\uff0c\u6765\u5b9a\u5236\u6bd4\u8f83\u89c4\u5219\u3002
\u4e24\u79cd\u65b9\u5f0f\u4e2d\uff0c\u5173\u4e8e\u8fd4\u56de\u503c\u7684\u89c4\u5219\uff1a
\u5982\u679c\u8ba4\u4e3a\u7b2c\u4e00\u4e2a\u5143\u7d20\u5927\u4e8e\u7b2c\u4e8c\u4e2a\u5143\u7d20\u8fd4\u56de\u6b63\u6574\u6570\u5373\u53ef\u3002
\u5982\u679c\u8ba4\u4e3a\u7b2c\u4e00\u4e2a\u5143\u7d20\u5c0f\u4e8e\u7b2c\u4e8c\u4e2a\u5143\u7d20\u8fd4\u56de\u8d1f\u6574\u6570\u5373\u53ef\u3002
\u5982\u679c\u8ba4\u4e3a\u7b2c\u4e00\u4e2a\u5143\u7d20\u7b49\u4e8e\u7b2c\u4e8c\u4e2a\u5143\u7d20\u8fd4\u56de0\u5373\u53ef\uff0c\u6b64\u65f6Treeset\u96c6\u5408\u53ea\u4f1a\u4fdd\u7559\u4e00\u4e2a\u5143\u7d20\uff0c\u8ba4\u4e3a\u4e24\u8005\u91cd\u590d\u3002
\u6ce8\u610f\uff1a\u5982\u679cTreeSet\u96c6\u5408\u5b58\u50a8\u7684\u5bf9\u8c61\u6709\u5b9e\u73b0\u6bd4\u8f83\u89c4\u5219\uff0c\u96c6\u5408\u4e5f\u81ea\u5e26\u6bd4\u8f83\u5668\uff0c\u9ed8\u8ba4\u4f7f\u7528\u96c6\u5408\u81ea\u5e26\u7684\u6bd4\u8f83\u5668\u6392\u5e8f<\/p>\n\n\n\n
public class Apple implements Comparable<Apple>{\n    private String name;\n    private String color;\n    private double price;\n    private int weight;\n\n    public Apple() {\n    }\n\n    public Apple(String name, String color, double price, int weight) {\n        this.name = name;\n        this.color = color;\n        this.price = price;\n        this.weight = weight;\n    }\n\n    public String getName() {\n        return name;\n    }\n\n    public void setName(String name) {\n        this.name = name;\n    }\n\n    public String getColor() {\n        return color;\n    }\n\n    public void setColor(String color) {\n        this.color = color;\n    }\n\n    public double getPrice() {\n        return price;\n    }\n\n    public void setPrice(double price) {\n        this.price = price;\n    }\n\n    public int getWeight() {\n        return weight;\n    }\n\n    public void setWeight(int weight) {\n        this.weight = weight;\n    }\n\n    @Override\n    public String toString() {\n        return \"Apple{\" +\n                \"name='\" + name + '\\'' +\n                \", color='\" + color + '\\'' +\n                \", price=\" + price +\n                \", weight=\" + weight +\n                '}';\n    }\n\n    \/**\n      \u65b9\u5f0f\u4e00\uff1a\u7c7b\u81ea\u5b9a\u4e49\u6bd4\u8f83\u89c4\u5219\n      o1.compareTo(o2)\n     * @param o\n     * @return\n     *\/\n    @Override\n    public int compareTo(Apple o) {\n        \/\/ \u6309\u7167\u91cd\u91cf\u8fdb\u884c\u6bd4\u8f83\u7684\n        return this.weight - o.weight ; \/\/ \u53bb\u91cd\u91cd\u91cf\u91cd\u590d\u7684\u5143\u7d20\n        \/\/ return this.weight - o.weight >= 0 ? 1 : -1; \/\/ \u4fdd\u7559\u91cd\u91cf\u91cd\u590d\u7684\u5143\u7d20\n    }\n}\n\n\/**\n   \u76ee\u6807\uff1a\u89c2\u5bdfTreeSet\u5bf9\u4e8e\u6709\u503c\u7279\u6027\u7684\u6570\u636e\u5982\u4f55\u6392\u5e8f\u3002\n        \u5b66\u4f1a\u5bf9\u81ea\u5b9a\u4e49\u7c7b\u578b\u7684\u5bf9\u8c61\u8fdb\u884c\u6307\u5b9a\u89c4\u5219\u6392\u5e8f\n *\/\npublic class  SetDemo5 {\n    public static void main(String[] args) {\n        Set<Integer> sets = new TreeSet<>(); \/\/ \u4e0d\u91cd\u590d \u65e0\u7d22\u5f15 \u53ef\u6392\u5e8f\n        sets.add(23);\n        sets.add(24);\n        sets.add(12);\n        sets.add(8);\n        System.out.println(sets);\n\n        Set<String> sets1 = new TreeSet<>(); \/\/ \u4e0d\u91cd\u590d \u65e0\u7d22\u5f15 \u53ef\u6392\u5e8f\n        sets1.add(\"Java\");\n        sets1.add(\"Java\");\n        sets1.add(\"angela\");\n        sets1.add(\"\u9ed1\u9a6c\");\n        sets1.add(\"Java\");\n        sets1.add(\"About\");\n        sets1.add(\"Python\");\n        sets1.add(\"UI\");\n        sets1.add(\"UI\");\n        System.out.println(sets1);\n\n        System.out.println(\"------------------------------\");\n        \/\/ \u65b9\u5f0f\u4e8c\uff1a\u96c6\u5408\u81ea\u5e26\u6bd4\u8f83\u5668\u5bf9\u8c61\u8fdb\u884c\u89c4\u5219\u5b9a\u5236\n        \/\/\n\/\/        Set<Apple> apples = new TreeSet<>(new Comparator<Apple>() {\n\/\/            @Override\n\/\/            public int compare(Apple o1, Apple o2) {\n\/\/                \/\/ return o1.getWeight() - o2.getWeight(); \/\/ \u5347\u5e8f\n\/\/                \/\/ return o2.getWeight() - o1.getWeight(); \/\/ \u964d\u5e8f\n\/\/                \/\/ \u6ce8\u610f\uff1a\u6d6e\u70b9\u578b\u5efa\u8bae\u76f4\u63a5\u4f7f\u7528Double.compare\u8fdb\u884c\u6bd4\u8f83\n\/\/                \/\/ return Double.compare(o1.getPrice() , o2.getPrice()); \/\/ \u5347\u5e8f\n\/\/                return Double.compare(o2.getPrice() , o1.getPrice()); \/\/ \u964d\u5e8f\n\/\/            }\n\/\/        });\n\n        Set<Apple> apples = new TreeSet<>(( o1,  o2) ->  Double.compare(o2.getPrice() , o1.getPrice())  );\n        apples.add(new Apple(\"\u7ea2\u5bcc\u58eb\", \"\u7ea2\u8272\", 9.9, 500));\n        apples.add(new Apple(\"\u9752\u82f9\u679c\", \"\u7eff\u8272\", 15.9, 300));\n        apples.add(new Apple(\"\u7eff\u82f9\u679c\", \"\u9752\u8272\", 29.9, 400));\n        apples.add(new Apple(\"\u9ec4\u82f9\u679c\", \"\u9ec4\u8272\", 9.8, 500));\n        System.out.println(apples);\n    }\n}\n<\/code><\/pre>\n\n\n\n
\u4e09\u79cdSet\u904d\u5386\u6bd4\u8f83<\/p>\n\n\n\n
public static void main(String[] args) {\n    \/\/ HashSet, LinkedHashSet\n    List<String> list = new LinkedList<>();\n    list.add(\"\u6c5f\");\n    list.add(\"\u5c71\");\n    list.add(\"\u5982\");\n    list.add(\"\u6b64\");\n    list.add(\"\u591a\");\n    list.add(\"\u5a07\");\n\n    \/\/ TreeSet, \u56e0\u4e3a\u4f7f\u7528\u6c49\u5b57\u7684\u8bdd\uff0c\u4e0d\u5bb9\u6613\u770b\u51faTreeSet\u7684\u6392\u5e8f\u6548\u679c\n    List<String> list01 = new LinkedList<>();\n    list01.add(\"J\");\n    list01.add(\"S\");\n    list01.add(\"R\");\n    list01.add(\"C\");\n    list01.add(\"D\");\n    list01.add(\"J\");\n\n    HashSet<String> set = new HashSet<>(list);\n    System.out.println(\"----------------------HashSet----------------------\");\n    \/\/ for\u5faa\u73af\u904d\u5386\u65b9\u5f0f\n    for (String s : set){\n        \/\/System.out.println(s);\n    }\n    \/\/ \u8fed\u4ee3\u5668\u904d\u5386\u65b9\u5f0f\n    Iterator<String> ite = set.iterator();\n    while(ite.hasNext()){\n        System.out.println(ite.next());\n    }\n    \/\/ foreach\u904d\u5386\u65b9\u5f0f\n    set.forEach(ites->{\n        \/\/System.out.println(ites);\n    });\n\n    LinkedHashSet<String> set01 = new LinkedHashSet<>(list);\n    System.out.println(\"-------------------LinkedHashSet-------------------\");\n    \/\/for\u5faa\u73af\u904d\u5386\u65b9\u5f0f\n    for (String s : set01){\n        \/\/System.out.println(s);\n    }\n    \/\/ \u8fed\u4ee3\u5668\u904d\u5386\u65b9\u5f0f\n    Iterator<String> ite01 = set01.iterator();\n    while(ite01.hasNext()){\n        System.out.println(ite01.next());\n    }\n    \/\/ foreach\u904d\u5386\u65b9\u5f0f\n    set01.forEach(ites->{\n        \/\/System.out.println(ites);\n    });\n\n    TreeSet<String> set02 = new TreeSet<>(list01);\n    System.out.println(\"----------------------TreeSet----------------------\");\n    \/\/ for\u5faa\u73af\u904d\u5386\u65b9\u5f0f\n    for (String s : set02){\n        \/\/System.out.println(s);\n    }\n    \/\/ \u8fed\u4ee3\u5668\u904d\u5386\u65b9\u5f0f\n    Iterator<String> ite02 = set02.iterator();\n    while(ite02.hasNext()){\n        System.out.println(ite02.next());\n    }\n    \/\/ foreach\u904d\u5386\u65b9\u5f0f\n    set02.forEach(ites->{\n        \/\/System.out.println(ites);\n    });\n}\n\n\/\/\u8fd0\u884c\u7ed3\u679c\n\n----------------------HashSet----------------------\n\u5c71\n\u5982\n\u6b64\n\u5a07\n\u591a\n\u6c5f\n-------------------LinkedHashSet-------------------\n\u6c5f\n\u5c71\n\u5982\n\u6b64\n\u591a\n\u5a07\n----------------------TreeSet----------------------\nC\nD\nJ\nR\nS\n\nProcess finished with exit code 0\n<\/code><\/pre>\n\n\n\n
\u53ef\u53d8\u53c2\u6570<\/h2>\n\n\n\n
import java.util.Arrays;\n\n\/**\n    \u76ee\u6807\uff1a\u53ef\u53d8\u53c2\u6570\u3002\n\n    \u53ef\u53d8\u53c2\u6570\u7528\u5728\u5f62\u53c2\u4e2d\u53ef\u4ee5\u63a5\u6536\u591a\u4e2a\u6570\u636e\u3002\n    \u53ef\u53d8\u53c2\u6570\u7684\u683c\u5f0f\uff1a\u6570\u636e\u7c7b\u578b...\u53c2\u6570\u540d\u79f0\n\n    \u53ef\u53d8\u53c2\u6570\u7684\u4f5c\u7528\uff1a\n         \u4f20\u8f93\u53c2\u6570\u975e\u5e38\u7075\u6d3b\uff0c\u65b9\u4fbf\u3002\n         \u53ef\u4ee5\u4e0d\u4f20\u8f93\u53c2\u6570\u3002\n         \u53ef\u4ee5\u4f20\u8f93\u4e00\u4e2a\u53c2\u6570\u3002\n         \u53ef\u4ee5\u4f20\u8f93\u591a\u4e2a\u53c2\u6570\u3002\n         \u53ef\u4ee5\u4f20\u8f93\u4e00\u4e2a\u6570\u7ec4\u3002\n\n     \u53ef\u53d8\u53c2\u6570\u5728\u65b9\u6cd5\u5185\u90e8\u672c\u8d28\u4e0a\u5c31\u662f\u4e00\u4e2a\u6570\u7ec4\u3002\n     \u53ef\u53d8\u53c2\u6570\u7684\u6ce8\u610f\u4e8b\u9879\uff1a\n         1.\u4e00\u4e2a\u5f62\u53c2\u5217\u8868\u4e2d\u53ef\u53d8\u53c2\u6570\u53ea\u80fd\u6709\u4e00\u4e2a\uff01\uff01\n         2.\u53ef\u53d8\u53c2\u6570\u5fc5\u987b\u653e\u5728\u5f62\u53c2\u5217\u8868\u7684\u6700\u540e\u9762\uff01\uff01\n     \u5c0f\u7ed3\uff1a\n        \u8bb0\u4f4f\u3002\n *\/\npublic class MethodDemo {\n    public static void main(String[] args) {\n\n        sum(); \/\/ 1\u3001\u4e0d\u4f20\u53c2\u6570\n        sum(10); \/\/ 2\u3001\u53ef\u4ee5\u4f20\u8f93\u4e00\u4e2a\u53c2\u6570\n        sum(10, 20, 30); \/\/ 3\u3001\u53ef\u4ee5\u4f20\u8f93\u591a\u4e2a\u53c2\u6570\n        sum(new int[]{10, 20, 30, 40, 50}); \/\/ 4\u3001\u53ef\u4ee5\u4f20\u8f93\u4e00\u4e2a\u6570\u7ec4\n    }\n\n    \/**\n       \u6ce8\u610f\uff1a\u4e00\u4e2a\u5f62\u53c2\u5217\u8868\u4e2d\u53ea\u80fd\u6709\u4e00\u4e2a\u53ef\u53d8\u53c2\u6570,\u53ef\u53d8\u53c2\u6570\u5fc5\u987b\u653e\u5728\u5f62\u53c2\u5217\u8868\u7684\u6700\u540e\u9762\n     * @param nums\n     *\/\n    public static void sum(  int...nums){\n        \/\/ \u6ce8\u610f\uff1a\u53ef\u53d8\u53c2\u6570\u5728\u65b9\u6cd5\u5185\u90e8\u5176\u5b9e\u5c31\u662f\u4e00\u4e2a\u6570\u7ec4\u3002 nums\n        System.out.println(\"\u5143\u7d20\u4e2a\u6570\uff1a\" + nums.length);\n        System.out.println(\"\u5143\u7d20\u5185\u5bb9\uff1a\" + Arrays.toString(nums));\n    }\n}<\/code><\/pre>\n\n\n\n
Collections\u5de5\u5177\u7c7b<\/h2>\n\n\n\n
ava.utils.Collections:\u662f\u96c6\u5408\u5de5\u5177\u7c7b
\u4f5c\u7528\uff1aCollections\u5e76\u4e0d\u5c5e\u4e8e\u96c6\u5408\uff0c\u662f\u7528\u6765\u64cd\u4f5c\u96c6\u5408\u7684\u5de5\u5177\u7c7b\u3002<\/p>\n\n\n\n
Collections\u5e38\u7528\u7684API<\/p>\n\n\n\n
\u65b9\u6cd5\u540d\u79f0<\/td>\u8bf4\u660e<\/td><\/tr>
public static <T> boolean addAll(Collection<? super T> c, T... elements)<\/td>\u7ed9\u96c6\u5408\u5bf9\u8c61\u6279\u91cf\u6dfb\u52a0\u5143\u7d20<\/td><\/tr>
public static void shuffle(List<?> list) <\/td>\u6253\u4e71List\u96c6\u5408\u5143\u7d20\u7684\u987a\u5e8f<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\u65b9\u6cd5\u540d\u79f0<\/td>\u8bf4\u660e<\/td><\/tr>
public static <T> void sort(List<T> list)<\/td>\u5c06\u96c6\u5408\u4e2d\u5143\u7d20\u6309\u7167\u9ed8\u8ba4\u89c4\u5219\u6392\u5e8f<\/td><\/tr>
public static void sort(List list\uff0cComparator c)<\/td>\u5c06\u96c6\u5408\u4e2d\u5143\u7d20\u6309\u7167\u6307\u5b9a\u89c4\u5219\u6392\u5e8f<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
tips:Shift+F6\u540c\u6b65\u6539\u53d8\u91cf\u540d<\/p>\n\n\n\n
\/**\n    \u76ee\u6807\uff1aCollections\u5de5\u5177\u7c7b\u7684\u4f7f\u7528\u3002\n\n    java.utils.Collections:\u662f\u96c6\u5408\u5de5\u5177\u7c7b\n    Collections\u5e76\u4e0d\u5c5e\u4e8e\u96c6\u5408\uff0c\u662f\u7528\u6765\u64cd\u4f5c\u96c6\u5408\u7684\u5de5\u5177\u7c7b\u3002\n    Collections\u6709\u51e0\u4e2a\u5e38\u7528\u7684API:\n         - public static <T> boolean addAll(Collection<? super T> c, T... elements)\n             \u7ed9\u96c6\u5408\u5bf9\u8c61\u6279\u91cf\u6dfb\u52a0\u5143\u7d20\uff01\n         - public static void shuffle(List<?> list) :\u6253\u4e71\u96c6\u5408\u987a\u5e8f\u3002\n         - public static <T> void sort(List<T> list):\u5c06\u96c6\u5408\u4e2d\u5143\u7d20\u6309\u7167\u9ed8\u8ba4\u89c4\u5219\u6392\u5e8f\u3002\n         - public static <T> void sort(List<T> list\uff0cComparator<? super T> c):\u5c06\u96c6\u5408\u4e2d\u5143\u7d20\u6309\u7167\u6307\u5b9a\u89c4\u5219\u6392\u5e8f\u3002\n *\/\npublic class CollectionsDemo01 {\n    public static void main(String[] args) {\n        List<String> names = new ArrayList<>();\n        \/\/names.add(\"\u695a\u7559\u9999\");\n        \/\/names.add(\"\u80e1\u94c1\u82b1\");\n        \/\/names.add(\"\u5f20\u65e0\u5fcc\");\n        \/\/names.add(\"\u9646\u5c0f\u51e4\");\n        Collections.addAll(names, \"\u695a\u7559\u9999\",\"\u80e1\u94c1\u82b1\", \"\u5f20\u65e0\u5fcc\",\"\u9646\u5c0f\u51e4\");\n        System.out.println(names);\n\n        \/\/ 2\u3001public static void shuffle(List<?> list) :\u6253\u4e71\u96c6\u5408\u987a\u5e8f\u3002\n        Collections.shuffle(names);\n        System.out.println(names);\n\n        \/\/ 3\u3001 public static <T> void sort(List<T> list):\u5c06\u96c6\u5408\u4e2d\u5143\u7d20\u6309\u7167\u9ed8\u8ba4\u89c4\u5219\u6392\u5e8f\u3002 \uff08\u6392\u503c\u7279\u6027\u7684\u5143\u7d20\uff09\n        List<Integer> list = new ArrayList<>();\n        Collections.addAll(list, 12, 23, 2, 4);\n        System.out.println(list);\n        Collections.sort(list);\n        System.out.println(list);\n    }\n}<\/code><\/pre>\n\n\n\n
\/\/Apple.java\npublic class Apple implements Comparable<Apple>{\n    private String name;\n    private String color;\n    private double price;\n    private int weight;\n\n    public Apple() {\n    }\n\n    public Apple(String name, String color, double price, int weight) {\n        this.name = name;\n        this.color = color;\n        this.price = price;\n        this.weight = weight;\n    }\n\n    public String getName() {\n        return name;\n    }\n\n    public void setName(String name) {\n        this.name = name;\n    }\n\n    public String getColor() {\n        return color;\n    }\n\n    public void setColor(String color) {\n        this.color = color;\n    }\n\n    public double getPrice() {\n        return price;\n    }\n\n    public void setPrice(double price) {\n        this.price = price;\n    }\n\n    public int getWeight() {\n        return weight;\n    }\n\n    public void setWeight(int weight) {\n        this.weight = weight;\n    }\n\n    @Override\n    public String toString() {\n        return \"Apple{\" +\n                \"name='\" + name + '\\'' +\n                \", color='\" + color + '\\'' +\n                \", price=\" + price +\n                \", weight=\" + weight +\n                '}';\n    }\n\n    \/**\n      \u65b9\u5f0f\u4e00\uff1a\u7c7b\u81ea\u5b9a\u4e49\u6bd4\u8f83\u89c4\u5219\n      o1.compareTo(o2)\n     * @param o\n     * @return\n     *\/\n    @Override\n    public int compareTo(Apple o) {\n        \/\/ \u6309\u7167\u91cd\u91cf\u8fdb\u884c\u6bd4\u8f83\u7684\n        return this.weight - o.weight ; \/\/ List\u96c6\u5b58\u50a8\u76f8\u540c\u5927\u5c0f\u7684\u5143\u7d20 \u4f1a\u4fdd\u7559\uff01\n    }\n}\n\/\/CollectionsDemo02.java\nimport java.util.*;\n\n\/**\n    \u76ee\u6807\uff1a\u5f15\u7528\u6570\u636e\u7c7b\u578b\u7684\u6392\u5e8f\u3002\n\n    \u5b57\u7b26\u4e32\u6309\u7167\u9996\u5b57\u7b26\u7684\u7f16\u53f7\u5347\u5e8f\u6392\u5e8f\uff01\n\n    \u81ea\u5b9a\u4e49\u7c7b\u578b\u7684\u6bd4\u8f83\u65b9\u6cd5API:Collections\n         - public static <T> void sort(List<T> list):\n               \u5c06\u96c6\u5408\u4e2d\u5143\u7d20\u6309\u7167\u9ed8\u8ba4\u89c4\u5219\u6392\u5e8f\u3002\n               \u5bf9\u4e8e\u81ea\u5b9a\u4e49\u7684\u5f15\u7528\u7c7b\u578b\u7684\u6392\u5e8f\u4eba\u5bb6\u6839\u672c\u4e0d\u77e5\u9053\u600e\u4e48\u6392\uff0c\u76f4\u63a5\u62a5\u9519\uff01\n\n         - public static <T> void sort(List<T> list\uff0cComparator<? super T> c):\n                \u5c06\u96c6\u5408\u4e2d\u5143\u7d20\u6309\u7167\u6307\u5b9a\u89c4\u5219\u6392\u5e8f,\u81ea\u5e26\u6bd4\u8f83\u5668\n *\/\npublic class CollectionsDemo02 {\n    public static void main(String[] args) {\n        List<Apple> apples = new ArrayList<>(); \/\/ \u53ef\u4ee5\u91cd\u590d\uff01\n        apples.add(new Apple(\"\u7ea2\u5bcc\u58eb\", \"\u7ea2\u8272\", 9.9, 500));\n        apples.add(new Apple(\"\u9752\u82f9\u679c\", \"\u7eff\u8272\", 15.9, 300));\n        apples.add(new Apple(\"\u7eff\u82f9\u679c\", \"\u9752\u8272\", 29.9, 400));\n        apples.add(new Apple(\"\u9ec4\u82f9\u679c\", \"\u9ec4\u8272\", 9.8, 500));\n\n\/\/        Collections.sort(apples); \/\/ \u65b9\u6cd5\u4e00\uff1a\u53ef\u4ee5\u7684\uff0cApple\u7c7b\u5df2\u7ecf\u91cd\u5199\u4e86\u6bd4\u8f83\u89c4\u5219\n\/\/        System.out.println(apples);\n\n        \/\/ \u65b9\u5f0f\u4e8c\uff1asort\u65b9\u6cd5\u81ea\u5e26\u6bd4\u8f83\u5668\u5bf9\u8c61\n\/\/        Collections.sort(apples, new Comparator<Apple>() {\n\/\/            @Override\n\/\/            public int compare(Apple o1, Apple o2) {\n\/\/                return Double.compare(o1.getPrice() , o2.getPrice()); \/\/ \u6309\u7167\u4ef7\u683c\u6392\u5e8f\uff01\uff01\n\/\/            }\n\/\/        });\n\n        Collections.sort(apples, ( o1,  o2) ->  Double.compare(o1.getPrice() , o2.getPrice()) );\n        System.out.println(apples);\n\n    }\n}<\/code><\/pre>\n\n\n\n
Example\uff1a\u6597\u5730\u4e3b\u6e38\u620f<\/p>\n\n\n\n
\u9700\u6c42\uff1a\u5728\u542f\u52a8\u6e38\u620f\u623f\u95f4\u7684\u65f6\u5019\uff0c\u5e94\u8be5\u63d0\u524d\u51c6\u5907\u597d54\u5f20\u724c\uff0c\u5b8c\u6210\u6d17\u724c\u3001\u53d1\u724c\u3001\u724c\u6392\u5e8f\u3001\u903b\u8f91\u3002
\u5206\u6790\uff1a
1\u5f53\u7cfb\u7edf\u542f\u52a8\u7684\u540c\u65f6\u9700\u8981\u51c6\u5907\u597d\u6570\u636e\u7684\u65f6\u5019\uff0c\u5c31\u53ef\u4ee5\u7528\u9759\u6001\u4ee3\u7801\u5757\u4e86
2\u6d17\u724c\u5c31\u662f\u6253\u4e71\u724c\u7684\u987a\u5e8f
3\u5b9a\u4e49\u4e09\u4e2a\u73a9\u5bb6\u3001\u4f9d\u6b21\u53d1\u51fa51\u5f20\u724c
4\u7ed9\u73a9\u5bb6\u7684\u724c\u8fdb\u884c\u6392\u5e8f(\u62d3\u5c55)
5\u8f93\u51fa\u6bcf\u4e2a\u73a9\u5bb6\u7684\u724c\u6570\u636e<\/p>\n\n\n\n
\/\/card.java\npublic class Card {\n    private String size;\n    private String color;\n    private int index; \/\/ \u724c\u7684\u771f\u6b63\u5927\u5c0f\n\n    public Card(){\n    }\n\n    public Card(String size, String color, int index) {\n        this.size = size;\n        this.color = color;\n        this.index = index;\n    }\n\n    public String getSize() {\n        return size;\n    }\n\n    public void setSize(String size) {\n        this.size = size;\n    }\n\n    public String getColor() {\n        return color;\n    }\n\n    public void setColor(String color) {\n        this.color = color;\n    }\n\n    public int getIndex() {\n        return index;\n    }\n\n    public void setIndex(int index) {\n        this.index = index;\n    }\n\n    @Override\n    public String toString() {\n        return size + color;\n    }\n}\n\/\/GameDemo.java\nimport java.util.*;\n\n\/**\n    \u76ee\u6807\uff1a\u6597\u5730\u4e3b\u6e38\u620f\u7684\u6848\u4f8b\u5f00\u53d1\u3002\n\n    \u4e1a\u52a1\u9700\u6c42\u5206\u6790:\n        \u6597\u5730\u4e3b\u7684\u505a\u724c, \u6d17\u724c, \u53d1\u724c, \u6392\u5e8f\uff08\u62d3\u5c55\u77e5\u8bc6\uff09, \u770b\u724c\u3002\n        \u4e1a\u52a1: \u603b\u5171\u670954\u5f20\u724c\u3002\n        \u70b9\u6570: \"3\",\"4\",\"5\",\"6\",\"7\",\"8\",\"9\",\"10\",\"J\",\"Q\",\"K\",\"A\",\"2\"\n        \u82b1\u8272: \"\u2660\", \"\u2665\", \"\u2663\", \"\u2666\"\n        \u5927\u5c0f\u738b: \"\ud83d\udc72\" , \"\ud83c\udccf\"\n        \u70b9\u6570\u5206\u522b\u8981\u7ec4\u54084\u79cd\u82b1\u8272\uff0c\u5927\u5c0f\u738b\u5404\u4e00\u5f20\u3002\n        \u6597\u5730\u4e3b\uff1a\u53d1\u51fa51\u5f20\u724c\uff0c\u5269\u4e0b3\u5f20\u4f5c\u4e3a\u5e95\u724c\u3002\n\n    \u529f\u80fd\uff1a\n        1.\u505a\u724c\u3002\n        2.\u6d17\u724c\u3002\n        3.\u5b9a\u4e493\u4e2a\u73a9\u5bb6\n        4.\u53d1\u724c\u3002\n        5.\u6392\u5e8f\uff08\u62d3\u5c55\uff0c\u4e86\u89e3\uff0c\u4f5c\u4e1a\uff09\n        6.\u770b\u724c\n *\/\npublic class GameDemo {\n    \/**\n      1\u3001\u5b9a\u4e49\u4e00\u4e2a\u9759\u6001\u7684\u96c6\u5408\u5b58\u50a854\u5f20\u724c\u5bf9\u8c61\n     *\/\n     public static List<Card> allCards = new ArrayList<>();\n\n    \/**\n      2\u3001\u505a\u724c\uff1a\u5b9a\u4e49\u9759\u6001\u4ee3\u7801\u5757\u521d\u59cb\u5316\u724c\u6570\u636e\n     *\/\n    static {\n        \/\/ 3\u3001\u5b9a\u4e49\u70b9\u6570\uff1a\u4e2a\u6570\u786e\u5b9a\uff0c\u7c7b\u578b\u786e\u5b9a\uff0c\u4f7f\u7528\u6570\u7ec4\n        String[] sizes = {\"3\",\"4\",\"5\",\"6\",\"7\",\"8\",\"9\",\"10\",\"J\",\"Q\",\"K\",\"A\",\"2\"};\n        \/\/ 4\u3001\u5b9a\u4e49\u82b1\u8272\uff1a\u4e2a\u6570\u786e\u5b9a\uff0c\u7c7b\u578b\u786e\u5b9a\uff0c\u4f7f\u7528\u6570\u7ec4\n        String[] colors = {\"\u2660\", \"\u2665\", \"\u2663\", \"\u2666\"};\n        \/\/ 5\u3001\u7ec4\u5408\u70b9\u6570\u548c\u82b1\u8272\n        int index = 0; \/\/ \u8bb0\u5f55\u724c\u7684\u5927\u5c0f\n        for (String size : sizes) {\n            index++;\n            for (String color : colors) {\n                \/\/ 6\u3001\u5c01\u88c5\u6210\u4e00\u4e2a\u724c\u5bf9\u8c61\u3002\n                Card c = new Card(size, color, index);\n                \/\/ 7\u3001\u5b58\u5165\u5230\u96c6\u5408\u5bb9\u5668\u4e2d\u53bb\n                allCards.add(c);\n            }\n        }\n        \/\/ 8 \u5927\u5c0f\u738b\u5b58\u5165\u5230\u96c6\u5408\u5bf9\u8c61\u4e2d\u53bb \"\ud83d\udc72\" , \"\ud83c\udccf\"\n        Card c1 = new Card(\"\" ,  \"\ud83c\udccf\", ++index);\n        Card c2 = new Card(\"\" ,  \"\ud83d\udc72\",++index);\n        Collections.addAll(allCards , c1 , c2);\n        System.out.println(\"\u65b0\u724c\uff1a\" + allCards);\n    }\n\n    public static void main(String[] args) {\n        \/\/ 9\u3001\u6d17\u724c\n        Collections.shuffle(allCards);\n        System.out.println(\"\u6d17\u724c\u540e\uff1a\" + allCards);\n\n        \/\/ 10\u3001\u53d1\u724c\uff08\u5b9a\u4e49\u4e09\u4e2a\u73a9\u5bb6\uff0c\u6bcf\u4e2a\u73a9\u5bb6\u7684\u724c\u4e5f\u662f\u4e00\u4e2a\u96c6\u5408\u5bb9\u5668\uff09\n        List<Card> linhuchong = new ArrayList<>();\n        List<Card> jiumozhi = new ArrayList<>();\n        List<Card> renyingying = new ArrayList<>();\n\n        \/\/ 11\u3001\u5f00\u59cb\u53d1\u724c\uff08\u4ece\u724c\u96c6\u5408\u4e2d\u53d1\u51fa51\u5f20\u724c\u7ed9\u4e09\u4e2a\u73a9\u5bb6\uff0c\u5269\u4f593\u5f20\u4f5c\u4e3a\u5e95\u724c\uff09\n        \/\/ allCards = [\ud83c\udccf, A\u2660, 5\u2665, 2\u2660, 2\u2663, Q\u2663, \ud83d\udc72, Q\u2660 ...\n        \/\/    i        0  1   2   3   4   5    6  7      %  3\n        for (int i = 0; i < allCards.size() - 3; i++) {\n            \/\/ \u5148\u62ff\u5230\u5f53\u524d\u724c\u5bf9\u8c61\n            Card c = allCards.get(i);\n            if(i % 3 == 0) {\n                \/\/ \u8bf7\u963f\u51b2\u63a5\u724c\n                linhuchong.add(c);\n            }else if(i % 3 == 1){\n                \/\/ \u8bf7\u963f\u9e20\n                jiumozhi.add(c);\n            }else if(i % 3 == 2){\n                \/\/ \u8bf7\u76c8\u76c8\u63a5\u724c\n                renyingying.add(c);\n            }\n        }\n\n        \/\/ 12\u3001\u62ff\u5230\u6700\u540e\u4e09\u5f20\u5e95\u724c(\u628a\u6700\u540e\u4e09\u5f20\u724c\u622a\u53d6\u6210\u4e00\u4e2a\u5b50\u96c6\u5408)\n        List<Card> lastThreeCards = allCards.subList(allCards.size() - 3 , allCards.size());\n\n        \/\/ 13\u3001\u7ed9\u73a9\u5bb6\u7684\u724c\u6392\u5e8f\uff08\u4ece\u5927\u5230\u5c0f \u53ef\u4ee5\u81ea\u5df1\u5148\u8bd5\u8bd5\u600e\u4e48\u5b9e\u73b0\uff09\n        sortCards(linhuchong);\n        sortCards(jiumozhi);\n        sortCards(renyingying);\n\n        \/\/ 14\u3001\u8f93\u51fa\u73a9\u5bb6\u7684\u724c\uff1a\n        System.out.println(\"\u554a\u51b2\uff1a\" + linhuchong);\n        System.out.println(\"\u554a\u9e20\uff1a\" + jiumozhi);\n        System.out.println(\"\u76c8\u76c8\uff1a\" + renyingying);\n        System.out.println(\"\u4e09\u5f20\u5e95\u724c\uff1a\" + lastThreeCards);\n    }\n\n    \/**\n       \u7ed9\u724c\u6392\u5e8f\n     * @param cards\n     *\/\n    private static void sortCards(List<Card> cards) {\n        \/\/ cards = [J\u2665, A\u2666, 3\u2665, \ud83c\udccf, 5\u2666, Q\u2665, 2\u2665\n        Collections.sort(cards, new Comparator<Card>() {\n            @Override\n            public int compare(Card o1, Card o2) {\n                \/\/ o1 = J\u2665\n                \/\/ o2 = A\u2666\n                \/\/ \u77e5\u9053\u724c\u7684\u5927\u5c0f\uff0c\u624d\u53ef\u4ee5\u6307\u5b9a\u89c4\u5219\n                return o2.getIndex() - o1.getIndex();\n            }\n        });\n    }\n\n}<\/code><\/pre>\n\n\n\n
Map<\/h2>\n\n\n\n
Map\u96c6\u5408\u662f\u4e00\u79cd\u53cc\u5217\u96c6\u5408\uff0c\u6bcf\u4e2a\u5143\u7d20\u5305\u542b\u4e24\u4e2a\u6570\u636e\u3002
Map\u96c6\u5408\u7684\u6bcf\u4e2a\u5143\u7d20\u7684\u683c\u5f0f\uff1akey=value(\u952e\u503c\u5bf9\u5143\u7d20)\u3002
Map\u96c6\u5408\u4e5f\u88ab\u79f0\u4e3a\u201c\u952e\u503c\u5bf9\u96c6\u5408\u201d
Collection\u96c6\u5408\u7684\u683c\u5f0f: [\u5143\u7d201,\u5143\u7d202,\u5143\u7d203..]
Map\u96c6\u5408\u7684\u5b8c\u6574\u683c\u5f0f\uff1a{key1=value1 , key2=value2 , key3=value3 , \u2026}<\/p>\n\n\n\n
Map\u96c6\u5408\u4f53\u7cfb\u7279\u70b9:
Map\u96c6\u5408\u7684\u7279\u70b9\u90fd\u662f\u7531\u952e\u51b3\u5b9a\u7684\u3002
Map\u96c6\u5408\u7684\u952e\u662f\u65e0\u5e8f,\u4e0d\u91cd\u590d\u7684\uff0c\u65e0\u7d22\u5f15\u7684\uff0c\u503c\u4e0d\u505a\u8981\u6c42\uff08\u53ef\u4ee5\u91cd\u590d\uff09\u3002
Map\u96c6\u5408\u540e\u9762\u91cd\u590d\u7684\u952e\u5bf9\u5e94\u7684\u503c\u4f1a\u8986\u76d6\u524d\u9762\u91cd\u590d\u952e\u7684\u503c\u3002
Map\u96c6\u5408\u7684\u952e\u503c\u5bf9\u90fd\u53ef\u4ee5\u4e3anull<\/p>\n\n\n\n
Map\u96c6\u5408\u5b9e\u73b0\u7c7b\u7279\u70b9:
HashMap:\u5143\u7d20\u6309\u7167\u952e\u662f\u65e0\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\uff0c\u503c\u4e0d\u505a\u8981\u6c42\u3002\uff08\u4e0eMap\u4f53\u7cfb\u4e00\u81f4\uff09
LinkedHashMap:\u5143\u7d20\u6309\u7167\u952e\u662f\u6709\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\uff0c\u503c\u4e0d\u505a\u8981\u6c42\u3002
TreeMap\uff1a\u5143\u7d20\u6309\u7167\u5efa\u662f\u6392\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u7684\uff0c\u503c\u4e0d\u505a\u8981\u6c42<\/p>\n\n\n\n
Map\u96c6\u5408
Map\u662f\u53cc\u5217\u96c6\u5408\u7684\u7956\u5b97\u63a5\u53e3\uff0c\u5b83\u7684\u529f\u80fd\u662f\u5168\u90e8\u53cc\u5217\u96c6\u5408\u90fd\u53ef\u4ee5\u7ee7\u627f\u4f7f\u7528\u7684<\/p>\n\n\n\n
\u65b9\u6cd5\u540d\u79f0<\/td>\u8bf4\u660e<\/td><\/tr>
V put(K key,V value)<\/td>\u6dfb\u52a0\u5143\u7d20<\/td><\/tr>
V remove(Object key)<\/td>\u6839\u636e\u952e\u5220\u9664\u952e\u503c\u5bf9\u5143\u7d20<\/td><\/tr>
void clear()<\/td>\u79fb\u9664\u6240\u6709\u7684\u952e\u503c\u5bf9\u5143\u7d20<\/td><\/tr>
boolean containsKey(Object key)<\/td>\u5224\u65ad\u96c6\u5408\u662f\u5426\u5305\u542b\u6307\u5b9a\u7684\u952e<\/td><\/tr>
boolean containsValue(Object value)<\/td>\u5224\u65ad\u96c6\u5408\u662f\u5426\u5305\u542b\u6307\u5b9a\u7684\u503c<\/td><\/tr>
boolean isEmpty()<\/td>\u5224\u65ad\u96c6\u5408\u662f\u5426\u4e3a\u7a7a<\/td><\/tr>
int size()<\/td>\u96c6\u5408\u7684\u957f\u5ea6\uff0c\u4e5f\u5c31\u662f\u96c6\u5408\u4e2d\u952e\u503c\u5bf9\u7684\u4e2a\u6570<\/td><\/tr><\/tbody><\/table>
Map API<\/figcaption><\/figure>\n\n\n\n
\/**\n    \u76ee\u6807\uff1aMap\u96c6\u5408\u7684\u5e38\u7528API(\u91cd\u70b9\u4e2d\u7684\u91cd\u70b9)\n     - public V put(K key, V value):  \u628a\u6307\u5b9a\u7684\u952e\u4e0e\u6307\u5b9a\u7684\u503c\u6dfb\u52a0\u5230Map\u96c6\u5408\u4e2d\u3002\n     - public V remove(Object key): \u628a\u6307\u5b9a\u7684\u952e \u6240\u5bf9\u5e94\u7684\u952e\u503c\u5bf9\u5143\u7d20 \u5728Map\u96c6\u5408\u4e2d\u5220\u9664\uff0c\u8fd4\u56de\u88ab\u5220\u9664\u5143\u7d20\u7684\u503c\u3002\n     - public V get(Object key) \u6839\u636e\u6307\u5b9a\u7684\u952e\uff0c\u5728Map\u96c6\u5408\u4e2d\u83b7\u53d6\u5bf9\u5e94\u7684\u503c\u3002\n     - public Set<K> keySet(): \u83b7\u53d6Map\u96c6\u5408\u4e2d\u6240\u6709\u7684\u952e\uff0c\u5b58\u50a8\u5230Set\u96c6\u5408\u4e2d\u3002\n     - public Set<Map.Entry<K,V>> entrySet(): \u83b7\u53d6\u5230Map\u96c6\u5408\u4e2d\u6240\u6709\u7684\u952e\u503c\u5bf9\u5bf9\u8c61\u7684\u96c6\u5408(Set\u96c6\u5408)\u3002\n     - public boolean containKey(Object key):\u5224\u65ad\u8be5\u96c6\u5408\u4e2d\u662f\u5426\u6709\u6b64\u952e\u3002\n     - public boolean containValue(Object value):\u5224\u65ad\u8be5\u96c6\u5408\u4e2d\u662f\u5426\u6709\u6b64\u503c\u3002\n *\/\npublic class MapDemo {\n    public static void main(String[] args) {\n        \/\/ 1.\u6dfb\u52a0\u5143\u7d20: \u65e0\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u3002\n        Map<String , Integer> maps = new HashMap<>();\n        maps.put(\"iphoneX\",10);\n        maps.put(\"\u5a03\u5a03\",20);\n        maps.put(\"iphoneX\",100);\/\/  Map\u96c6\u5408\u540e\u9762\u91cd\u590d\u7684\u952e\u5bf9\u5e94\u7684\u5143\u7d20\u4f1a\u8986\u76d6\u524d\u9762\u91cd\u590d\u7684\u6574\u4e2a\u5143\u7d20\uff01\n        maps.put(\"huawei\",100);\n        maps.put(\"\u751f\u6d3b\u7528\u54c1\",10);\n        maps.put(\"\u624b\u8868\",10);\n        \/\/ {huawei=100, \u624b\u8868=10, \u751f\u6d3b\u7528\u54c1=10, iphoneX=100, \u5a03\u5a03=20}\n        System.out.println(maps);\n\n        \/\/ 2.\u6e05\u7a7a\u96c6\u5408\n\/\/        maps.clear();\n\/\/        System.out.println(maps);\n\n        \/\/ 3.\u5224\u65ad\u96c6\u5408\u662f\u5426\u4e3a\u7a7a\uff0c\u4e3a\u7a7a\u8fd4\u56detrue ,\u53cd\u4e4b\uff01\n        System.out.println(maps.isEmpty());\n\n        \/\/ 4.\u6839\u636e\u952e\u83b7\u53d6\u5bf9\u5e94\u503c:public V get(Object key)\n        Integer key = maps.get(\"huawei\");\n        System.out.println(key);\n        System.out.println(maps.get(\"\u751f\u6d3b\u7528\u54c1\")); \/\/ 10\n        System.out.println(maps.get(\"\u751f\u6d3b\u7528\u54c12\")); \/\/ null\n\n        \/\/ 5.\u6839\u636e\u952e\u5220\u9664\u6574\u4e2a\u5143\u7d20\u3002(\u5220\u9664\u952e\u4f1a\u8fd4\u56de\u952e\u7684\u503c)\n        System.out.println(maps.remove(\"iphoneX\"));\n        System.out.println(maps);\n\n        \/\/ 6.\u5224\u65ad\u662f\u5426\u5305\u542b\u67d0\u4e2a\u952e \uff0c\u5305\u542b\u8fd4\u56detrue ,\u53cd\u4e4b\n        System.out.println(maps.containsKey(\"\u5a03\u5a03\"));  \/\/ true\n        System.out.println(maps.containsKey(\"\u5a03\u5a032\"));  \/\/ false\n        System.out.println(maps.containsKey(\"iphoneX\")); \/\/ false\n\n        \/\/ 7.\u5224\u65ad\u662f\u5426\u5305\u542b\u67d0\u4e2a\u503c\u3002\n        System.out.println(maps.containsValue(100));  \/\/\n        System.out.println(maps.containsValue(10));  \/\/\n        System.out.println(maps.containsValue(22)); \/\/\n\n        \/\/ {huawei=100, \u624b\u8868=10, \u751f\u6d3b\u7528\u54c1=10, \u5a03\u5a03=20}\n        \/\/ 8.\u83b7\u53d6\u5168\u90e8\u952e\u7684\u96c6\u5408\uff1apublic Set<K> keySet()\n        Set<String> keys = maps.keySet();\n        System.out.println(keys);\n\n        System.out.println(\"------------------------------\");\n        \/\/ 9.\u83b7\u53d6\u5168\u90e8\u503c\u7684\u96c6\u5408\uff1aCollection<V> values();\n        Collection<Integer> values = maps.values();\n        System.out.println(values);\n\n        \/\/ 10.\u96c6\u5408\u7684\u5927\u5c0f\n        System.out.println(maps.size()); \/\/ 4\n\n        \/\/ 11.\u5408\u5e76\u5176\u4ed6Map\u96c6\u5408\u3002(\u62d3\u5c55)\n        Map<String , Integer> map1 = new HashMap<>();\n        map1.put(\"java1\", 1);\n        map1.put(\"java2\", 100);\n        Map<String , Integer> map2 = new HashMap<>();\n        map2.put(\"java2\", 1);\n        map2.put(\"java3\", 100);\n        map1.putAll(map2); \/\/ \u628a\u96c6\u5408map2\u7684\u5143\u7d20\u62f7\u8d1d\u4e00\u4efd\u5230map1\u4e2d\u53bb\n        System.out.println(map1);\n        System.out.println(map2);\n    }\n}<\/code><\/pre>\n\n\n\n
Map\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u6709\uff1a3\u79cd
\u65b9\u5f0f\u4e00\uff1a\u952e\u627e\u503c\u7684\u65b9\u5f0f\u904d\u5386\uff1a\u5148\u83b7\u53d6Map\u96c6\u5408\u5168\u90e8\u7684\u952e\uff0c\u518d\u6839\u636e\u904d\u5386\u952e\u627e\u503c
\u65b9\u5f0f\u4e8c\uff1a\u952e\u503c\u5bf9\u7684\u65b9\u5f0f\u904d\u5386\uff0c\u628a\u201c\u952e\u503c\u5bf9\u201c\u770b\u6210\u4e00\u4e2a\u6574\u4f53\uff0c\u96be\u5ea6\u8f83\u5927
\u65b9\u5f0f\u4e09\uff1aJDK 1.8\u5f00\u59cb\u4e4b\u540e\u7684\u65b0\u6280\u672f\uff1aLambda\u8868\u8fbe\u5f0f<\/p>\n\n\n\n
\/*-----------------------\u904d\u5386\u65b9\u5f0f1-------------------------*\/\nimport java.util.HashMap;\nimport java.util.Map;\nimport java.util.Set;\n\n\/**\n    \u76ee\u6807\uff1aMap\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u4e00\uff1a\u952e\u627e\u503c\n\n    Map\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u6709\uff1a3\u79cd\u3002\n        \uff081\uff09\u201c\u952e\u627e\u503c\u201d\u7684\u65b9\u5f0f\u904d\u5386\uff1a\u5148\u83b7\u53d6Map\u96c6\u5408\u5168\u90e8\u7684\u952e\uff0c\u518d\u6839\u636e\u904d\u5386\u952e\u627e\u503c\u3002\n        \uff082\uff09\u201c\u952e\u503c\u5bf9\u201d\u7684\u65b9\u5f0f\u904d\u5386\uff1a\u96be\u5ea6\u8f83\u5927\u3002\n        \uff083\uff09JDK 1.8\u5f00\u59cb\u4e4b\u540e\u7684\u65b0\u6280\u672f\uff1aLambda\u8868\u8fbe\u5f0f\u3002\uff08\u6682\u65f6\u4e86\u89e3\uff09\n\n    a.\u201c\u952e\u627e\u503c\u201d\u7684\u65b9\u5f0f\u904d\u5386Map\u96c6\u5408\u3002\n        1.\u5148\u83b7\u53d6Map\u96c6\u5408\u7684\u5168\u90e8\u952e\u7684Set\u96c6\u5408\u3002\n        2.\u904d\u5386\u952e\u7684Set\u96c6\u5408\uff0c\u7136\u540e\u901a\u8fc7\u952e\u627e\u503c\u3002\n    \u5c0f\u7ed3\uff1a\n        \u4ee3\u7801\u7b80\u5355\uff0c\u9700\u8981\u8bb0\u4f4f!\n\n *\/\npublic class MapDemo01 {\n    public static void main(String[] args) {\n        Map<String , Integer> maps = new HashMap<>();\n        \/\/ 1.\u6dfb\u52a0\u5143\u7d20: \u65e0\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u3002\n        maps.put(\"\u5a03\u5a03\",30);\n        maps.put(\"iphoneX\",100);\n        maps.put(\"huawei\",1000);\n        maps.put(\"\u751f\u6d3b\u7528\u54c1\",10);\n        maps.put(\"\u624b\u8868\",10);\n        System.out.println(maps);\n        \/\/ maps = {huawei=1000, \u624b\u8868=10, \u751f\u6d3b\u7528\u54c1=10, iphoneX=100, \u5a03\u5a03=30}\n\n        \/\/ 1\u3001\u952e\u627e\u503c\uff1a\u7b2c\u4e00\u6b65\uff1a\u5148\u62ff\u5230\u96c6\u5408\u7684\u5168\u90e8\u952e\u3002\n        Set<String> keys = maps.keySet();\n        \/\/ 2\u3001\u7b2c\u4e8c\u6b65\uff1a\u904d\u5386\u6bcf\u4e2a\u952e\uff0c\u6839\u636e\u952e\u63d0\u53d6\u503c\n        for (String key : keys) {\n            int value = maps.get(key);\n            System.out.println(key + \"===>\" + value);\n        }\n\n    }\n}\n\/*-----------------------\u904d\u5386\u65b9\u5f0f2-------------------------*\/\nimport java.util.HashMap;\nimport java.util.Map;\nimport java.util.Set;\n\n\/**\n    \u76ee\u6807\uff1aMap\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u3002\n\n    Map\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u6709\uff1a3\u79cd\u3002\n        \uff081\uff09\u201c\u952e\u627e\u503c\u201d\u7684\u65b9\u5f0f\u904d\u5386\uff1a\u5148\u83b7\u53d6Map\u96c6\u5408\u5168\u90e8\u7684\u952e\uff0c\u518d\u6839\u636e\u952e\u627e\u503c\u3002\n        \uff082\uff09\u201c\u952e\u503c\u5bf9\u201d\u7684\u65b9\u5f0f\u904d\u5386\uff1a\u96be\u5ea6\u8f83\u5927\u3002\n        \uff083\uff09JDK 1.8\u5f00\u59cb\u4e4b\u540e\u7684\u65b0\u6280\u672f\uff1aLambda\u8868\u8fbe\u5f0f\u3002\n\n    b.\u201c\u952e\u503c\u5bf9\u201d\u7684\u65b9\u5f0f\u904d\u5386\uff1a\n        1.\u628aMap\u96c6\u5408\u8f6c\u6362\u6210\u4e00\u4e2aSet\u96c6\u5408:Set<Map.Entry<K, V>> entrySet();\n        2.\u6b64\u65f6\u952e\u503c\u5bf9\u5143\u7d20\u7684\u7c7b\u578b\u5c31\u786e\u5b9a\u4e86\uff0c\u7c7b\u578b\u662f\u952e\u503c\u5bf9\u5b9e\u4f53\u7c7b\u578b\uff1aMap.Entry<K, V>\n        3.\u63a5\u4e0b\u6765\u5c31\u53ef\u4ee5\u7528foreach\u904d\u5386\u8fd9\u4e2aSet\u96c6\u5408\uff0c\u7c7b\u578b\u7528Map.Entry<K, V>\n *\/\npublic class MapDemo02 {\n    public static void main(String[] args) {\n        Map<String , Integer> maps = new HashMap<>();\n        \/\/ 1.\u6dfb\u52a0\u5143\u7d20: \u65e0\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u3002\n        maps.put(\"\u5a03\u5a03\",30);\n        maps.put(\"iphoneX\",100);\n        maps.put(\"huawei\",1000);\n        maps.put(\"\u751f\u6d3b\u7528\u54c1\",10);\n        maps.put(\"\u624b\u8868\",10);\n        System.out.println(maps);\n        \/\/ maps = {huawei=1000, \u624b\u8868=10, \u751f\u6d3b\u7528\u54c1=10, iphoneX=100, \u5a03\u5a03=30}\n        \/**\n            maps = {huawei=1000, \u624b\u8868=10, \u751f\u6d3b\u7528\u54c1=10, iphoneX=100, \u5a03\u5a03=30}\n                \ud83d\udc47\n            \u4f7f\u7528foreach\u904d\u5386map\u96c6\u5408.\u53d1\u73b0Map\u96c6\u5408\u7684\u952e\u503c\u5bf9\u5143\u7d20\u76f4\u63a5\u662f\u6ca1\u6709\u7c7b\u578b\u7684\u3002\u6240\u4ee5\u4e0d\u53ef\u4ee5\u76f4\u63a5foreach\u904d\u5386\u96c6\u5408\u3002\n                \ud83d\udc47\n            \u53ef\u4ee5\u901a\u8fc7\u8c03\u7528Map\u7684\u65b9\u6cd5 entrySet\u628aMap\u96c6\u5408\u8f6c\u6362\u6210Set\u96c6\u5408\u5f62\u5f0f  maps.entrySet();\n                \ud83d\udc47\n            Set<Map.Entry<String,Integer>> entries =  maps.entrySet();\n             [(huawei=1000), (\u624b\u8868=10), (\u751f\u6d3b\u7528\u54c1=10), (iphoneX=100), (\u5a03\u5a03=30)]\n                              entry\n                \ud83d\udc47\n            \u6b64\u65f6\u53ef\u4ee5\u4f7f\u7528foreach\u904d\u5386\n       *\/\n       \/\/ 1\u3001\u628aMap\u96c6\u5408\u8f6c\u6362\u6210Set\u96c6\u5408\n        Set<Map.Entry<String, Integer>> entries = maps.entrySet();\n        \/\/ 2\u3001\u5f00\u59cb\u904d\u5386\n        for(Map.Entry<String, Integer> entry : entries){\n            String key = entry.getKey();\n            int value = entry.getValue();\n            System.out.println(key + \"====>\" + value);\n        }\n    }\n}\n\/*-----------------------\u904d\u5386\u65b9\u5f0f3-------------------------*\/\nimport java.util.HashMap;\nimport java.util.Map;\nimport java.util.function.BiConsumer;\n\n\/**\n    \u76ee\u6807\uff1aMap\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u3002\n\n    Map\u96c6\u5408\u7684\u904d\u5386\u65b9\u5f0f\u6709\uff1a3\u79cd\u3002\n        \uff081\uff09\u201c\u952e\u627e\u503c\u201d\u7684\u65b9\u5f0f\u904d\u5386\uff1a\u5148\u83b7\u53d6Map\u96c6\u5408\u5168\u90e8\u7684\u952e\uff0c\u518d\u6839\u636e\u952e\u627e\u503c\u3002\n        \uff082\uff09\u201c\u952e\u503c\u5bf9\u201d\u7684\u65b9\u5f0f\u904d\u5386\uff1a\u96be\u5ea6\u8f83\u5927\u3002\n        \uff083\uff09JDK 1.8\u5f00\u59cb\u4e4b\u540e\u7684\u65b0\u6280\u672f\uff1aLambda\u8868\u8fbe\u5f0f\u3002\n\n    c.JDK 1.8\u5f00\u59cb\u4e4b\u540e\u7684\u65b0\u6280\u672f\uff1aLambda\u8868\u8fbe\u5f0f\u3002\uff08\u6682\u65f6\u4e86\u89e3\uff09\n *\/\npublic class MapDemo03 {\n    public static void main(String[] args) {\n        Map<String , Integer> maps = new HashMap<>();\n        \/\/ 1.\u6dfb\u52a0\u5143\u7d20: \u65e0\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u3002\n        maps.put(\"\u5a03\u5a03\",30);\n        maps.put(\"iphoneX\",100);\/\/  Map\u96c6\u5408\u540e\u9762\u91cd\u590d\u7684\u952e\u5bf9\u5e94\u7684\u5143\u7d20\u4f1a\u8986\u76d6\u524d\u9762\u91cd\u590d\u7684\u6574\u4e2a\u5143\u7d20\uff01\n        maps.put(\"huawei\",1000);\n        maps.put(\"\u751f\u6d3b\u7528\u54c1\",10);\n        maps.put(\"\u624b\u8868\",10);\n        System.out.println(maps);\n\n        \/\/  maps = {huawei=1000, \u624b\u8868=10, \u751f\u6d3b\u7528\u54c1=10, iphoneX=100, \u5a03\u5a03=30}\n\n\/\/        maps.forEach(new BiConsumer<String, Integer>() {\n\/\/            @Override\n\/\/            public void accept(String key, Integer value) {\n\/\/                System.out.println(key + \"--->\" + value);\n\/\/            }\n\/\/        });\n\n        maps.forEach((k, v) -> {\n                System.out.println(k + \"--->\" + v);\n        });\n\n    }\n}<\/code><\/pre>\n\n\n\n
Example\uff1aMap\u96c6\u5408\u6848\u4f8b-\u7edf\u8ba1\u6295\u7968\u4eba\u6570
\u9700\u6c42
\u67d0\u4e2a\u73ed\u7ea780\u540d\u5b66\u751f\uff0c\u73b0\u5728\u9700\u8981\u7ec4\u6210\u79cb\u6e38\u6d3b\u52a8\uff0c\u73ed\u957f\u63d0\u4f9b\u4e86\u56db\u4e2a\u666f\u70b9\u4f9d\u6b21\u662f\uff08A\u3001B\u3001C\u3001D\uff09,\u6bcf\u4e2a\u5b66\u751f\u53ea\u80fd\u9009\u62e9\u4e00\u4e2a\u666f\u70b9\uff0c\u8bf7\u7edf\u8ba1\u51fa\u6700\u7ec8\u54ea\u4e2a\u666f\u70b9\u60f3\u53bb\u7684\u4eba\u6570\u6700\u591a\u3002
\u5206\u6790
\u5c0680\u4e2a\u5b66\u751f\u9009\u62e9\u7684\u6570\u636e\u62ff\u5230\u7a0b\u5e8f\u4e2d\u53bb\u3002
\u5b9a\u4e49Map\u96c6\u5408\u7528\u4e8e\u5b58\u50a8\u6700\u7ec8\u7edf\u8ba1\u7684\u7ed3\u679c\u3002
\u904d\u538680\u4e2a\u5b66\u751f\u9009\u62e9\u7684\u6570\u636e\uff0c\u770bMap\u96c6\u5408\u4e2d\u662f\u5426\u5b58\u5728\uff0c\u4e0d\u5b58\u5728\u5b58\u5165\u201c\u6570\u636e=1\u201c\uff0c\u5b58\u5728\u5219\u5176\u5bf9\u5e94\u503c+1<\/p>\n\n\n\n
\/**\n   \u9700\u6c42\uff1a\u7edf\u8ba1\u6295\u7968\u4eba\u6570\n *\/\npublic class MapTest1 {\n    public static void main(String[] args) {\n         \/\/ 1\u3001\u628a80\u4e2a\u5b66\u751f\u9009\u62e9\u7684\u6570\u636e\u62ff\u8fdb\u6765\u3002\n        String[] selects = {\"A\" , \"B\", \"C\", \"D\"};\n        StringBuilder sb = new StringBuilder();\n        Random r = new Random();\n        for (int i = 0; i < 80; i++) {\n            sb.append(selects[r.nextInt(selects.length)]);\n        }\n        System.out.println(sb);\n\n        \/\/ 2\u3001\u5b9a\u4e49\u4e00\u4e2aMap\u96c6\u5408\u8bb0\u5f55\u6700\u7ec8\u7edf\u8ba1\u7684\u7ed3\u679c\uff1a A=30 B=20 C=20 D=10  \u952e\u662f\u666f\u70b9 \u503c\u662f\u9009\u62e9\u7684\u6570\u91cf\n        Map<Character, Integer> infos = new HashMap<>(); \/\/\n\n        \/\/ 3\u3001\u904d\u538680\u4e2a\u5b66\u751f\u9009\u62e9\u7684\u6570\u636e\n        for (int i = 0; i < sb.length(); i++) {\n            \/\/ 4\u3001\u63d0\u53d6\u5f53\u524d\u9009\u62e9\u666f\u70b9\u5b57\u7b26\n            char ch = sb.charAt(i);\n            \/\/ 5\u3001\u5224\u65adMap\u96c6\u5408\u4e2d\u662f\u5426\u5b58\u5728\u8fd9\u4e2a\u952e\n            if(infos.containsKey(ch)){\n                 \/\/ \u8ba9\u5176\u503c + 1\n                infos.put(ch , infos.get(ch) + 1);\n            }else {\n                \/\/ \u8bf4\u660e\u6b64\u666f\u70b9\u662f\u7b2c\u4e00\u6b21\u88ab\u9009\n                infos.put(ch , 1);\n            }\n        }\n\n        \/\/ 4\u3001\u8f93\u51fa\u96c6\u5408\n        System.out.println(infos);\n\n    }\n}<\/code><\/pre>\n\n\n\n
\"\"<\/figure>\n\n\n\n
HashMap\u7684\u7279\u70b9
HashMap\u662fMap\u91cc\u9762\u7684\u4e00\u4e2a\u5b9e\u73b0\u7c7b\u3002\u7279\u70b9\u90fd\u662f\u7531\u952e\u51b3\u5b9a\u7684\uff1a\u65e0\u5e8f\u3001\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15
\u6ca1\u6709\u989d\u5916\u9700\u8981\u5b66\u4e60\u7684\u7279\u6709\u65b9\u6cd5\uff0c\u76f4\u63a5\u4f7f\u7528Map\u91cc\u9762\u7684\u65b9\u6cd5\u5c31\u53ef\u4ee5\u4e86\u3002
HashMap\u8ddfHashSet\u5e95\u5c42\u539f\u7406\u662f\u4e00\u6a21\u4e00\u6837\u7684\uff0c\u90fd\u662f\u54c8\u5e0c\u8868\u7ed3\u6784\uff0c\u53ea\u662fHashMap\u7684\u6bcf\u4e2a\u5143\u7d20\u5305\u542b\u4e24\u4e2a\u503c\u800c\u5df2
\u5b9e\u9645\u4e0a\uff1aSet\u7cfb\u5217\u96c6\u5408\u7684\u5e95\u5c42\u5c31\u662fMap\u5b9e\u73b0\u7684\uff0c\u53ea\u662fSet\u96c6\u5408\u4e2d\u7684\u5143\u7d20\u53ea\u8981\u952e\u6570\u636e\uff0c\u4e0d\u8981\u503c\u6570\u636e\u800c\u5df2
\u4f9d\u8d56hashCode\u65b9\u6cd5\u548cequals\u65b9\u6cd5\u4fdd\u8bc1\u952e\u7684\u552f\u4e00
\u5982\u679c\u952e\u8981\u5b58\u50a8\u7684\u662f\u81ea\u5b9a\u4e49\u5bf9\u8c61\uff0c\u9700\u8981\u91cd\u5199hashCode\u548cequals\u65b9\u6cd5\u3002<\/p>\n\n\n\n
LinkedHashMap\u96c6\u5408\u6982\u8ff0\u548c\u7279\u70b9
\u7531\u952e\u51b3\u5b9a\uff1a\u6709\u5e8f\u3001\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\u3002
\u8fd9\u91cc\u7684\u6709\u5e8f\u6307\u7684\u662f\u4fdd\u8bc1\u5b58\u50a8\u548c\u53d6\u51fa\u7684\u5143\u7d20\u987a\u5e8f\u4e00\u81f4
\u539f\u7406\uff1a\u5e95\u5c42\u6570\u636e\u7ed3\u6784\u662f\u4f9d\u7136\u54c8\u5e0c\u8868\uff0c\u53ea\u662f\u6bcf\u4e2a\u952e\u503c\u5bf9\u5143\u7d20\u53c8\u989d\u5916\u7684\u591a\u4e86\u4e00\u4e2a\u53cc\u94fe\u8868\u7684\u673a\u5236\u8bb0\u5f55\u5b58\u50a8\u7684\u987a\u5e8f<\/p>\n\n\n\n
\/**\n    \u76ee\u6807\uff1a\u8ba4\u8bc6Map\u4f53\u7cfb\u7684\u7279\u70b9\uff1a\u6309\u7167\u952e\u65e0\u5e8f\uff0c\u4e0d\u91cd\u590d\uff0c\u65e0\u7d22\u5f15\u3002\u503c\u4e0d\u505a\u8981\u6c42\u3002\n *\/\npublic class LinkedHashMapDemo2 {\n    public static void main(String[] args) {\n        \/\/ 1\u3001\u521b\u5efa\u4e00\u4e2aMap\u96c6\u5408\u5bf9\u8c61\n        Map<String, Integer> maps = new LinkedHashMap<>();\n        maps.put(\"\u9e3f\u661f\u5c14\u514b\", 3);\n        maps.put(\"Java\", 1);\n        maps.put(\"\u67b8\u675e\", 100);\n        maps.put(\"Java\", 100); \/\/ \u8986\u76d6\u524d\u9762\u7684\u6570\u636e\n        maps.put(null, null);\n        System.out.println(maps);\n\n    }\n}\n\/*-------\u8f93\u51fa-------------*\/\n{\u9e3f\u661f\u5c14\u514b=3, Java=100, \u67b8\u675e=100, null=null}<\/code><\/pre>\n\n\n\n
TreeMap\u96c6\u5408\u6982\u8ff0\u548c\u7279\u70b9\uff1a
\u7531\u952e\u51b3\u5b9a\u7279\u6027\uff1a\u4e0d\u91cd\u590d\u3001\u65e0\u7d22\u5f15\u3001\u53ef\u6392\u5e8f
\u53ef\u6392\u5e8f\uff1a\u6309\u7167\u952e\u6570\u636e\u7684\u5927\u5c0f\u9ed8\u8ba4\u5347\u5e8f\uff08\u6709\u5c0f\u5230\u5927\uff09\u6392\u5e8f\u3002\u53ea\u80fd\u5bf9\u952e\u6392\u5e8f\u3002
\u6ce8\u610f\uff1aTreeMap\u96c6\u5408\u662f\u4e00\u5b9a\u8981\u6392\u5e8f\u7684\uff0c\u53ef\u4ee5\u9ed8\u8ba4\u6392\u5e8f\uff0c\u4e5f\u53ef\u4ee5\u5c06\u952e\u6309\u7167\u6307\u5b9a\u7684\u89c4\u5219\u8fdb\u884c\u6392\u5e8f
TreeMap\u8ddfTreeSet\u4e00\u6837\u5e95\u5c42\u539f\u7406\u662f\u4e00\u6837\u7684
TreeMap\u96c6\u5408\u81ea\u5b9a\u4e49\u6392\u5e8f\u89c4\u5219\u67092\u79cd\uff1a
\u7c7b\u5b9e\u73b0Comparable\u63a5\u53e3\uff0c\u91cd\u5199\u6bd4\u8f83\u89c4\u5219
\u96c6\u5408\u81ea\u5b9a\u4e49Comparator\u6bd4\u8f83\u5668\u5bf9\u8c61\uff0c\u91cd\u5199\u6bd4\u8f83\u89c4\u5219<\/p>\n\n\n\n
import com.itheima.d1_collection_set.Student;\nimport java.util.HashMap;\nimport java.util.Map;\n\npublic class HashMapDemo1 {\n    public static void main(String[] args) {\n         \/\/ Map\u96c6\u5408\u662f\u6839\u636e\u952e\u53bb\u9664\u91cd\u590d\u5143\u7d20\n        Map<Student, String> maps = new HashMap<>();\n\n        Student s1 = new Student(\"\u65e0\u6059\", 20, '\u7537');\n        Student s2 = new Student(\"\u65e0\u6059\", 20, '\u7537');\n        Student s3 = new Student(\"\u5468\u96c4\", 21, '\u7537');\n\n        maps.put(s1, \"\u5317\u4eac\");\n        maps.put(s2, \"\u4e0a\u6d77\");\n        maps.put(s3, \"\u5e7f\u5dde\");\n\n        System.out.println(maps);\n    }\n}\n\/*------------\u8f93\u51fa-------------*\/\n{Student{name='\u65e0\u6059', age=20, sex=\u7537}=\u4e0a\u6d77, Student{name='\u5468\u96c4', age=21, sex=\u7537}=\u5e7f\u5dde}<\/code><\/pre>\n\n\n\n
\u96c6\u5408\u5d4c\u5957<\/p>\n\n\n\n
Map\u96c6\u5408\u6848\u4f8b-\u7edf\u8ba1\u6295\u7968\u4eba\u6570(\u96c6\u5408\u7684\u5d4c\u5957)
\u9700\u6c42\uff1a
\u67d0\u4e2a\u73ed\u7ea7\u591a\u540d\u5b66\u751f\uff0c\u73b0\u5728\u9700\u8981\u7ec4\u6210\u79cb\u6e38\u6d3b\u52a8\uff0c\u73ed\u957f\u63d0\u4f9b\u4e86\u56db\u4e2a\u666f\u70b9\u4f9d\u6b21\u662f\uff08A\u3001B\u3001C\u3001D\uff09,\u6bcf\u4e2a\u5b66\u751f\u53ef\u4ee5\u9009\u62e9\u591a\u4e2a\u666f\u70b9\uff0c\u8bf7\u7edf\u8ba1\u51fa\u6700\u7ec8\u54ea\u4e2a\u666f\u70b9\u60f3\u53bb\u7684\u4eba\u6570\u6700\u591a\u3002
\u5206\u6790\uff1a
\u5c0680\u4e2a\u5b66\u751f\u9009\u62e9\u7684\u6570\u636e\u62ff\u5230\u7a0b\u5e8f\u4e2d\u53bb\uff0c\u9700\u8981\u8bb0\u4f4f\u6bcf\u4e2a\u5b66\u751f\u9009\u62e9\u7684\u60c5\u51b5\u3002
\u5b9a\u4e49Map\u96c6\u5408\u7528\u4e8e\u5b58\u50a8\u6700\u7ec8\u7edf\u8ba1\u7684\u7ed3\u679c\u3002<\/p>\n\n\n\n
import java.util.*;\n\n\/**\n   \u9700\u6c42\uff1a\u7edf\u8ba1\u6295\u7968\u4eba\u6570\n *\/\npublic class MapTest4 {\n    public static void main(String[] args) {\n        \/\/ 1\u3001\u8981\u6c42\u7a0b\u5e8f\u8bb0\u5f55\u6bcf\u4e2a\u5b66\u751f\u9009\u62e9\u7684\u60c5\u51b5\u3002\n        \/\/ \u4f7f\u7528\u4e00\u4e2aMap\u96c6\u5408\u5b58\u50a8\u3002\n        Map<String, List<String>> data = new HashMap<>();\n\n        \/\/ 2\u3001\u628a\u5b66\u751f\u9009\u62e9\u7684\u6570\u636e\u5b58\u5165\u8fdb\u53bb\u3002\n        List<String> selects = new ArrayList<>();\n        Collections.addAll(selects, \"A\", \"C\");\n        data.put(\"\u7f57\u52c7\", selects);\n\n        List<String> selects1 = new ArrayList<>();\n        Collections.addAll(selects1, \"B\", \"C\" , \"D\");\n        data.put(\"\u80e1\u6d9b\", selects1);\n\n        List<String> selects2 = new ArrayList<>();\n        Collections.addAll(selects2 , \"A\",  \"B\", \"C\" , \"D\");\n        data.put(\"\u5218\u519b\", selects2);\n\n        System.out.println(data);\n\n        \/\/ 3\u3001\u7edf\u8ba1\u6bcf\u4e2a\u666f\u70b9\u9009\u62e9\u7684\u4eba\u6570\u3002\n        Map<String, Integer> infos = new HashMap<>(); \/\/ {}\n\n        \/\/ 4\u3001\u63d0\u53d6\u6240\u6709\u4eba\u9009\u62e9\u7684\u666f\u70b9\u7684\u4fe1\u606f\u3002\n        Collection<List<String>> values = data.values();\n        System.out.println(values);\n        \/\/ values = [[A, B, C, D], [B, C, D], [A, C]]\n        \/\/             value\n\n        for (List<String> value : values) {\n            for (String s : value) {\n                \/\/ \u6709\u6ca1\u6709\u5305\u542b\u8fd9\u4e2a\u666f\u70b9\n                if(infos.containsKey(s)){\n                    infos.put(s, infos.get(s) + 1);\n                }else {\n                    infos.put(s , 1);\n                }\n            }\n        }\n\n        System.out.println(infos);\n    }\n}<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
\u96c6\u5408\uff0c\u6cdb\u578b\uff0cMap<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[23],"tags":[],"class_list":["post-628","post","type-post","status-publish","format-standard","hentry","category-java"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/posts\/628","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/comments?post=628"}],"version-history":[{"count":16,"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/posts\/628\/revisions"}],"predecessor-version":[{"id":1444,"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/posts\/628\/revisions\/1444"}],"wp:attachment":[{"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/media?parent=628"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/categories?post=628"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/tags?post=628"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}