{"id":548,"date":"2022-11-16T11:30:48","date_gmt":"2022-11-16T11:30:48","guid":{"rendered":"http:\/\/www.gislxz.com\/?p=548"},"modified":"2022-11-21T05:31:52","modified_gmt":"2022-11-21T05:31:52","slug":"jdbc","status":"publish","type":"post","link":"https:\/\/www.gislxz.com\/index.php\/2022\/11\/16\/jdbc\/","title":{"rendered":"JDBC\u5b66\u4e60\u7b14\u8bb0"},"content":{"rendered":"\n

\u7ed5\u6765\u7ed5\u53bb\u8fd8\u662f\u6765\u5b66Java\u4e86\uff0c\u8ddf\u7740\u7f51\u8bfe\u5feb\u901f\u8fc7\u4e86\u4e00\u904djava\u57fa\u7840\u548c\u6570\u636e\u5e93\u57fa\u7840\uff0c\u7528\u5230\u5565\u518d\u56de\u53bb\u770b\u5427\uff0c\u5148\u76f4\u63a5\u4e0a\u624bJDBC\u3002<\/p>\n\n\n\n

01-JDBC\u7b80\u4ecb \u5feb\u901f\u5165\u95e8_\u54d4\u54e9\u54d4\u54e9_bilibili<\/a><\/p>\n\n\n\n

JDBC\u7f16\u7a0b - \u5ed6\u96ea\u5cf0\u7684\u5b98\u65b9\u7f51\u7ad9 (liaoxuefeng.com)<\/a><\/p>\n\n\n\n

\u6559\u7a0b\u662f\u4ee5mysql\u4e3a\u4f8b\uff0c\u6211\u5c31\u76f4\u63a5\u7528postgreSql\u4e86\uff0c\u53cd\u6b63\u53ea\u662f\u9a71\u52a8\u4e0d\u4e00\u6837\u3002<\/p>\n\n\n\n

\u65b0\u5efajava\u5de5\u7a0b\uff0c\u5728src\u91cc\u65b0\u5efa\u7c7b\uff0c\u76f4\u63a5\u5728\u4e3b\u51fd\u6570\u91cc\u5199\u4e2asql\u6267\u884c\u65b9\u6cd5\u3002<\/p>\n\n\n\n

\u9996\u5148\u8981\u88c5\u4e2a\u9a71\u52a8Download | pgJDBC (postgresql.org)<\/a><\/p>\n\n\n\n

\"\"
\u5728\u9879\u76ee\u7ed3\u6784\u91cc\u5bfc\u5165\u5e93<\/figcaption><\/figure>\n\n\n\n
import java.sql.Connection;\nimport java.sql.DriverManager;\nimport java.sql.Statement;\n\npublic class jdbcDemo {\n    public static void main(String[] args) throws Exception{\n        \/\/1.\u6ce8\u518c\u9a71\u52a8\n        Class.forName(\"org.postgresql.Driver\");\n\n        \/\/2.\u83b7\u53d6\u94fe\u63a5\n        String url = \"jdbc:postgresql:\/\/localhost:5432\/Test0\";\n        String username = \"postgres\";\n        String password = \"***\";\n        Connection conn = DriverManager.getConnection(url,username,password);\n\n        \/\/3.\u5b9a\u4e8eSQL\u8bed\u53e5\n        String sql = \"Insert into test values(3,'xiaowang');\";\n\n        \/\/4.\u83b7\u53d6\u6267\u884csql\u7684\u5bf9\u8c61statement\n        Statement stmt = conn.createStatement();\n\n        \/\/5.\u6267\u884csql\n        int count = stmt.executeUpdate(sql);\/\/\u8fd4\u56de\u53d7\u5f71\u54cd\u7684\u884c\u6570\n\n        System.out.println(count);\n\n        stmt.close();\n        conn.close();\n    }\n}\n<\/code><\/pre>\n\n\n\n
\"\"
\u6210\u529f\u6dfb\u52a0\u4e86\u4e00\u884c\u8bb0\u5f55<\/figcaption><\/figure>\n\n\n\n
JDBC\u4e3b\u8981\u6709\u4ee5\u4e0b\u51e0\u4e2aAPI<\/p>\n\n\n\n
1 DriverManager<\/p>\n\n\n\n
\u6ce8\u518c\u9a71\u52a8\uff0c\u83b7\u53d6connection\u8fde\u63a5\u5bf9\u8c61\uff0c\u6ca1\u5565\u8bf4\u7684<\/p>\n\n\n\n
2 Connection<\/p>\n\n\n\n
2.1\u6267\u884cSQL\u5bf9\u8c61<\/p>\n\n\n\n
\u666e\u901a\u6267\u884cSQL<\/p>\n\n\n\n
\u9884\u7f16\u8bd1SQL\uff0c\u9632\u6b62\u6ce8\u5165<\/p>\n\n\n\n
\u6267\u884c\u5b58\u50a8\u8fc7\u7a0b\u7684\u5bf9\u8c61<\/p>\n\n\n\n
2.2\u4e8b\u52a1\u7ba1\u7406<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
public class JDBCDemo3_connection {\n    public static void main(String[] args) throws Exception{\n        \/\/1.\u6ce8\u518c\u9a71\u52a8\n        Class.forName(\"org.postgresql.Driver\");\n\n        \/\/2.\u83b7\u53d6\u94fe\u63a5\n        String url = \"jdbc:postgresql:\/\/localhost:5432\/Test0\";\n        String username = \"postgres\";\n        String password = \"\u00b7\";\n        Connection conn = DriverManager.getConnection(url,username,password);\n\n        \/\/3.\u5b9a\u4e8eSQL\u8bed\u53e5\n        String sql1 = \"Insert into test values(3,'xiaowang');\";\n        String sql2 = \"Insert into test values(4,'xiaoming');\";\n        \/\/4.\u83b7\u53d6\u6267\u884csql\u7684\u5bf9\u8c61statement\n        Statement stmt = conn.createStatement();\n\n        try {\n            \/\/ \u5f00\u542f\u4e8b\u52a1\n            conn.setAutoCommit(false);\n            \/\/5.\u6267\u884csql\n            int count1 = stmt.executeUpdate(sql1);\/\/\u8fd4\u56de\u53d7\u5f71\u54cd\u7684\u884c\u6570\n            System.out.println(count1);\n            int count2 = stmt.executeUpdate(sql2);\/\/\u8fd4\u56de\u53d7\u5f71\u54cd\u7684\u884c\u6570\n            System.out.println(count2);\n\n            \/\/\u63d0\u4ea4\u4e8b\u52a1\n            conn.commit();\n        } catch (Exception throwables) {\n            conn.rollback();\n            throwables.printStackTrace();\n        }\n\n        stmt.close();\n        conn.close();\n    }\n}\n\n\/\/\u6a21\u677f\nConnection conn = openConnection();\ntry {\n    \/\/ \u5173\u95ed\u81ea\u52a8\u63d0\u4ea4:\n    conn.setAutoCommit(false);\n    \/\/ \u6267\u884c\u591a\u6761SQL\u8bed\u53e5:\n    insert(); update(); delete();\n    \/\/ \u63d0\u4ea4\u4e8b\u52a1:\n    conn.commit();\n} catch (SQLException e) {\n    \/\/ \u56de\u6eda\u4e8b\u52a1:\n    conn.rollback();\n} finally {\n    conn.setAutoCommit(true);\n    conn.close();\n}<\/code><\/pre>\n\n\n\n
3 Statement<\/p>\n\n\n\n
3.1 int executeUpdate(sql); \u6267\u884cDML\uff0cDDL\u8bed\u53e5<\/p>\n\n\n\n
public class JDBCDemo4_Statement {\n    \/\/\u6267\u884cDML\u8bed\u53e5\n    @Test\n    public void testDML() throws Exception{\n        \/\/1.\u6ce8\u518c\u9a71\u52a8\n        Class.forName(\"org.postgresql.Driver\");\n\n        \/\/2.\u83b7\u53d6\u94fe\u63a5\n        String url = \"jdbc:postgresql:\/\/localhost:5432\/Test0\";\n        String username = \"postgres\";\n        String password = \"Lxz325625\";\n        Connection conn = DriverManager.getConnection(url,username,password);\n\n        \/\/3.\u5b9a\u4e8eSQL\u8bed\u53e5\n        String sql = \"update test set debt=50 where name='xiaowang'\";\n\n        \/\/4.\u83b7\u53d6\u6267\u884csql\u7684\u5bf9\u8c61statement\n        Statement stmt = conn.createStatement();\n\n        \/\/5.\u6267\u884csql\n        int count = stmt.executeUpdate(sql);\/\/\u6267\u884c\u5b8cDML\u51fd\u6570\u8fd4\u56de\u53d7\u5f71\u54cd\u7684\u884c\u6570\n\n        \/\/System.out.println(count);\n        if(count>0){\n            System.out.println(\"\u4fee\u6539\u6210\u529f\");\n        }else{\n            System.out.println(\"\u4fee\u6539\u5931\u8d25\");\n        }\n\n        stmt.close();\n        conn.close();\n    }\n<\/code><\/pre>\n\n\n\n
3.2 ResultSet executeQuery(sql); \u6267\u884cDQL\u8bed\u53e5<\/p>\n\n\n\n
4 ResultSet<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
@Test\n    public void testDML() throws Exception{\n        \/\/1.\u6ce8\u518c\u9a71\u52a8\n        Class.forName(\"org.postgresql.Driver\");\n\n        \/\/2.\u83b7\u53d6\u94fe\u63a5\n        String url = \"jdbc:postgresql:\/\/localhost:5432\/Test0\";\n        String username = \"postgres\";\n        String password = \"Lxz325625\";\n        Connection conn = DriverManager.getConnection(url,username,password);\n\n        \/\/3.\u5b9a\u4e8eSQL\u8bed\u53e5\n        String sql = \"Select * from test\";\n\n        \/\/4.\u83b7\u53d6\u6267\u884csql\u7684\u5bf9\u8c61statement\n        Statement stmt = conn.createStatement();\n\n        \/\/5.\u6267\u884csql\n        try(ResultSet rs = stmt.executeQuery(sql)){\n            while(rs.next()){\n                int debt = rs.getInt(1);\/\/\u5217\u53f7\u6216\u8005\u5217\u540d\n                String name = rs.getString(2);\n                System.out.println(debt);\n                System.out.println(name);\n            }\n        }\n\n        stmt.close();\n        conn.close();\n    }<\/code><\/pre>\n\n\n\n
ResultSet\u4e5f\u662f\u9700\u8981\u5173\u95ed\u7684\u8d44\u6e90\uff0c\u7528try\u53ef\u4ee5\u6267\u884c\u5b8c\u5173\u95ed\u6216\u4f7f\u7528close\u51fd\u6570\u5173\u95ed<\/p>\n\n\n\n
EX\uff1aPreparedStatement<\/p>\n\n\n\n
\u907f\u514dSQL\u6ce8\u5165\uff0c\u4f7f\u7528Java\u5bf9\u6570\u636e\u5e93\u8fdb\u884c\u64cd\u4f5c\u65f6\uff0c\u5fc5\u987b\u4f7f\u7528PreparedStatement\uff0c\u4e25\u7981\u4efb\u4f55\u901a\u8fc7\u53c2\u6570\u62fc\u5b57\u7b26\u4e32\u7684\u4ee3\u7801\uff01<\/p>\n\n\n\n
try (Connection conn = DriverManager.getConnection(JDBC_URL, JDBC_USER, JDBC_PASSWORD)) {\n    try (PreparedStatement ps = conn.prepareStatement(\"SELECT id, grade, name, gender FROM students WHERE gender=? AND grade=?\")) {\n        ps.setObject(1, \"M\"); \/\/ \u6ce8\u610f\uff1a\u7d22\u5f15\u4ece1\u5f00\u59cb\n        ps.setObject(2, 3);\n        try (ResultSet rs = ps.executeQuery()) {\n            while (rs.next()) {\n                long id = rs.getLong(\"id\");\n                long grade = rs.getLong(\"grade\");\n                String name = rs.getString(\"name\");\n                String gender = rs.getString(\"gender\");\n            }\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
Update\u6570\u636e\u540c\u7406<\/p>\n\n\n\n
try (Connection conn = DriverManager.getConnection(JDBC_URL, JDBC_USER, JDBC_PASSWORD)) {\n    try (PreparedStatement ps = conn.prepareStatement(\n            \"INSERT INTO students (id, grade, name, gender) VALUES (?,?,?,?)\")) {\n        ps.setObject(1, 999); \/\/ \u6ce8\u610f\uff1a\u7d22\u5f15\u4ece1\u5f00\u59cb\n        ps.setObject(2, 1); \/\/ grade\n        ps.setObject(3, \"Bob\"); \/\/ name\n        ps.setObject(4, \"M\"); \/\/ gender\n        int n = ps.executeUpdate(); \/\/ 1\n    }\n}<\/code><\/pre>\n\n\n\n
\u63d2\u5165\u6570\u636e\u5e76\u83b7\u5f97\u4e3b\u952e<\/p>\n\n\n\n
try (Connection conn = DriverManager.getConnection(JDBC_URL, JDBC_USER, JDBC_PASSWORD)) {\n    try (PreparedStatement ps = conn.prepareStatement(\n            \"INSERT INTO students (grade, name, gender) VALUES (?,?,?)\",\n            Statement.RETURN_GENERATED_KEYS)) {\n        ps.setObject(1, 1); \/\/ grade\n        ps.setObject(2, \"Bob\"); \/\/ name\n        ps.setObject(3, \"M\"); \/\/ gender\n        int n = ps.executeUpdate(); \/\/ 1\n        try (ResultSet rs = ps.getGeneratedKeys()) {\n            if (rs.next()) {\n                long id = rs.getLong(1); \/\/ \u6ce8\u610f\uff1a\u7d22\u5f15\u4ece1\u5f00\u59cb\n            }\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
5 Batch<\/p>\n\n\n\n
\u63d0\u5347\u6279\u91cf\u5199\u5165\u901f\u5ea6<\/p>\n\n\n\n
try (PreparedStatement ps = conn.prepareStatement(\"INSERT INTO students (name, gender, grade, score) VALUES (?, ?, ?, ?)\")) {\n    \/\/ \u5bf9\u540c\u4e00\u4e2aPreparedStatement\u53cd\u590d\u8bbe\u7f6e\u53c2\u6570\u5e76\u8c03\u7528addBatch():\n    for (Student s : students) {\n        ps.setString(1, s.name);\n        ps.setBoolean(2, s.gender);\n        ps.setInt(3, s.grade);\n        ps.setInt(4, s.score);\n        ps.addBatch(); \/\/ \u6dfb\u52a0\u5230batch\n    }\n    \/\/ \u6267\u884cbatch:\n    int[] ns = ps.executeBatch();\n    for (int n : ns) {\n        System.out.println(n + \" inserted.\"); \/\/ batch\u4e2d\u6bcf\u4e2aSQL\u6267\u884c\u7684\u7ed3\u679c\u6570\u91cf\n    }\n}<\/code><\/pre>\n\n\n\n
6 \u8fde\u63a5\u6c60<\/p>\n\n\n\n
JDBC\u8fde\u63a5\u6c60 - \u5ed6\u96ea\u5cf0\u7684\u5b98\u65b9\u7f51\u7ad9 (liaoxuefeng.com)<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
JDBC\u4f7f\u7528<\/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-548","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\/548","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=548"}],"version-history":[{"count":3,"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/posts\/548\/revisions"}],"predecessor-version":[{"id":583,"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/posts\/548\/revisions\/583"}],"wp:attachment":[{"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/media?parent=548"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/categories?post=548"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gislxz.com\/index.php\/wp-json\/wp\/v2\/tags?post=548"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}