1.主程序
1 package com.xyyz.jdbc; 2 3 import java.sql.Connection; 4 import java.sql.DriverManager; 5 import java.sql.PreparedStatement; 6 import java.sql.ResultSet; 7 8 import com.xyyz.utils.JDBCUtils; 9 10 public class JDBCDemo { 11 12 public static void main(String[] args) throws Exception { 13 query(); 14 insert(); 15 query(); 16 update(); 17 query(); 18 delete(); 19 query(); 20 } 21 22 /** 23 * 查询代码 24 * 25 * @throws Exception 26 */ 27 public static void query() throws Exception { 28 Connection connection = JDBCUtils.getConnection(); 29 // 获取数据库连接 30 String sql = "select * from jdbctestdata"; 31 // 获取预编译对象 32 PreparedStatement prepareStatement = connection.prepareStatement(sql); 33 // 执行sql语句 34 ResultSet resultSet = prepareStatement.executeQuery(); 35 // 遍历打印sql语句 36 while (resultSet.next()) { 37 System.out.println(resultSet.getInt(1) + "--" + resultSet.getString(2)); 38 } 39 // 关闭释放资源 40 JDBCUtils.closeAll(resultSet, prepareStatement, connection); 41 } 42 43 /** 44 * 插入数据 45 */ 46 public static void insert() throws Exception { 47 // 获取数据库连接 48 Connection connection = JDBCUtils.getConnection(); 49 String sql = "insert into jdbctestdata value(?,?,?)"; 50 // 获取预编译对象 51 PreparedStatement prepare = connection.prepareStatement(sql); 52 prepare.setString(1, "6"); 53 prepare.setString(2, "小白"); 54 prepare.setString(3, "30"); 55 int i = prepare.executeUpdate(); 56 System.out.println("i=" + i); 57 // 关闭释放资源 58 JDBCUtils.closeAll(null, prepare, connection); 59 } 60 61 /** 62 * 更新数据 63 */ 64 public static void update() throws Exception { 65 66 // 获取数据库连接 67 Connection connection = JDBCUtils.getConnection(); 68 String sql = "update jdbctestdata set name=? , age=? where id=?"; 69 // 获取预编译对象 70 PreparedStatement prepare = connection.prepareStatement(sql); 71 prepare.setString(1, "小红"); 72 prepare.setString(2, "20"); 73 prepare.setString(3, "6"); 74 int i = prepare.executeUpdate(); 75 System.out.println("i=" + i); 76 // 执行sql语句 77 JDBCUtils.closeAll(null, prepare, connection); 78 } 79 80 /** 81 * 删除数据 82 */ 83 public static void delete() throws Exception { 84 // 获取数据库连接 85 Connection connection = JDBCUtils.getConnection(); 86 String sql = "delete from jdbctestdata where id = ?"; 87 // 获取预编译对象 88 PreparedStatement prepare = connection.prepareStatement(sql); 89 prepare.setString(1, "6"); 90 int i = prepare.executeUpdate(); 91 System.out.println("i=" + i); 92 // 执行sql语句 93 JDBCUtils.closeAll(null, prepare, connection); 94 } 95 96 }
2.工具类
1 package com.xyyz.utils; 2 3 import java.sql.Connection; 4 import java.sql.DriverManager; 5 import java.sql.PreparedStatement; 6 import java.sql.ResultSet; 7 import java.sql.SQLException; 8 import java.sql.Statement; 9 import java.util.Objects; 10 11 public class JDBCUtils { 12 // 连接数据需要的参数 13 private static String url = "jdbc:mysql:///jdbctestdata"; 14 private static String user = "root"; 15 private static String password = "root"; 16 17 static { 18 // 注册驱动 19 try { 20 Class.forName("com.mysql.jdbc.Driver"); 21 } catch (ClassNotFoundException e) { 22 System.out.println("没有加masql的jar包"); 23 } 24 25 } 26 27 /** 28 * 获取connection 29 */ 30 public static Connection getConnection() throws SQLException { 31 return DriverManager.getConnection(url, user, password); 32 } 33 34 // 关闭资源的方法 35 public static void closeAll(ResultSet resultSet, PreparedStatement prepareStatement, Connection connection) { 36 // 关闭资源 37 if (resultSet != null) { 38 try { 39 resultSet.close(); 40 } catch (Exception e) { 41 e.printStackTrace(); 42 } 43 resultSet = null; 44 } 45 if (prepareStatement != null) { 46 try { 47 prepareStatement.close(); 48 } catch (Exception e) { 49 e.printStackTrace(); 50 } 51 prepareStatement = null; 52 } 53 if (connection != null) { 54 try { 55 connection.close(); 56 } catch (Exception e) { 57 e.printStackTrace(); 58 } 59 connection = null; 60 } 61 } 62 }
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