public tt() { // TODO Auto-generated constructor stub try { Class.forName("com.mysql.jdbc.Driver");  Connection conn = (Connection) DriverManager.getConnection(Driver, username,password); java.sql.Statement stmt = conn.createStatement();  ResultSet rs=stmt.executeQuery("select * from aa1");  int a=0; while(rs.next()){ System.out.println(String.valueOf(a)+rs.getString("val")); a++; }     } catch (Exception e) { e.printStackTrace(); } }}

// 1. 注册驱动  try {   Class.forName("com.mysql.jdbc.Driver");  } catch (ClassNotFoundException e) {   // TODO Auto-generated catch block   e.printStackTrace();  }// Mysql 的驱动    // 2. 获取数据库的连接  java.sql.Connection conn = java.sql.DriverManager.getConnection(    "jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=GBK", "root", null);    // 3. 获取表达式  java.sql.Statement stmt = conn.createStatement();      // 执行插入数据的 SQL  stmt.executeUpdate("insert into MyUser(username, password) values('JDBC 中文测试', '密码')");      // 4. 执行 SQL  java.sql.ResultSet rs = stmt.executeQuery("select * from MyUser");    // 5. 显示结果集里面的数据  while(rs.next()) {   System.out.println(rs.getInt(1));   System.out.println(rs.getString("username"));   System.out.println(rs.getString("password"));   System.out.println();  }    // 6. 释放资源  rs.close();  stmt.close();  conn.close();