使用java代码编写基于JDBC的数据库操作，并且建立用户登录界面的源代码

import java.sql.*; public class case2 { static final String JDBC_DRIVER = "com.mysql.cj.jdbc.Driver"; static final String DB_URL = "jdbc:mysql://localhost:3306/student"; static final String USER = "root"; // 替换为你的用户名 static final String PASS = "123456"; // 替换为你的密码 public static void main(String[] args) { Connection conn = null; try { // 加载 JDBC 驱动 Class.forName(JDBC_DRIVER); // 建立连接 conn = DriverManager.getConnection(DB_URL, USER, PASS); // 创建 tb_account 表 String createTableSQL = "CREATE TABLE IF NOT EXISTS `tb_account` (" + " `user_id` CHAR(8) NOT NULL," + " `user_name` CHAR(10) NOT NULL," + " `password` CHAR(10) NOT NULL DEFAULT '123456'," + " PRIMARY KEY (`user_id`)" + ")"; try (Statement statement = conn.createStatement()) { statement.executeUpdate(createTableSQL); System.out.println("Table 'tb_account' created successfully."); } // 插入数据到 tb_account 表 String insertSQL = "INSERT INTO `tb_account` (`user_id`, `user_name`)" + " SELECT `stu_id`, `stu_name` FROM `tb_student`"; try (Statement statement = conn.createStatement()) { int rowsAffected = statement.executeUpdate(insertSQL); if (rowsAffected > 0) { System.out.println("Data inserted successfully into 'tb_account'."); } } } catch (SQLException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } finally { // 关闭数据库连接 if (conn != null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } } }