如何在java登录数据库中查找重复的值(用户名、密码)？

import java.sql.*;

public class DuplicateValueFinder {
    public static void main(String[] args) {
        Connection connection = null;
        Statement statement = null;
        ResultSet resultSet = null;

        try {
            // 1. 导入数据库驱动程序
            Class.forName("com.mysql.jdbc.Driver");

            // 2. 建立数据库连接
            String url = "jdbc:mysql://localhost:3306/mydatabase";
            String username = "root";
            String password = "password";
            connection = DriverManager.getConnection(url, username, password);

            // 3. 创建查询语句
            String query = "SELECT username, password, COUNT(*) FROM users GROUP BY username, password HAVING COUNT(*) > 1";

            // 4. 执行查询语句
            statement = connection.createStatement();
            resultSet = statement.executeQuery(query);

            // 5. 遍历结果集
            while (resultSet.next()) {
                String username = resultSet.getString("username");
                String password = resultSet.getString("password");
                int count = resultSet.getInt(3);

                System.out.println("重复的值：");
                System.out.println("用户名：" + username);
                System.out.println("密码：" + password);
                System.out.println("重复次数：" + count);
                System.out.println("--------------------");
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            // 6. 关闭连接和资源
            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (statement != null) {
                    statement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}