2024.10.11

 

源代码（主要）：

import java.sql.*;

import java.util.ArrayList;

import java.util.List;

 

public class UserDAO {

    private static final String JDBC_DRIVER = "com.mysql.cj.jdbc.Driver";

    private static final String DB_URL = "jdbc:mysql://localhost:3306/login?useSSL=false&characterEncoding=utf8&serverTimezone=UTC";

    private static final String USER = "123456";

    private static final String PASS = "123456";

 

    public UserDAO() {

        try {

            Class.forName(JDBC_DRIVER);

        } catch (ClassNotFoundException e) {

            e.printStackTrace();

        }

    }

 

    public User authenticate(String username, String password) {

        String sql = "SELECT * FROM users WHERE username = ? AND password = ?";

        try (Connection conn = DriverManager.getConnection(DB_URL, USER, PASS);

             PreparedStatement stmt = conn.prepareStatement(sql)) {

            stmt.setString(1, username);

            stmt.setString(2, password);

            ResultSet rs = stmt.executeQuery();

            if (rs.next()) {

                int id = rs.getInt("id");

                return new User(id, username, password);

            }

        } catch (SQLException e) {

            e.printStackTrace();

        }

        return null;

}

 

   public static void main(String[] args) throws SQLException {

        Connection conn = getConn();

        PreparedStatement pstmt = null;

        ResultSet rs = null;

        String sql ="select * from user";

        pstmt = conn.prepareStatement(sql);

        rs = pstmt.executeQuery();

        if(rs.next()){

            System.out.println("连接成功");

        }else{

            System.out.println("连接失败");

        }

    }

 

   public  void  validate(String username,String password)

    {

 

        if(username.trim().length()==0||password.trim().length()==0){

            JOptionPane.showMessageDialog(null, "用户名,密码不允许为空");

 

            return;

        }

 

        if(dao.findUser(username, password))

        {

 

            JOptionPane.showMessageDialog(null, "登录成功！");

 

 

        }else {

            JOptionPane.showMessageDialog(null, "用户名或密码错误");

 

        }

 

    }

 

public class User {

    private int id;

    private String username;

    private String password;

 

 

    public User(int id, String username, String password) {

        this.id = id;

        this.username = username;

        this.password = password;

    }

 

    public int getId() {

        return id;

    }

 

    public String getUsername() {

        return username;

    }

 

    public String getPassword() {

        return password;

    }