java数据库登陆界面代码

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class LoginFrame extends JFrame {
    private JTextField usernameField;
    private JPasswordField passwordField;
    private JButton loginButton;

    public LoginFrame() {
        setTitle("Login");
        setSize(300, 150);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);

        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(3, 2));

        JLabel userLabel = new JLabel("Username:");
        usernameField = new JTextField();
        JLabel passLabel = new JLabel("Password:");
        passwordField = new JPasswordField();
        loginButton = new JButton("Login");

        panel.add(userLabel);
        panel.add(usernameField);
        panel.add(passLabel);
        panel.add(passwordField);
        panel.add(new JLabel()); // Empty label for layout
        panel.add(loginButton);

        loginButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String username = usernameField.getText();
                String password = new String(passwordField.getPassword());
                if (validateUser(username, password)) {
                    JOptionPane.showMessageDialog(LoginFrame.this, "Login Successful!");
                } else {
                    JOptionPane.showMessageDialog(LoginFrame.this, "Invalid Credentials!", "Error", JOptionPane.ERROR_MESSAGE);
                }
            }
        });

        add(panel);
    }

    private boolean validateUser(String username, String password) {
        // Backend logic to validate user against database
        return DatabaseConnection.validate(username, password);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new LoginFrame().setVisible(true);
            }
        });
    }
}

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DatabaseConnection {
    private static final String DB_URL = "jdbc:mysql://localhost:3306/mydatabase";
    private static final String USER = "dbuser";
    private static final String PASS = "dbpass";

    public static boolean validate(String username, String password) {
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            conn = DriverManager.getConnection(DB_URL, USER, PASS);
            String sql = "SELECT * FROM users WHERE username=? AND password=?";
            stmt = conn.prepareStatement(sql);
            stmt.setString(1, username);
            stmt.setString(2, password);
            rs = stmt.executeQuery();
            return rs.next(); // If there is a next row, the credentials are valid
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        } finally {
            try {
                if (rs != null) rs.close();
                if (stmt != null) stmt.close();
                if (conn != null) conn.close();
            } catch (SQLException se) {
                se.printStackTrace();
            }
        }
    }
}