import javax.swing.; import java.awt.; import java.awt.event.*; public class Login extends JFrame implements ActionListener { private JLabel usernameLabel, passwordLabel; private JTextField usernameField; private JPasswordField passwordField; private JButton loginButton, exitButton; public Login() { super("登录页面"); this.setLayout(new GridLayout(3, 2)); usernameLabel = new JLabel("用户名："); this.add(usernameLabel); usernameField = new JTextField(10); this.add(usernameField); passwordLabel = new JLabel("密码："); this.add(passwordLabel); passwordField = new JPasswordField(10); this.add(passwordField); loginButton = new JButton("登录"); loginButton.addActionListener(this); this.add(loginButton); exitButton = new JButton("退出"); exitButton.addActionListener(this); this.add(exitButton); this.pack(); this.setLocationRelativeTo(null); this.setVisible(true); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } public void actionPerformed(ActionEvent e) { if (e.getSource() == loginButton) { String username = usernameField.getText(); String password = new String(passwordField.getPassword()); if (username.equals("admin") && password.equals("admin")) { JOptionPane.showMessageDialog(this, "登录成功！"); new FiveChessFrame(); this.dispose(); } else { JOptionPane.showMessageDialog(this, "用户名或密码错误！"); } } else if (e.getSource() == exitButton) { System.exit(0); } } public static void main(String[] args) { new Login(); } }给这段代码排版好看一点，美化一下

好的，下面是美化过的代码：

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

public class Login extends JFrame implements ActionListener {
    private JLabel usernameLabel, passwordLabel;
    private JTextField usernameField;
    private JPasswordField passwordField;
    private JButton loginButton, exitButton;

    public Login() {
        super("登录页面");
        this.setLayout(new GridLayout(3, 2));

        usernameLabel = new JLabel("用户名：");
        this.add(usernameLabel);
        usernameField = new JTextField(10);
        this.add(usernameField);

        passwordLabel = new JLabel("密码：");
        this.add(passwordLabel);
        passwordField = new JPasswordField(10);
        this.add(passwordField);

        loginButton = new JButton("登录");
        loginButton.addActionListener(this);
        this.add(loginButton);

        exitButton = new JButton("退出");
        exitButton.addActionListener(this);
        this.add(exitButton);

        this.pack();
        this.setLocationRelativeTo(null);
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == loginButton) {
            String username = usernameField.getText();
            String password = new String(passwordField.getPassword());

            if (username.equals("admin") && password.equals("admin")) {
                JOptionPane.showMessageDialog(this, "登录成功！");
                new FiveChessFrame();
                this.dispose();
            } else {
                JOptionPane.showMessageDialog(this, "用户名或密码错误！");
            }
        } else if (e.getSource() == exitButton) {
            System.exit(0);
        }
    }

    public static void main(String[] args) {
        new Login();
    }
}

这是一个简单的登录页面，包括用户名、密码输入框、登录和退出按钮。当用户输入正确的用户名和密码时，点击登录按钮会弹出提示框，提示用户登录成功，并且打开一个六子棋的窗口；否则弹出提示框，提示用户名或密码错误。