请给代码加上相应的中文注释

好的，以下是加上中文注释的代码：

import java.sql.*;

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

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

    public Login() {
        super("Login");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new GridLayout(4, 2, 10, 10));
        setResizable(false);

        // 标题
        titleLabel = new JLabel("游戏登录", SwingConstants.CENTER);
        titleLabel.setFont(new Font("Arial", Font.BOLD, 24));
        add(titleLabel);

        // 用户名
        usernameLabel = new JLabel("用户名:", SwingConstants.RIGHT);
        add(usernameLabel);

        usernameField = new JTextField(20);
        add(usernameField);

        // 密码
        passwordLabel = new JLabel("密码:", SwingConstants.RIGHT);
        add(passwordLabel);

        passwordField = new JPasswordField(20);
        add(passwordField);

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

        // 注册按钮
        registerButton = new JButton("注册");
        registerButton.addActionListener(this);
        add(registerButton);

        pack();
        setLocationRelativeTo(null);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        String action = e.getActionCommand();
        if (action.equals("登录")) {
            String username = usernameField.getText();
            String password = new String(passwordField.getPassword());

            String url = "jdbc:mysql://localhost:3306/game"; // 数据库连接字符串
            String user = "root"; // 数据库用户名
            String pass = "123456"; // 数据库密码

            try {
                // 连接数据库
                Connection conn = DriverManager.getConnection(url, user, pass);
                Statement stmt = conn.createStatement();
                // 查询用户信息是否正确
                ResultSet rs = stmt.executeQuery("SELECT * FROM users WHERE username='" + username + "' AND password='" + password + "'");
                if (rs.next()) {
                    JOptionPane.showMessageDialog(this, "登录成功！");
                } else {
                    JOptionPane.showMessageDialog(this, "用户名或密码不正确！");
                }
                stmt.close();
                conn.close();
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        } else if (action.equals("注册")) {
            // 实现注册逻辑
        }
    }

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

希望这份代码能对您有所帮助。