用户注册与登录界面java源码（带验证码）

        import javax.swing.*;
        import java.awt.*;
        import java.util.Random;

      public class RegistrationSystem extends JFrame {
        private final JTextField usernameTextField;
        private final JPasswordField passwordField;
        private final JTextField captchaTextField;
        private final JLabel captchaLabel;
        private JLabel feedbackLabel;
        private String captcha;
        }

       public RegistrationSystem() {
        setTitle("Registration System");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(400, 300);
        setLayout(new GridLayout(6, 2));
        }

    // 注册页面
    JLabel usernameLabel = new JLabel("Username:");
    usernameTextField = new JTextField();
    JLabel passwordLabel = new JLabel("Password:");
    passwordField = new JPasswordField();
    JLabel captchaInputLabel = new JLabel("Captcha:");
    captchaTextField = new JTextField();
    captchaLabel = new JLabel();
    JButton refreshCaptchaButton = new JButton("Refresh Captcha");
    JButton actionButton = new JButton("Register");

    // 验证码生成与刷新
    generateCaptcha();
    refreshCaptchaButton.addActionListener(e -> generateCaptcha());

    // 按钮点击事件
    actionButton.addActionListener(e -> {
        String username = usernameTextField.getText();
        String password = new String(passwordField.getPassword());
        String inputCaptcha = captchaTextField.getText();

        // 验证码验证
        if (!inputCaptcha.equals(captcha)) {
            feedbackLabel.setText("Invalid captcha. Please try again.");
            generateCaptcha();
            return;
        }

        // 用户名和密码验证
        if (!isValidUsername(username) || !isValidPassword(password)) {
            feedbackLabel.setText("Invalid username or password. Please try again.");
            generateCaptcha();
            return;
        }

        // 根据按钮的文本判断是注册还是登录操作
        if (actionButton.getText().equals("Register")) {
            // 模拟注册成功，跳转到登录界面
            JOptionPane.showMessageDialog(null, "Registration successful!");
            showLoginPage();
        } else if (actionButton.getText().equals("Login")) {
            // 模拟登录成功，显示欢迎界面
            JOptionPane.showMessageDialog(null, "Login successful!");
            showWelcomePage(username);
        }
    });

    // 添加组件到注册页面
    add(usernameLabel);
    add(usernameTextField);
    add(passwordLabel);
    add(passwordField);
    add(captchaInputLabel);
    add(captchaTextField);
    add(captchaLabel);
    add(refreshCaptchaButton);
    add(actionButton);

    // 反馈信息标签
    feedbackLabel = new JLabel();
    add(feedbackLabel);

    // 默认显示注册页面
    showRegisterPage();
}

// 显示注册页面
private void showRegisterPage() {
    setTitle("Registration Page");
    setVisible(true);
    feedbackLabel.setText("");
    usernameTextField.setText("");
    passwordField.setText("");
    captchaTextField.setText("");
    captchaLabel.setText("");
    JButton actionButton = (JButton) getContentPane().getComponent(8);
    actionButton.setText("Register");
}

// 显示登录页面
private void showLoginPage() {
    setTitle("Login Page");
    setVisible(true);
    feedbackLabel.setText("");
    usernameTextField.setText("");
    passwordField.setText("");
    captchaTextField.setText("");
    captchaLabel.setText("");
    JButton actionButton = (JButton) getContentPane().getComponent(8);
    actionButton.setText("Login");
}

// 显示欢迎界面
private void showWelcomePage(String username) {
    setTitle("Welcome");
    setSize(300, 200);
    getContentPane().removeAll();
    getContentPane().setLayout(new FlowLayout());
    JLabel welcomeLabel = new JLabel("Hello " + username + "! Current time is: " + getCurrentTime());
    getContentPane().add(welcomeLabel);
    revalidate();
    repaint();
}

// 生成验证码
private void generateCaptcha() {
    String characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
    StringBuilder sb = new StringBuilder();
    Random random = new Random();
    for (int i = 0; i < 8; i++) {
        int index = random.nextInt(characters.length());
        sb.append(characters.charAt(index));
    }
    captcha = sb.toString();
    captchaLabel.setText(captcha);
}

// 验证用户名格式是否有效
private boolean isValidUsername(String username) {
    return username.matches("[a-zA-Z0-9]{8,20}");
}

// 验证密码格式是否有效
private boolean isValidPassword(String password) {
    return password.matches("[a-zA-Z0-9]{8,16}");
}

// 获取当前时间
private String getCurrentTime() {
    return new java.util.Date().toString();
}

public static void main(String[] args) {
    SwingUtilities.invokeLater(RegistrationSystem::new);
}

}