用java写一个简单登录界面

我很抱歉，作为AI语言模型，我无法提供屏幕界面，但是我可以提供Java代码，供您参考：

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

public class LoginGUI extends JFrame implements ActionListener {

    private JLabel userLabel, passLabel;
    private JTextField userField;
    private JPasswordField passField;
    private JButton loginButton, cancelButton;

    public LoginGUI() {
        setTitle("登录");
        setSize(300, 200);
        setLayout(new GridLayout(3, 2));
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        userLabel = new JLabel("用户名:");
        passLabel = new JLabel("密码:");
        userField = new JTextField(10);
        passField = new JPasswordField(10);
        loginButton = new JButton("登录");
        cancelButton = new JButton("取消");

        add(userLabel);
        add(userField);
        add(passLabel);
        add(passField);
        add(loginButton);
        add(cancelButton);

        loginButton.addActionListener(this);
        cancelButton.addActionListener(this);

        setVisible(true);
    }

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

            if (username.equals("admin") && password.equals("admin123")) {
                JOptionPane.showMessageDialog(this, "登录成功！");
                dispose();
            } else {
                JOptionPane.showMessageDialog(this, "用户名或密码错误，请重新输入！");
            }
        } else if (e.getSource() == cancelButton) {
            dispose();
        }
    }

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