java语言图形用户登录界面代码

package wzb;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Panel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.util.Random;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
public class Login extends JFrame implements ActionListener {
 String userName;
 String password;
 String captcha;
 public static String randomcaptcha;
 public JLabel logoLabel, userNameLabel, passwordLabel, captchaLabel;
 public JTextField userNameInput, captchaInput;
 public JPasswordField passwordInput;
 public JButton login, logout,change;
 public Panel panel;
 public Login() {
  setTitle("µÇ¼½çÃæ");
  setSize(400, 300);
  setLocationRelativeTo(null);
  init();
  setVisible(true);
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setResizable(false);
 }
 public void init() {
  setLayout(null);
  // logoLabel= new JLabel();
  // logoLabel.setIcon(new ImageIcon("E:\\eclipse\\student3\\welcome.gif"));
  logoLabel = new JLabel(new ImageIcon("welcome.gif"));
  logoLabel.setBounds(125, 10, 150, 70);
  add(logoLabel);
  userNameLabel = new JLabel("̞:");
  userNameLabel.setBounds(90, 90, 60, 40);
  add(userNameLabel);
  userNameInput = new JTextField();
  userNameInput.setBounds(150, 100, 150, 20);
  add(userNameInput);
  passwordLabel = new JLabel("ÃÜ¡¡Âë:");
  passwordLabel.setBounds(90, 120, 60, 40);
  add(passwordLabel);
  passwordInput = new JPasswordField();
  passwordInput.setBounds(150, 130, 150, 20);
  add(passwordInput);
  captchaLabel = new JLabel("ÑéÖ¤Âë:");
  captchaLabel.setBounds(90, 150, 60, 40);
  add(captchaLabel);
  captchaInput = new JTextField();
  captchaInput.setBounds(150, 160, 70, 20);
  add(captchaInput);
  panel = new PanelDemo();
  panel.setBounds(220, 160, 80, 20);
  add(panel);
  change = new JButton("»»Ò»»»");
  change.setBounds(300, 160, 80, 20);
  change.setContentAreaFilled(false);
  change.setBorderPainted(false);
  add(change);
  login = new JButton("µÇ¼£¨L£©", new ImageIcon("login.gif"));
  login.setBounds(70, 200, 120, 30);
  login.setMnemonic(KeyEvent.VK_L);
  add(login);
  logout = new JButton("Í˳ö£¨X£©", new ImageIcon("exit.gif"));
  logout.setBounds(210, 200, 120, 30);
  logout.setMnemonic(KeyEvent.VK_X);
  add(logout);
  userNameInput.addActionListener(this);
  passwordInput.addActionListener(this);
  captchaInput.addActionListener(this);
  login.addActionListener(this);
  logout.addActionListener(this);
  change.addActionListener(this);
 }
 public void actionPerformed(ActionEvent e) {
  userName = userNameInput.getText();
  password = new String(passwordInput.getPassword());
  captcha = captchaInput.getText();
  if (e.getSource() == change) {
   panel.repaint();
  }
  if (e.getSource() == login) {
   if ((userName.equals("w")) && (password.equals("w"))) {
    if (captcha.equals(randomcaptcha)) {
     JOptionPane.showMessageDialog(this, "»¶Ó­µÇ½!");
    } else {
     JOptionPane.showMessageDialog(this, "ÑéÖ¤Âë´íÎó!");
     panel.repaint();
    }
   } else {
    JOptionPane.showMessageDialog(this, "Óû§Ãû»òÃÜÂë´íÎó!");
   }
  }
  if (e.getSource() == logout) {
   JOptionPane.showMessageDialog(this, "»¶Ó­Ï´ÎÔÙÀ´£¡");
   //System.exit(0);
   dispose();
  }
 }
 public static void main(String[] args) {
  new Login();
 }
}
class PanelDemo extends Panel {
 public void paint(Graphics g) {
  int width = 80;
  int height = 20;
  g.setColor(Color.LIGHT_GRAY);
  g.fillRect(0, 0, width, height);
  g.setColor(Color.BLACK);
  g.drawRect(0, 0, width, height);
  Random rd = new Random();
  for (int i = 0; i < 100; i++) {
   int x = rd.nextInt(width) - 2;
   int y = rd.nextInt(height) - 2;
   g.setColor(Color.RED);
   g.drawOval(x, y, 2, 2);
  }
  g.setFont(new Font("ºÚÌå", Font.BOLD, 20));
  g.setColor(Color.BLUE);
  char[] c = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();
  StringBuffer sb = new StringBuffer();
  for (int i = 0; i < 4; i++) {
   int index = rd.nextInt(c.length);
   sb.append(c[index] + " ");
  }
  g.drawString(sb.toString(), 0, 18);
  String str = sb.toString().replaceAll(" ", "");
  Login.randomcaptcha = str;
 }
}