验证码登陆界面

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JLabel;
import java.awt.Dimension;
import javax.swing.JPasswordField;
public class VerificationCode extends JFrame implements ActionListener{
 
 private JLabel usernameLabel;
 private JTextField usernameTextField;
 private JLabel passwordLabel;
 private JTextField passwordField;
 private JLabel VerificationCodeLabel;
 private JTextField VerificationCodeField;
 private JButton ramstr;
 private JLabel haha;
 private JButton bu1;
 private JButton bu2;
 
 public void add(JFrame frame) {
  
  frame.setTitle("请登录");
  frame.setLayout(null);
  
  usernameLabel =new JLabel("登录名");
  usernameLabel.setBounds(60, 40, 70, 30);
  usernameLabel.setFont(new Font("黑体",Font.BOLD,16));
  usernameTextField =new JTextField();
  usernameTextField.setBounds(140,45,120,20);
  usernameTextField.setFont(new Font("宋体",Font.BOLD,16));
  usernameTextField.setHorizontalAlignment(JTextField.CENTER);
  
  passwordLabel =new JLabel("密码");
  passwordLabel.setBounds(60, 70, 70, 30);
  passwordLabel.setFont(new Font("黑体",Font.BOLD,16));
  passwordField =new JPasswordField();
  passwordField.setBounds(140,75,120,20);
  passwordField.setFont(new Font("宋体",Font.BOLD,16));
  haha =new JLabel("忘记用户名/密码？");
  haha.setForeground(Color.blue);
  haha.setBounds(260, 70, 140, 30);
  haha.setFont(new Font("汉真广标",Font.BOLD,10));
  
  VerificationCodeLabel =new JLabel("验证码");
  VerificationCodeLabel.setBounds(60, 100, 70, 30);
  VerificationCodeLabel.setFont(new Font("黑体",Font.BOLD,16));
  VerificationCodeField =new JTextField();
  VerificationCodeField.setBounds(140,105,60,20);
  VerificationCodeField.setFont(new Font("宋体",Font.BOLD,16));
  
  ramstr =new JButton();
  ramstr.setText(ram());
  ramstr.setBackground(Color.black);
  ramstr.setForeground(Color.CYAN);
  ramstr.setBounds(220, 100, 100, 30);
  ramstr.setFont(new Font("汉真广标",Font.BOLD,16));
  ramstr.addActionListener(this);
  ramstr.setToolTipText("眼瞎？换一张？");
  getContentPane().add(ramstr);
  
  bu1=new JButton();
  bu1.setText("登陆");
  bu1.setBackground(Color.ORANGE);
  bu1.setForeground(Color.white);
  bu1.setBounds(120, 145, 120, 30);
  getContentPane().add(bu1);
  bu2=new JButton();
  bu2.setText("快速注册");
  bu2.setBounds(120, 185, 120, 30);
  getContentPane().add(bu2);
  
  frame.add(usernameLabel);
  frame.add(usernameTextField);
  frame.add(passwordLabel);
  frame.add(passwordField);
  frame.add(haha);
  frame.add(VerificationCodeLabel);
  frame.add(VerificationCodeField);
  frame.add(ramstr);
  frame.add(bu1);
  frame.add(bu2);
 }
 public String ram() {
  String result = "";
  for(int i = 0 ; i < 6 ; i ++)
  {
   int intVal = (int)(Math.random() * 26 + 97);
   result = result + (char)intVal;
  }
  return result;
 }
 public void actionPerformed(ActionEvent e) {
  ramstr.setText(ram());
 }
 public static void main(String []args) {
  JFrame frame =new JFrame("JFrame窗口");
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.setSize(400,300);
  Dimension displaySize =Toolkit.getDefaultToolkit().getScreenSize();
  Dimension frameSize= frame.getSize();
  if(frameSize.width>displaySize.width)
   frameSize.width=displaySize.width;
  if(frameSize.height>displaySize.height)
   frameSize.height=displaySize.height;
  frame.setLocation((displaySize.width-frameSize.width),(displaySize.height-frameSize.height));
  VerificationCode Swing=new VerificationCode();
  Swing.add(frame);
  frame.setVisible(true);
 }
 }