Swing图形界面实现可动态刷新的验证码

import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Toolkit; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.util.Random; import javax.swing.JFrame;  public class CheckCode extends JFrame { private static Random random = new Random(); private int width = 53;//验证码宽度 private int height =25;//验证码高度 private int font_size = 20;//验证码颜色 private int x = 100;//验证码所在窗体X坐标 private int y = 100;//验证码所在窗体Y坐标 private int jam = 5;//干扰元素 建议使用 4~7 之间的数字 private String code = "";//保存验证码  public CheckCode(){//初始化窗体信息 super("验证码"); setVisible(true); setBounds((Toolkit.getDefaultToolkit().getScreenSize().width-300)/2, (Toolkit.getDefaultToolkit().getScreenSize().height-300)/2, 300, 200); setDefaultCloseOperation(EXIT_ON_CLOSE); addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { repaint(); } }); }  public Color getRandomColor(){//获得随机颜色 int R=random.nextInt(255),G=random.nextInt(255),B=random.nextInt(255); return new Color(R,G,B); }  public String getRandomString(){//获得验证码 int num = random.nextInt(9); code = num+""; return num+""; }  public void checkCode(Graphics g){// 绘画验证码 drawBorder(g);  drawCode(g); drawJam(g); }  public void drawBorder(Graphics g){//绘画边框和背景 Color gc = g.getColor(); g.setColor(Color.WHITE); g.fillRect(x, y, width, height); g.setColor(Color.BLACK); g.drawRect(x, y, width, height); g.setColor(gc); }  public void drawCode(Graphics g){//绘画验证码内容 Color gc = g.getColor(); for(int i=0;i<4;i++){ g.setColor(getRandomColor()); g.setFont(new Font("宋体",Font.BOLD,font_size)); g.drawString(getRandomString(), x+5+(i*12), y+font_size); } g.setColor(gc); }  public void drawJam(Graphics g){//绘画干扰元素 Color gc = g.getColor(); for(int i=0;i<jam;i++){ g.setColor(getRandomColor()); g.drawLine(x+random.nextInt(width), y+random.nextInt(height), x+random.nextInt(width), y+random.nextInt(height)); } g.setColor(gc); }  public void paint(Graphics g) { Color c = g.getColor(); g.drawString("单击可刷新验证码", 30, 50); checkCode(g); g.setColor(c); }  public static void main(String[] args) { new CheckCode(); } }