生成数字和字母组合的验证码

来源：互联网发布：滴滴截图造假软件编辑：程序博客网时间：2024/05/17 09:12

//生成数字和字母组合的验证码
public class ResponseDemo3 extends HttpServlet {
private static final long serialVersionUID =1L;
private int WIDTH=140;
private int HEIGHT=35;
public void doGet(HttpServletRequest request,HttpServletResponse response)
   throwsServletException, IOException {
  BufferedImage image=newBufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);
  Graphicsg=image.getGraphics();

  //1、设置背景色
  setBackGround(g);

  //2、设置边框
  serBorder(g);

  //3、画干扰线
  drawRandomLine(g);

  //4、写随机数
  drawRandomNum((Graphics2D)g);

  //禁止图像缓存。
       response.setHeader("Pragma", "no-cache");
       response.setHeader("Cache-Control","no-cache");
       response.setDateHeader("Expires", 0);

  //5、图形写给浏览器
  response.setContentType("text/jpeg");
  ImageIO.write(image, "jpg",response.getOutputStream());
}

private void setBackGround(Graphics g) {
  g.setColor(getRandColor(190,230));
  g.fillRect(0, 0, WIDTH,HEIGHT);
}

private void serBorder(Graphics g) {
  g.setColor(Color.BLACK);
  g.drawRect(1, 1, WIDTH-2,HEIGHT-2);
}

private void drawRandomLine(Graphics g) {
  g.setColor(Color.GRAY);
  for(inti=0;i<4;i++){
   int x1=newRandom().nextInt(WIDTH);
   int y1=newRandom().nextInt(HEIGHT);

   int x2=newRandom().nextInt(WIDTH);
   int y2=newRandom().nextInt(HEIGHT);

   g.drawLine(x1,y1, x2, y2);
  }
}

private void drawRandomNum(Graphics2D g){
  g.setColor(getRandColor(20,80));

  //设置字体的大小
  g.setFont(newFont("宋体",Font.BOLD,30));
  Stringbase="abcdefghijklmnopqrstuvwxyz0123456789";
  int x=10;
  for(inti=0;i<6;i++){
   intdegree=new Random().nextInt()0;//角度范围在-30-30
   Stringch=base.charAt(new Random().nextInt(base.length()))+"";

   //设置旋转角度
   g.rotate(degree*Math.PI/180,x,20);
   g.drawString(ch,x, 25);

   //每次旋转完后再把角度设置成原来的
   g.rotate(-degree*Math.PI/180,x,20);
   x+=20;
  }
}

//给定范围获得随机颜色
Color getRandColor(int fc, int bc){
       Random random = new Random();
       if (fc > 255)
           fc = 255;
       if (bc > 255)
           bc = 255;
       int r = fc + random.nextInt(bc - fc);
       int g = fc + random.nextInt(bc - fc);
       int b = fc + random.nextInt(bc - fc);
       return new Color(r, g, b);
   }

public void doPost(HttpServletRequest request,HttpServletResponse response)
throwsServletException, IOException {

doGet(request,response);
}

}

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