java 实现输出随机图片实例代码

时间:2022-09-22 07:54:00

java  实现输出随机图片实例代码

输出随机图片(CAPTCHA图像):Completely Automated Public Turing Test to Tell Computers and Humans Apart (全自动区分计算机和人类的测试)

相关主要类(JDK 查看API)

BufferedImage:内存图像
Graphics:画笔
ImageIO:输出图像

放在html页面上<img src/>

注意:浏览器默认会缓存图片

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   public static int WIDTH = 120;
public static int HEIGHT = 25;
 
public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
 
  response.setContentType("text/html");
  //创建内存图像
  BufferedImage image = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);
  //勾勒图像
  Graphics graphics = image.getGraphics();
  //设置背景
  graphics.setColor(Color.WHITE);
  graphics.fillRect(0, 0, WIDTH, HEIGHT);
  //设置边框
  graphics.setColor(Color.BLUE);
  graphics.drawRect(1, 1, WIDTH-2, HEIGHT-2);
  //画干扰线
  graphics.setColor(Color.YELLOW);
  for(int i=0;i<8;i++){
    int xStart = new Random().nextInt(WIDTH);
    int yStart = new Random().nextInt(HEIGHT);
    int xEnd = new Random().nextInt(WIDTH);
    int yEnd = new Random().nextInt(HEIGHT);
    graphics.drawLine(xStart, yStart, xEnd, yEnd);
  }
  //写随机数
  graphics.setColor(Color.RED);
  int x = 5;
  for(int i=0;i<4;i++){
    graphics.drawString(new Random().nextInt(9)+"", x, 20);
    x+=30;
  }
  response.setContentType("image/jpeg");//设置响应格式
  ImageIO.write(image, "jpeg", response.getOutputStream());
   
}

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原文链接:http://blog.csdn.net/alex_zhuang/article/details/7249850