输出随机图片

来源：互联网发布：刻录光碟的软件编辑：程序博客网时间：2024/05/17 03:10

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

        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());}