java 实现输出随机图片实例代码_Java教程

java 实现输出随机图片实例代码

2020-11-11 16:51Alex_zhuang Java教程

这篇文章主要介绍了java 实现输出随机图片实例代码的相关资料,需要的朋友可以参考下

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

									   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()); 

									}