java 实现输出随机图片实例代码
java 实现输出随机图片实例代码
输出随机图片(CAPTCHA图像):CompletelyAutomatedPublicTuringTesttoTellComputersandHumansApart(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
注意:浏览器默认会缓存图片
publicstaticintWIDTH=120; publicstaticintHEIGHT=25; publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse) throwsServletException,IOException{ response.setContentType("text/html"); //创建内存图像 BufferedImageimage=newBufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB); //勾勒图像 Graphicsgraphics=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(inti=0;i<8;i++){ intxStart=newRandom().nextInt(WIDTH); intyStart=newRandom().nextInt(HEIGHT); intxEnd=newRandom().nextInt(WIDTH); intyEnd=newRandom().nextInt(HEIGHT); graphics.drawLine(xStart,yStart,xEnd,yEnd); } //写随机数 graphics.setColor(Color.RED); intx=5; for(inti=0;i<4;i++){ graphics.drawString(newRandom().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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