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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