ImageServlet类

public class ImageServlet extends HttpServlet{

@Override

public void doGet(HttpServletRequest request,HttpServletResponse response)

throws IOException,ServletException{

//响应的内容类型

response.setContentType("image/jpeg");

//产生图像画片。图像宽度是300，高度40。

BufferedImage img = newBufferedImage(200,20,BufferedImage.TYPE_INT_RGB);

//获得画笔

Graphics g = img.getGraphics();

//设置画笔的颜色

g.setColor(new Color(166,255,99));

//绘制实心矩形

g.fillRect(0, 0, 200, 20);

//重新设置颜色

g.setColor(Color.black);

StringBuffer sb = new StringBuffer();

for(int i=0;i<4;i++){

//产生0-9的整数

int number = (int)(Math.random()*10);

sb.append(number+"  ");

}

g.drawString(sb.toString(), 5, 5);

//获得向客户端发送的输出流

ServletOutputStream out = response.getOutputStream();

//发送图片数据

JPEGImageEncoder jpg =JPEGCodec.createJPEGEncoder(out);

jpg.encode(img);

}

}