以下代码经测试成功, 直接复制到JSP中即可以运行 
<%@ page import="java.awt.*" %> <%@ page import="java.awt.image.*" %> <%@ page import="com.sun.image.codec.jpeg.*" %> <%@ page import="java.util.*" %> 
 <%   //test by liboy 
  int width=400;   int height= 400; 
  BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);      Graphics g = image.getGraphics();   //Graphics2d g2d = image.createGraphics(); 
   g.setColor(Color.white);   g.fillRect(0, 0, width, height);   g.setColor(Color.black);   g.drawRect(0,0,width-1,height-1);   // Create random polygon   Polygon poly = new Polygon();   Random random = new Random();   for (int i=0; i<5; i++) {   poly.addPoint(random.nextInt(width), random.nextInt(height));   }   // Fill polygon   g.setColor(Color.cyan);   g.fillPolygon(poly);   // Dispose context   g.dispose(); 
         response.reset();         response.setContentType("image/jpeg"); 
  ServletOutputStream sos = response.getOutputStream();   JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(sos);   encoder.encode(image); 
%> 
OICQ: 86804  
 
  |