help!!!!
<%@   page   contentType= "text/html;   charset=gb2312 "   language= "java "   import= "java.sql.* "   
errorPage= " "   %>  
  <%@   page   import= "java.awt.* "   %>  
  <%@   page   import= "java.io.* "   %>  
  <%@   page   import= "java.awt.image.* "   %>  
  <%@   page   import= "java.awt.geom.* "   %>  
  <%@   page   import= "com.sun.image.codec.jpeg.* "   %>    
  <!DOCTYPE   HTML   PUBLIC    "-//W3C//DTD   HTML   4.01   Transitional//EN "    "http://www.w3.org/TR/html4/loose.dtd ">  
  <html>  
  <head>  
  <meta   http-equiv= "Content-Type "   content= "text/html;   charset=gb2312 ">  
  <title> 无标题文档 </title>  
  </head>    
  <body>  
  <br> 观看旋转的椭圆 
  <form   action= " "   method= "post "   name= "form ">  
        <input   type= "submit "   value= "观看 "   name= "Submit "   >  
  </form>  
  <% 
       String   str=request.getParameter( "submit "); 
       if(str!=null) 
       { 
             response.setContentType( "image/jpeg "); 
 	int   width=260,   height=260; 
 	BufferedImage   image   =   new   BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); 
 	Graphics   g   =   image.getGraphics(); 
 	g.setColor(Color.white); 
 	g.fillRect(0,   0,   width,   height); 
 	Graphics2D   g_2d=(Graphics2D)g; 
 	Ellipse2D   ellipse=new   Ellipse2D.   Double   (20,50,120,50); 
 	g_2d.setColor(Color.blue); 
 	AffineTransform   trans=new   AffineTransform(); 
 	      for(int   i=1;i <=24;i++) 
 	            { 
 		      trans.rotate(15.0*Math.PI/180,75,75); 
 		      g_2d.setTransform(trans); 
 		      g_2d.draw(ellipse); 
 		} 
       g.dispose(); 
       OutputStream   outClient=   response.getOutputStream(); 
       JPEGImageEncoder   encoder=JPEGCodec.createJPEGEncoder(outClient); 
       encoder.encode(image); 
       } 
       %>  
  </body>  
  </html>  
       原封不动的抄的 为什么看不到旋转的椭圆
------解决方案-------------------- <input type= "submit " value= "观看 " name= "Submit " >  
 Submit你是大写的   
 String str=request.getParameter( "submit "); 
 这里你是小写的。   
 改一下就行了