关于图片下载按钮

图片下载看起来说简单也不简单，曾经在一个j2ee论坛上求救过这个问题，有个"java高手"告诉我做个超链接，当时我就有点晕了，下面给出一个我做的例子。

给图片一个连接:)
       onclick="javascript:window.location.href='<%=path%>/servlet/download?fileName=图片相对地址&&imgName=另存为时图片名称;" 

Servlet  Download .java
    public class download extends HttpServlet {

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  try{
       doPost(request,response);
    }
    catch(Exception e){}
  
 }

 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  try {  
      String filename = request.getParameter("fileName");   
      String name=request.getParameter("imgName")+".jpg";
      if(filename!=null)
      {   
      //String filename2 =filename.substring(filename.lastIndexOf("/"));
    
      String rootpath = getServletContext().getRealPath("/"); 
     
      String filepath = rootpath + filename.substring(1);
      FileInputStream fis = new FileInputStream(filepath);
      ServletOutputStream fout = response.getOutputStream();
      response.setContentType("image/jpeg");     
      response.setHeader("Content-disposition","attachment;filename=/""+ name + "/"");  
      int byteRead;   
      while((byteRead = fis.read())!=-1){
         fout.write(byteRead);   
      }
     fis.close();
     fout.close();
     }
      }
      catch (Exception e) {
       e.printStackTrace();
      }  
    return;  

 }

}