获取网站资源 getResourceAsStream

     获取网站资源(重点)
 public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
         // 获取网站对象
         ServletContext context = this.getServletContext();
         // 获取网站中的静态资源
         InputStream in = context.getResourceAsStream("/123.bmp");
         // 获取输出流
         FileOutputStream out = new FileOutputStream(new File("d:/123.bmp"));
         // 边读 边写
         byte[] bs  = new byte[1024];
         int len = 0;
         while((len = in.read(bs)) != -1){
             out.write(bs, 0, len);
             out.flush();
         }
         // 释放资源
         in.close();
         out.close();
     }