code: @Override
      protected final void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
          support.bindServer(request, response);
      }
docs: 重写servlet中的get方法，用于处理微信服务器绑定，置为final方法，用户已经无需重写这个方法啦
  
  @param request  http请求对象
  @param response http响应对象
  @throws ServletException servlet异常
  @throws IOException      IO异常