springmvc的MultipartFile参数如果不上传文件报错的问题

 1 @RequestMapping(value = "/updateInformation",method = RequestMethod.POST)
 2     @ResponseBody
 3     public Boolean updateInformation(Commodity commodity, HttpServletRequest request)throws Exception {
 4         MultipartFile file = null;
 5         boolean isMultipart = ServletFileUpload.isMultipartContent(request);
 6         if (isMultipart){
 7             MultipartHttpServletRequest multipartRequest = WebUtils.getNativeRequest(request, MultipartHttpServletRequest.class);
 8             file = multipartRequest.getFile("file");
 9         }
10       }

commodity是pojo类
出错是的代码是这样的

  @RequestMapping(value = "/updateInformation",method = RequestMethod.POST)
    @ResponseBody
    public Boolean updateInformation(@RequestParam("file") MultipartFile file,Commodity commodity, HttpServletRequest request)throws Exception {
       }

　　后台报错为; Required request part 'file' is not present

　　页面报错为：  Request method 'GET' not supported