实现Ajax的Submit上传文件时提示用户

@RequestMapping(value="scoreFileUpload",produces = "text/html; charset=utf-8") 
 @ResponseBody 
 public String upload(HttpSession session,@RequestParam("file1") MultipartFile file,@RequestParam("paperId") String paperId,HttpServletRequest request) { 
 //获取登录人员的id 
 Integer userId = (Integer) session.getAttribute(BaseConstant.SESSION_UERID_KEY); 
 JSONObject json = new JSONObject(); 
 if (request instanceof MultipartHttpServletRequest) { 
 //获取上传文件的文件名 
 String fileName = file.getOriginalFilename(); 
 String subfix = FileUtils.getFileExtend(fileName); 
 } 
return ""; 
 }

$('#fileForm').submit(function() { 
 var _businessDetailId = $("#businessDetailId").val(); 
 var _paperId = $("#paperId").val(); 
 var url = "scoreFileUpload?paperId="+_paperId+"&businessDetailId="+_businessDetailId; 
 var optionss = { 
 dataType:"text/html", 
 type:'post', 
 url: url, 
 // beforeSubmit:showRequest, 
 complete:showResponse, 
 clearForm:false, 
 timeout: 3000000 
 }; 
 //提交表单 
 $(this).ajaxSubmit(optionss); 
 // !!! Important !!! 
 // 为了防止普通浏览器进行表单提交和产生页面导航（防止页面刷新？）返回false 
 return false; 
 });<pre name="code" class="javascript">function showResponse(data) { 
 data = JSON.parse(data.responseText); 
 if(data.type != null) { 
 } 
}