Implement Ajax Submit to prompt the user when uploading files

@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) { 
  } 
}