解决layui上传文件提示上传异常,实际文件已经上传成功的问题

@ResponseBody
@RequestMapping("/web/upload")
public JSON  uploadSourceData(@RequestParam(value="file") MultipartFile file ){
String filePath = “”;
String fileName = filePath+System.currentTimeMillis()+"_"+file.getOriginalFilename(); //上传后的文件名  原始文件名加上时间戳
FileOutputStream out;
JSON  resObj = new JSON ();
resObj.put("msg", "ok");
try {
out = new FileOutputStream(new File(fileName));
IOUtils.copy(file.getInputStream(), out);
out.close();
} catch (Exception e) {
// TODO Auto-generated catch block
resObj.put("msg", "error");
e.printStackTrace();
}
return resObj;
}