虽然在正常的html和表单方式下上传效果很好，但是切换到ajax却失败了，并且在调试模式下MultipartFile总是Null。

code below works fine

//html code

//java code

@RequestMapping(value = "/api/upload", consumes = "*/*", method = RequestMethod.POST)

public ResponseEntity upload(@RequestParam(value = "file", required = false) MultipartFile file, MultipartHttpServletRequest request) {

return new ResponseEntity(fileService.upload(file), HttpStatus.OK);

}

以下代码不起作用！

$(document).ready(function () {

$("#btnSubmit").click(function (event) {

event.preventDefault();

var form = $('#fileUploadForm')[0];

var data = new FormData(form);

$.ajax({

type: "POST",

enctype: 'multipart/form-data',

url: "/api/upload",

data: data,

processData: false,

contentType: false,

cache: false,

timeout: 600000,

success: function (data) {

console.log("SUCCESS : ", data);

$("#btnSubmit").prop("disabled", false);

}

});

});

});

有人在这里提供一些线索吗？