ajax上传文件报400错误

Question

1、ajax

jQuery.ajax({

url: contextUrl + "/accidentAttachment/saveAccidentAttachment",
type:'post',
data: formData,
contentType: false,
processData: false,
error: function (XMLHttpRequest, status) {
    bootbox.alert('上传文件失败！');
},

2、html

选择文件

<input type="file" name="scenePhotosEl" id="scenePhotosEl"
       accept="image/png, image/jpeg, image/gif, image/jpg"
       @change="uploadPic()">

3、后端代码

@RequestMapping(value = "/saveAccidentAttachment", method = RequestMethod.POST)
@ResponseBody
public ResponseData saveAccidentAttachment(@RequestParam("file") MultipartFile multipartFile, @RequestParam String bizType) {...

4、报错信息

Request URL: http://localhost:8080/accidentAttachment/saveAccidentAttachment
Request Method: POST
Status Code: 400 Bad Request
Remote Address: [::1]:8080
Referrer Policy: no-referrer-when-downgrade

Accept: */*
Accept-Encoding: gzip, deflate, br
Accept-Language: zh-CN,zh;q=0.9
Cache-Control: no-cache
Connection: keep-alive
Content-Length: 153966
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryk5RsQTH9ae4jvG4k
Cookie: Webstorm-d6a483d9=0efba8f4-fa39-4a6b-9ac4-4ea22de7ab23; sso.jd.com=TEST.882a88797c4d4771b80d034bc8c327d7; JSESSIONID=ED7C20A5A21F5714B328F97DFD0DFDDC
Host: localhost:8080
Origin: http://localhost:8080
Pragma: no-cache
Referer: http://localhost:8080/accident/detail?id=159&type=edit&_time=1574848776183
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.103 Safari/537.36
X-Requested-With: XMLHttpRequest