https://www.jianshu.com/p/8c8f78eb2740

后端代码

• 其中 UserDto 为接收 json 数据的对象
• 注解为 @RequestPart，用 @RequestParam 接收不到 json 数据

@PostMapping(value = "/uploadFileAndJson")
public void uploadFileAndJson(
                                  @RequestPart("file") MultipartFile file, 
                                  @RequestPart("userDto") UserDto userDto) {
        // 业务代码
}

前端请求

• 这里使用 idea 的 http client

POST http://localhost:8080/uploadFileAndJson
Content-Type: multipart/form-data; boundary=WebAppBoundary

--WebAppBoundary--
Content-Disposition: form-data; name="userDto";
Content-Type: application/json

{"username":"admin", "password":"123456"}

--WebAppBoundary
Content-Disposition: form-data; name="file"; filename="fileUpload.json"

< D:\Documents\Desktop\test.txt


--WebAppBoundary