通过单个请求发送 JSON 和图像。 Angular + Spring Boot

弹簧支撑控制器

@PostMapping(
    value = "/post",
    produces = MediaType.APPLICATION_JSON_VALUE,
    consumes = {MediaType.APPLICATION_JSON_VALUE, MediaType.MULTIPART_FORM_DATA_VALUE}
)
public ResponseEntity<User> handleFileUpload(@RequestParam("user") User user, @RequestPart("file") MultipartFile file) {
    // do something with User and file
    return ResponseEntity.ok().build();
}

角度服务

@Injectable()
export class UploadFileService {

  constructor(private http: HttpClient) { }
  pushFileToStorage(file: File): Observable<HttpEvent<{}>> {
    let formdata: FormData = new FormData();
    formdata.append('file', file);
    formdata.append('user', JSON.stringify(new User('John', 12)))

    const req = new HttpRequest('POST', '/post', formdata, {
      reportProgress: true,
    });

    return this.http.request(req);
  }
}

当我尝试发送请求时，我得到了500 Internal Server Error.

这是一个请求标头

POST /post HTTP/1.1
Host: localhost:4200
Connection: keep-alive
Content-Length: 152881
Accept: application/json, text/plain, */*
Content-Type: multipart/form-data; boundary=----WebKitFormBoundarydaQb5yaWw2xu1V9r
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9

请求负载

------WebKitFormBoundarydaQb5yaWw2xu1V9r
Content-Disposition: form-data; name="file"; filename="Screen Shot 2017-10-24 at 8.49.13 PM.png"
Content-Type: image/png


------WebKitFormBoundarydaQb5yaWw2xu1V9r
Content-Disposition: form-data; name="user"

{"name":"John","age":12}
------WebKitFormBoundarydaQb5yaWw2xu1V9r--

注意：如果在 Spring Rest 控制器中我将参数类型 User 更改为 String 它可以工作。

问题：如何从 Angular 发送请求，以便在 Spring 上我可以获得 User 和 MultipartFile，而不是 String。

Changing

public ResponseEntity<User> handleFileUpload(@RequestParam("user") User user, @RequestPart("file") MultipartFile file)

to

public ResponseEntity<User> handleFileUpload(@RequestPart("user") User user, @RequestPart("file") MultipartFile file)

并将请求更改为类似这样的内容将会起作用：

curl -i -X POST -H "Content-Type: multipart/form-data" \
-F 'user={"name":"John","age":12};type=application/json' \
-F "[email protected] /cdn-cgi/l/email-protection" http://localhost:8080/post

For consumes only MediaType.MULTIPART_FORM_DATA_VALUE是必须的。

要以角度提出上述类型的请求，可以这样做：

const userBlob = new Blob(JSON.stringify(new User('John', 12)),{ type: "application/json"});
formdata.append('user', userBlob);