我的问题是，我可以用postman（spring boot）上传文件。服务可以工作，但是当我用angular上传文件时，我得到了一个错误。（15不支持媒体类型，内容类型'application/json'不支持）
Spring*

@PostMapping(value = "/upload", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
    public ResponseEntity<HttpStatus> saveProfil(@RequestParam("file") MultipartFile file)

**棱角分明的

const httpOptions = {
    headers: new HttpHeaders().set('Content-Type','multipart/form-data')

     }
    export class ApiService {

      constructor(private httpClient: HttpClient) { }

      postFile(path: string, body: any): Observable<any> {
        return this.httpClient.post(path, body, httpOptions).pipe(catchError(this.formatError));

      }

    }

 onSubmit(event) {

    const file = event.target.files[0];
      this.fileUpload = file;

    const formData:FormData= new FormData();
    formData.append('file',this.fileUpload);

    this.uploadService.saveProfile(formData).subscribe(res => {.....});

}

 saveProfile(formData: FormData): Observable<any> {
    return this.apiService.postFile(apiHost + '/Profil', formData);
  }