upload(file) {
    const req = new HttpRequest('POST', this.urlUpload, file, {
      headers: new HttpHeaders({'Content-Type':'multipart/form-data'}),
      reportProgress: true
    });
    return this.http.request(req);
  }

download() {
    this.downloader.download().subscribe(event => {
      if (event.type === HttpEventType.DownloadProgress) {
      } else if (event instanceof HttpResponse) {
        this.upload(event.body);
      }
    });
  }

  upload(file) {
     this.downloader.upload(file).subscribe( event => {
        if (event.type === HttpEventType.UploadProgress) {
        } else if (event instanceof HttpResponse) {
          console.log('File is completly uploaded!');
        }
      });
  }

@PostMapping("/uploadFile")
    public UploadFileResponse uploadFile(@RequestParam("file") MultipartFile file) {
        return ...;
    }