我无法使用Angular2将Excell发送到服务器

Question

我正在尝试使用Angular2将Excell发送到SpringBoot，但是出现错误。

HTMl：

      <form #fileLoad="ngForm" (ngSubmit)="addExcell(fileLoad)">
          <input type="file" id="file" name="file" class="form-control" [(ngModel)]="ngNameFile" accept=".xlsx">
          <button class="btn btn-sm btn-outline btn-block">Add</button>
      </form>

Angular2

  addExcell(fileLoad) {
     console.log('fileLoad' , fileLoad);
     const url = 'http://localhost:8080/ml/insert';
     this.service.sendFile(url, 
       JSON.parse(fileLoad.form.controls.file)).subscribe(
          data => {
            console.log('data');
            }
        );
  }

Service:
 sendFile(url, File) {
    return this.http.post(url, File, { responseType: 'blob' });
  }

SpringBoot：

    @ApiOperation("Upload XLSX file")
    @RequestMapping(method = RequestMethod.POST, value = "/insert", produces 
    = MediaType.APPLICATION_JSON_VALUE)
    public String insert(@RequestBody MultipartFile multipart) {

        System.out.println("file" + multipart);
        return "good";

    }

错误：

ERROR SyntaxError: Unexpected token o in JSON at position 1
    at JSON.parse (<anonymous>)
    at ManualLoadComponent.addExcell (manual-load.component.ts:24)
    at Object.eval [as handleEvent] (ManualLoadComponent.html:22)
    at handleEvent (core.js:13589)
    at callWithDebugContext (core.js:15098)
    at Object.debugHandleEvent [as handleEvent] (core.js:14685)
    at dispatchEvent (core.js:10004)
    at eval (core.js:12343)
    at SafeSubscriber.schedulerFn [as _next] (core.js:4354)
    at SafeSubscriber.__tryOrUnsub (Subscriber.js:243)

在我收到应该发送A JSON的错误之前，我先做JsonParse（fileLoad.form.controls.file）），现在我在Json中得到了错误令牌...