从文档中添加代码,

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

接着,

http.request(req).subscribe(event => {
  // Via this API,you get access to the raw event stream.
  // Look for upload progress events.
  if (event.type === HttpEventType.UploadProgress) {
    // This is an upload progress event. Compute and show the % done:
    const percentDone = Math.round(100 * event.loaded / event.total);
    console.log(`File is ${percentDone}% uploaded.`);
  } else if (event instanceof HttpResponse) {
    console.log('File is completely uploaded!');
  }
});

编辑
由于OP希望将它与angular2一起使用,因此应该使用本机JavaScript XHR包装为此answer中提到的Observable