Angular2:从后端下载我得到的xls文件

import { HttpClient } from '@angular/common/http';

constructor(private http: HttpClient) { }

downloadFile() {
  this.http.get('后端下载xls文件的URL', { responseType: 'blob' })
    .subscribe((data: Blob) => {
      const downloadUrl = window.URL.createObjectURL(data);
      const link = document.createElement('a');
      link.href = downloadUrl;
      link.download = '文件名.xls';
      link.click();
      window.URL.revokeObjectURL(downloadUrl);
    });
}

<button (click)="downloadFile()">下载xls文件</button>