angular6或7:如何在'@angular/common/http'中导入RequestOptions和ResponseContentType

angular 6 or 7: How to import RequestOptions and ResponseContentType in '@angular/common/http'

我已将 angular 4 代码迁移到 angular 6,我想知道如何在 angular 6 或 7 中导入以下代码?

import { RequestOptions, ResponseContentType } from '@angular/common/http';

从这边过去...

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

 let headers = new HttpHeaders({
    'Content-Type': 'application/json'
 });
 let options = {
    headers: headers
 }

 this.http.post(URL, param, options)
    .subscribe(data => {
         console.log(data);
 });



 // For pass blob in API 

 return this.http.get(url, { headers: new HttpHeaders({
   'Authorization': '{data}',
   'Content-Type': 'application/json',
 }), responseType: 'blob'}).pipe (
 tap (
     // Log the result or error
     data => console.log('You received data'),
     error => console.log(error)
  )
);