基本步骤

1.先在app.module.ts中引入 import { HttpClientModule } from '@angular/common/http'

2.然后在 imports: [ BrowserModule, AppRoutingModule, FormsModule, HttpClientModule],中加入 HttpClientModule

3.再在primordial.component.ts文件中引入import { HttpClient } from '@angular/common/http';

4.接着在这个文件中constructor中引入：constructor(public http:HttpClient) { }

5.然后进行使用

代码演示

primordial.component.ts文件中先进行引入

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