使用observable获取HTTP响应

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

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})

export class AppComponent implements OnInit{

  formData = {
    first_name:"",
    last_name:"",
    middle_name:"",
    mobile_number:"",
    email_address:"",
    password:"",
    confirm_password:""
  };  

  constructor(private httpClient:HttpClient) {

  }

  ngOnInit() {
    console.log(this.httpClient.get("http://localhost:8000"));
    // how to use this returned Observable to get the actual response.
  }

  submittedDetails(){
      console.log('FirstName: ' + this.formData.first_name);
      console.log('LastName: ' + this.formData.last_name);
      console.log('MiddleName: ' + this.formData.middle_name);
      console.log('Email Address: ' + this.formData.email_address);
      console.log('MobileNumber: ' + this.formData.mobile_number);
      console.log('Password: ' + this.formData.password);
      console.log('Confirm Password: ' + this.formData.confirm_password);   
  }
}

• ngInit() 纯粹是为了学习。

• 我正在使用 角度6

困难/问题:

我可以向我的后端代码和内部代码发出请求 ngInit() Observable . 现在,如何使用它来查看收到的实际响应?

我很抱歉,如果我理解这里有什么错误(在角度方面)。