如何使用angular 7从后台应用程序获取字符串响应

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

@Injectable({
  providedIn: 'root'
})
export class BackendService {

  constructor(private http: HttpClient) { }

  // 在这里编写与后台应用程序通信的方法
}

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

@Injectable({
  providedIn: 'root'
})
export class BackendService {

  constructor(private http: HttpClient) { }

  getStringResponseFromBackend(): Observable<string> {
    return this.http.get<string>('http://your-backend-url/api/endpoint');
  }
}

import { Component } from '@angular/core';
import { BackendService } from './backend.service';

@Component({
  selector: 'app-your-component',
  template: `
    <button (click)="getResponse()">Get Response</button>
    <div>{{ response }}</div>
  `
})
export class YourComponent {

  response: string;

  constructor(private backendService: BackendService) { }

  getResponse(): void {
    this.backendService.getStringResponseFromBackend().subscribe(
      response => this.response = response,
      error => console.error(error)
    );
  }
}