开始路由前，Angular 6调用后台api

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

@Injectable({
  providedIn: 'root'
})
export class ApiService {
  private apiUrl = 'http://example.com/api'; // 后台API的URL

  constructor(private http: HttpClient) { }

  // 发送GET请求
  public get(endpoint: string) {
    return this.http.get(`${this.apiUrl}/${endpoint}`);
  }

  // 发送POST请求
  public post(endpoint: string, data: any) {
    return this.http.post(`${this.apiUrl}/${endpoint}`, data);
  }

  // 其他HTTP请求方法（PUT、DELETE等）可以根据需要添加
}

import { Component } from '@angular/core';
import { ApiService } from './api.service';

@Component({
  selector: 'app-my-component',
  template: `
    <button (click)="getData()">获取数据</button>
    <div>{{ responseData }}</div>
  `
})
export class MyComponent {
  public responseData: any;

  constructor(private apiService: ApiService) { }

  public getData() {
    this.apiService.get('data').subscribe(
      (response) => {
        this.responseData = response;
      },
      (error) => {
        console.error(error);
      }
    );
  }
}