Angular 2-如何以特定顺序实例化组件中的多个服务？

import { Component } from '@angular/core';
import { ServiceA } from './service-a';
import { ServiceB } from './service-b';

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  styleUrls: ['./my-component.component.css'],
  providers: [ServiceA, ServiceB] // 声明需要注入的服务
})
export class MyComponent {
  constructor(private serviceA: ServiceA, private serviceB: ServiceB) {
    // 在构造函数中注入服务
  }
}

import { Injectable } from '@angular/core';

@Injectable()
export class ServiceA {
  constructor() {
    console.log('ServiceA 实例化');
  }
}

@Injectable()
export class ServiceB {
  constructor() {
    console.log('ServiceB 实例化');
  }
}

<h1>My Component</h1>
<p>ServiceA: {{ serviceA }}</p>
<p>ServiceB: {{ serviceB }}</p>