如何让Angular 2 CLI ng通过子目录提供服务

npm install -g @angular/cli

mkdir subdirectory

touch subdirectory/my-service.ts

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

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

  // 在这里编写你的服务逻辑
  // ...
}

import { MyService } from './subdirectory/my-service';

@NgModule({
  // ...
  providers: [MyService],
  // ...
})
export class AppModule { }

import { Component } from '@angular/core';
import { MyService } from './subdirectory/my-service';

@Component({
  selector: 'app-root',
  template: `
    <h1>{{ title }}</h1>
  `
})
export class AppComponent {
  title = 'My App';

  constructor(private myService: MyService) { }
}