在Angular 4中查找公共服务的位置

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

@Component({
  selector: 'app-my-component',
  template: '<p>{{ myService.getData() }}</p>',
})
export class MyComponent {
  constructor(private myService: MyService) { }
}

import { NgModule } from '@angular/core';
import { MyService } from './my.service';

@NgModule({
  providers: [MyService],
})
export class MyModule { }

import { Component, Inject } from '@angular/core';
import { MyService } from './my.service';

@Component({
  selector: 'app-my-component',
  template: '<p>{{ myService.getData() }}</p>',
})
export class MyComponent {
  constructor(@Inject(MyService) private myService: MyService) { }
}