angular-docs-cn/aio/content/examples/providers/src/app/app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';

import { AppComponent } from './app.component';
import { UserService } from './user.service';

@NgModule({
  imports:      [ BrowserModule ],
  providers:    [ UserService ],
  declarations: [ AppComponent ],
  bootstrap:    [ AppComponent ]
})
export class AppModule { }