angular 基本依赖注入

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

@Injectable()
export class ProductServiceService {

  constructor() { }

  getProduct(): Product {
    return new Product(1, "iPhone7");
  }

}

export class Product {
  constructor(
    public id: number,
    public title: string
  ) { }
}

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


import { AppComponent } from './app.component';
import { Product1Component } from './product1/product1.component';
import { ProductServiceService } from './shared/product-service.service';


@NgModule({
  declarations: [
    AppComponent,
    Product1Component
  ],
  imports: [
    BrowserModule
  ],
  providers: [ProductServiceService],
  bootstrap: [AppComponent]
})
export class AppModule { }

import { Component, OnInit } from '@angular/core';
import { ProductServiceService, Product } from '../shared/product-service.service';

@Component({
  selector: 'app-product1',
  templateUrl: './product1.component.html',
  styleUrls: ['./product1.component.css']
})
export class Product1Component implements OnInit {

  product: Product;

  constructor(private productService: ProductServiceService) { }

  ngOnInit() {
    this.product = this.productService.getProduct();
  }

}

<p>
  商品Id:{{product.id}}
</p>
<p>
    商品描述:{{product.title}}
  </p>