Angular2“服务"如何将一项服务注入另一项(单例)?

并且看到他对以下内容发表评论: http://twofuckingdevelopers.com/2015/04/angular- 2单服务/使用Angular 2的DI注入的所有东西都已经是Singleton.不需要这种服务"我去测试了，现在发现的内容都回答了我的问题，并使我对angular2中的DI主题更加困惑.请参见以下代码: team.ts import {BaseCollection, BaseModel} from "./base";import {PlayerCollection} from './player';import {Injectable, Inject} from "angular2/angular2";@Injectable()export class TeamCollection extends BaseCollection { playerCollection: PlayerCollection; constructor(@Inject(PlayerCollection) playerCollection: PlayerCollection) { super(); this.playerCollection = playerCollection; } create(data: Object): TeamModel { return new TeamModel(data); }} player.ts import {BaseCollection, BaseModel} from "./base";import {Injectable} from "angular2/angular2";@Injectable()export class PlayerCollection extends BaseCollection { create(data: Object): PlayerModel { return new PlayerModel(data); }} team.spec.ts /// <reference path="../../typings.d.ts" />//VERY IMPORTANT TO ALWAYS LOAD THESEimport 'zone.js';import 'reflect-metadata';import 'es6-shim';import {TeamModel, TeamCollection} from "../../app/model/team";import {PlayerCollection} from "../../app/model/player";import {Inject, Injector} from "angular2/angular2";describe('TeamCollection', () => { var teamCollection: TeamCollection; var playerCollection: PlayerCollection; beforeEach(() => { var injector = Injector.resolveAndCreate([ TeamCollection, PlayerCollection ]); teamCollection = injector.get(TeamCollection); var injectorT = Injector.resolveAndCreate([ PlayerCollection ]); playerCollection = injector.get(PlayerCollection); }); it('should have a singleton PlayerCollection shared between all classes within the application', () => { console.log(teamCollection.playerCollection.uuId); console.log(playerCollection.uuId); });});只要是创建它们的相同注入器(var injector)，它们就共享相同的uuID.虽然当我使用第二个注入器(var injectorT)时，UUID是不同的，这意味着将创建playerCollection的新实例.现在我的问题是.如果我使用组件提供程序语法:@Component({ selector: 'app', providers: [TeamCollection]})@Component({ selector: 'player-list', providers: [PlayerCollection]})会共享同一个玩家集合还是会创建一个新实例?只要通过bootstrap(.., [ServiceA,ServiceB])方法创建它们即可.感谢pascal precht http://blog .thoughtram.io/angular/2015/09/17/resolve-service-dependencies-in-angular-2.html How would I go about injecting one service into another? Let's for example say I have a Collection that requires another Collection (TeamCollection => PlayerCollection). Currently I just create two separate Collections and use something like:import {PlayerCollection} from "<<folder>>/player";But this requires me to write my own singleton getInstance code within Typescript for each and every service that I want to be a singleton instance.What is the correct way to do this? I want to have both singletons within my Components and be able to @Inject one service into another using the constructor syntax, without creating a new instance of the singletons.class TeamCollection { constructor(@Inject(PlayerCollection): PlayerCollection) {}} 解决方案 So after re-reading this excellent post by Pascal Precht: http://blog.thoughtram.io/angular/2015/05/18/dependency-injection-in-angular-2.htmlAnd seeing him comment on: http://twofuckingdevelopers.com/2015/04/angular-2-singleton-service/"Everything injected using Angular 2’s DI is already a Singleton. No need for such a service"I went testing, and what I now found has both answered my question and made me even more confused about the topic of DI in angular2.See the following code:team.tsimport {BaseCollection, BaseModel} from "./base";import {PlayerCollection} from './player';import {Injectable, Inject} from "angular2/angular2";@Injectable()export class TeamCollection extends BaseCollection { playerCollection: PlayerCollection; constructor(@Inject(PlayerCollection) playerCollection: PlayerCollection) { super(); this.playerCollection = playerCollection; } create(data: Object): TeamModel { return new TeamModel(data); }}player.tsimport {BaseCollection, BaseModel} from "./base";import {Injectable} from "angular2/angular2";@Injectable()export class PlayerCollection extends BaseCollection { create(data: Object): PlayerModel { return new PlayerModel(data); }}team.spec.ts/// <reference path="../../typings.d.ts" />//VERY IMPORTANT TO ALWAYS LOAD THESEimport 'zone.js';import 'reflect-metadata';import 'es6-shim';import {TeamModel, TeamCollection} from "../../app/model/team";import {PlayerCollection} from "../../app/model/player";import {Inject, Injector} from "angular2/angular2";describe('TeamCollection', () => { var teamCollection: TeamCollection; var playerCollection: PlayerCollection; beforeEach(() => { var injector = Injector.resolveAndCreate([ TeamCollection, PlayerCollection ]); teamCollection = injector.get(TeamCollection); var injectorT = Injector.resolveAndCreate([ PlayerCollection ]); playerCollection = injector.get(PlayerCollection); }); it('should have a singleton PlayerCollection shared between all classes within the application', () => { console.log(teamCollection.playerCollection.uuId); console.log(playerCollection.uuId); });});As long as it was the same Injector (var injector) that created both they share the same uuID Though when I use a second injector (var injectorT) the UUIDs are different meaning a new instance is created of the playerCollection.Now my question would be. If I use the component providers syntax:@Component({ selector: 'app', providers: [TeamCollection]})@Component({ selector: 'player-list', providers: [PlayerCollection]})Would both share the same player collection or would both create a new instance?Edit:They do as long as they are created through the bootstrap(.., [ServiceA,ServiceB]) method.Thanks to pascal precht http://blog.thoughtram.io/angular/2015/09/17/resolve-service-dependencies-in-angular-2.html 这篇关于Angular2“服务"如何将一项服务注入另一项(单例)?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！