Angular2  NgModule 模块详解

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

/* App Root */
import { AppComponent } from './app.component';

/* Feature Modules */
import { ContactModule } from './contact/contact.module';
import { CoreModule } from './core/core.module';
import { routing } from './app.routing';
import { Title } from '@angular/platform-browser';
@NgModule({
 imports: [
  BrowserModule,
  ContactModule,
  /*
    CoreModule,
  */
  CoreModule.forRoot({ userName: 'Miss Marple' }),
  routing
 ],
 declarations: [AppComponent],//声明当前模块需要的指定 组件信息
 exports:[],
 providers: [Title],
 bootstrap: [AppComponent]
})
export class AppModule { }

import { NgModule }      from '@angular/core';
import { SharedModule }    from '../shared/shared.module';

import { ContactComponent }  from './contact.component';
import { ContactService }   from './contact.service';
import { routing }      from './contact.routing';
import{GuozhiqiModule}from '../directives/guozhiqi.module';
import{AppModule}from '../app.module';
@NgModule({
 imports:   [ SharedModule, routing,GuozhiqiModule,AppModule ],// 导入模块
 declarations: [ ContactComponent ],//声明 指令 
 providers:  [ ContactService ]//服务提供者 在当前模块提供者中注册当前模块需要的服务
})
export class ContactModule { }

constructor (@Optional() @SkipSelf() parentModule: CoreModule) {
  if (parentModule) {
   throw new Error(
    'CoreModule is already loaded. Import it in the AppModule only');
  }
 }