31 encapsulates a network service request

① create a service class

　　@Injectable()

　　Service class defined in the method, the data

　　sendRequest ( myUrl : string ) {

　　　　return this.http.get( myUrl ).map(  (response : Response) => response.json()  )

　　}

② to the designated service provider

　　providers: [MyHttpService] module assembly defines a scope

③ call service

　　import { }

　　this.myHttpService.sendRequset ( 'address request') .subscribe ((result: any) => {console.log (reuslt)})