angular4实现发布、订阅功能（基于observable）

import {Injectable} from "@angular/core";import {Subject} from "rxjs/Subject";import {Observable} from "rxjs/Observable";@Injectable()export class HisCurveAddService {    private _selectedPoint: Subject<any> = new Subject<any>();    public constructor() {    }  public setSelectedPoint(selectedPointsIfo: any): void {        this._selectedPoint.next(selectedPointsIfo);    }    public currentSelectedPoint(): Observable<any> {        return this._selectedPoint.asObservable();    }}使用//发布
this._hisCurveAddService.setSelectedPoint(arg）//订阅
this._hisCurveAddService.currentSelectedPoint().subscribe((value: any)=>{console.log(value)});