如何使用服务文件中的subscribe向组件返回值？

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

@Injectable({
  providedIn: 'root'
})
export class DataService {
  private dataSubject: BehaviorSubject<string> = new BehaviorSubject<string>('');

  updateData(value: string) {
    this.dataSubject.next(value);
  }

  getData() {
    return this.dataSubject.asObservable();
  }
}

import { Component, OnInit } from '@angular/core';
import { DataService } from 'path-to-data-service';

@Component({
  selector: 'app-my-component',
  template: `
    <div>{{ data }}</div>
  `
})
export class MyComponent implements OnInit {
  data: string;

  constructor(private dataService: DataService) {}

  ngOnInit() {
    this.dataService.getData().subscribe(value => {
      this.data = value;
    });
  }
}