如何在Angular中重新执行订阅的Observable

import { Component, OnInit } from '@angular/core';
import { Subject } from 'rxjs';
import { switchMap } from 'rxjs/operators';

@Component({
  selector: 'app-example',
  templateUrl: './example.component.html',
  styleUrls: ['./example.component.css']
})
export class ExampleComponent implements OnInit {
  private refreshSubject = new Subject<void>();

  constructor() {}

  ngOnInit(): void {
    this.refreshSubject.pipe(
      switchMap(() => this.getData())
    ).subscribe(data => {
      console.log(data);
    });
  }

  refreshData(): void {
    this.refreshSubject.next();
  }

  private getData(): Observable<any> {
    // 模拟获取数据的Observable
    return of('New Data').pipe(delay(1000));
  }
}

import { Component, OnInit, OnDestroy } from '@angular/core';
import { Subject } from 'rxjs';
import { takeUntil } from 'rxjs/operators';

@Component({
  selector: 'app-example',
  templateUrl: './example.component.html',
  styleUrls: ['./example.component.css']
})
export class ExampleComponent implements OnInit, OnDestroy {
  private destroy$ = new Subject<void>();

  constructor() {}

  ngOnInit(): void {
    this.subscribeToData();
  }

  ngOnDestroy(): void {
    this.destroy$.next();
    this.destroy$.complete();
  }

  refreshData(): void {
    this.unsubscribe();
    this.subscribeToData();
  }

  private subscribeToData(): void {
    this.getData().pipe(
      takeUntil(this.destroy$)
    ).subscribe(data => {
      console.log(data);
    });
  }

  private unsubscribe(): void {
    this.destroy$.next();
    this.destroy$.complete();
    this.destroy$ = new Subject<void>();
  }

  private getData(): Observable<any> {
    // 模拟获取数据的Observable
    return of('New Data').pipe(delay(1000));
  }
}

import { Component, OnInit } from '@angular/core';
import { of, timer } from 'rxjs';
import { repeatWhen, take } from 'rxjs/operators';

@Component({
  selector: 'app-example',
  templateUrl: './example.component.html',
  styleUrls: ['./example.component.css']
})
export class ExampleComponent implements OnInit {
  constructor() {}

  ngOnInit(): void {
    this.getData().pipe(
      repeatWhen(() => timer(0)),
      take(3) // 控制重复次数
    ).subscribe(data => {
      console.log(data);
    });
  }

  private getData(): Observable<any> {
    // 模拟获取数据的Observable
    return of('New Data').pipe(delay(1000));
  }
}