如何使用canActivate()来阻止对某些路由的访问？

// auth.guard.ts
import { Injectable } from '@angular/core';
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot, UrlTree, Router } from '@angular/router';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class AuthGuard implements CanActivate {

  constructor(private router: Router) {}

  canActivate(
    next: ActivatedRouteSnapshot,
    state: RouterStateSnapshot): Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree {
    
    // 在这里编写逻辑判断，例如检查用户是否已登录
    const isLoggedIn = true; // 假设用户已登录

    if (isLoggedIn) {
      return true; // 允许访问该路由
    } else {
      // 如果用户未登录，则重定向到登录页面
      this.router.navigate(['/login']);
      return false; // 阻止访问该路由
    }
  }
}

// app-routing.module.ts
import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
import { HomeComponent } from './home/home.component';
import { ProfileComponent } from './profile/profile.component';
import { AuthGuard } from './auth.guard';

const routes: Routes = [
  { path: '', component: HomeComponent },
  { path: 'profile', component: ProfileComponent, canActivate: [AuthGuard] }
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }