使用Angular8的路由守卫功能报错，具体如下：

  1. core.js:6014 ERROR Error: Uncaught (in promise): NullInjectorError: StaticInjectorError(AppModule)[LoginGuard]: 
  2.   StaticInjectorError(Platform: core)[LoginGuard]: 
  3.     NullInjectorError: No provider for LoginGuard!
  4. NullInjectorError: StaticInjectorError(AppModule)[LoginGuard]: 
  5.   StaticInjectorError(Platform: core)[LoginGuard]: 
  6.     NullInjectorError: No provider for LoginGuard!
  7.     at NullInjector.get (core.js:855)
  8.     at resolveToken (core.js:17514)
  9.     at tryResolveToken (core.js:17440)
  10.     at StaticInjector.get (core.js:17266)
  11.     at resolveToken (core.js:17514)
  12.     at tryResolveToken (core.js:17440)
  13.     at StaticInjector.get (core.js:17266)
  14.     at resolveNgModuleDep (core.js:30393)
  15.     at NgModuleRef_.get (core.js:31578)
  16.     at resolveNgModuleDep (core.js:30393)
  17.     at resolvePromise (zone-evergreen.js:797)
  18.     at resolvePromise (zone-evergreen.js:754)
  19.     at zone-evergreen.js:858
  20.     at ZoneDelegate.invokeTask (zone-evergreen.js:391)
  21.     at Object.onInvokeTask (core.js:39680)
  22.     at ZoneDelegate.invokeTask (zone-evergreen.js:390)
  23.     at Zone.runTask (zone-evergreen.js:168)
  24.     at drainMicroTaskQueue (zone-evergreen.js:559)

admin-routing.module 具体代码 ：

  1. import { NgModule } from '@angular/core';
  2. import { Routes, RouterModule } from '@angular/router';
  3. import { IndexComponent } from '../admin/index/index.component';
  4. import { AdminComponent } from './admin.component';
  5. import { LoginGuard } from '../common-share/guard/login.guard';
  7. const routes: Routes = [
  8.    {
  9.     path: '',
  10.     component: AdminComponent,
  11.     children: [
  12.       {
  13.         path: '',
  14.         redirectTo: 'index',
  15.         pathMatch: 'full'
  16.       },
  17.       {
  18.         path: 'index',
  19.         component: IndexComponent,
  20.         canActivate: [LoginGuard]
  21.       },
  22.     ]
  23.   }
  25. ];
  27. @NgModule({
  28.   imports: [RouterModule.forChild(routes)],
  29.   exports: [RouterModule],
  30. })
  31. export class AdminRoutingModule { }

路由守卫代码：

  1. import {ActivatedRoute, CanActivate, Router} from '@angular/router';
  2. import { AuthService } from '../api/auth/auth.service';
  3. import { Injectable } from '@angular/core';
  4. /**
  5.  * 检查登录
  6.  */
  7. @Injectable()
  8. export class LoginGuard implements CanActivate{
  9.     constructor(private auth: AuthService,private router: Router, private route: ActivatedRoute) {
  10.     }
  11.     canActivate(){
  12.         //检查登录
  13.       if(!this.auth.checkHasLogin()){
  14.             this.router.navigate(['/login'], {
  15.                 relativeTo: this.route
  16.             });
  17.       };
  18.       return true;
  19.     }
  20. }

具体是说我这个LoginGuard没有注入，然后找不到这个守卫

网上解决办法：
  • 导入HttpClientModule import { HttpClientModule } from '@angular/common/http';

检查发现我已经导入了，所以不可能是这个问题

后面检查才发现是，我确实没有注入，我没有在admin-routing.module 里面把LoginGuard加入providers里面，导致找不到。

具体解决办法,在admin-routing.module providers里面加入LoginGuard
  1. @NgModule({
  2.   imports: [RouterModule.forChild(routes)],
  3.   exports: [RouterModule],
  4.   providers: [LoginGuard]
  5. })