全局ExceptionHandler中的Angular 2重定向

Question

我正在嘗試實現一個將用戶重定向到錯誤頁面的ExceptionHandler。

為此，我需要注入一個路由器對象，如下所示：

@Injectable()
class RedirectExceptionHandler extends ExceptionHandler {

  constructor(private router: Router) {
    super(null, null);
  }

  call(error: any, stackTrace: any = null, reason: any = null) {
    // ...log and redirect to error page
  }
}

但是，當我運行此代碼時，我得到一個異常：

(index):87 Error: EXCEPTION: Error during instantiation of ApplicationRef_! (ApplicationRef -> ApplicationRef_).
    ORIGINAL EXCEPTION: Cannot instantiate cyclic dependency! (ExceptionHandler -> Router -> ApplicationRef)
    ORIGINAL STACKTRACE:
    Error: DI Exception
        at CyclicDependencyError.BaseException [as constructor] (http://localhost:1080/node_modules/@angular/core/src/facade/exceptions.js:17:23)
        at CyclicDependencyError.AbstractProviderError[as constructor] (http://localhost:1080/node_modules/@angular/core/src/di/reflective_exceptions.js:39:16)
        at new CyclicDependencyError(http://localhost:1080/node_modules/@angular/core/src/di/reflective_exceptions.js:102:16)
        at ReflectiveInjector_._new (http://localhost:1080/node_modules/@angular/core/src/di/reflective_injector.js:613:19)
        at ReflectiveInjectorDynamicStrategy.getObjByKeyId (http://localhost:1080/node_modules/@angular/core/src/di/reflective_injector.js:270:50)
        at ReflectiveInjector_._getByKeyDefault (http://localhost:1080/node_modules/@angular/core/src/di/reflective_injector.js:795:38)
        at ReflectiveInjector_._getByKey (http://localhost:1080/node_modules/@angular/core/src/di/reflective_injector.js:767:25)
        at ReflectiveInjector_._getByReflectiveDependency (http://localhost:1080/node_modules/@angular/core/src/di/reflective_injector.js:757:21)
        at ReflectiveInjector_._instantiate (http://localhost:1080/node_modules/@angular/core/src/di/reflective_injector.js:654:36)
        at ReflectiveInjector_._instantiateProvider (http://localhost:1080/node_modules/@angular/core/src/di/reflective_injector.js:626:25)
    Evaluating http://localhost:1080/app/main.js
    Error loading http://localhost:1080/app/main.js

這有解決方案嗎？ 是否可以在調用方法中實例化路由器，從而避免在對象創建期間出現循環依賴？

Answer 1

在已經實例化錯誤處理程序組件之后，注入Angular的注入器並在稍后階段獲取路由器實例：

constructor(private injector:Injector) {
    super(null);
}

ngOnInit() {
    this.router = this.injector.get(Router);
}

所以稍后您可以使用路由器實例：

call(exception:any, stackTrace?:any, reason?:string):void {
    this.router.navigate(...);
}