使用一个类来存储注射器 此类将容纳模块的注射器。一旦组件或服务需要获得服务依赖项，它将设置一次并检索。

app-injector.service.ts

import { Injector } from '@angular/core';

export class AppInjector {

private static injector: Injector;

static setInjector(injector: Injector) {

        AppInjector.injector = injector;

    }

static getInjector(): Injector {

return AppInjector.injector;

    }

}       

模块自举后，将模块的注入器存储在AppInjector类中。

main.ts

platformBrowserDynamic().bootstrapModule(AppModule).then((moduleRef) => {
    AppInjector.setInjector(moduleRef.injector);
});        

使用此注入器类分配依赖项 现在，我们可以修改基本组件以删除所有构造函数参数。

base.component.ts

@Component({
    template: ''
})    
export class BaseComponent {    
    protected utilitiesService: UtilitiesService;    
    protected loggingService: LoggingService;

constructor() {    
        // Manually retrieve the dependencies from the injector    
        // so that constructor has no dependencies that must be passed in from child    
        const injector = AppInjector.getInjector();    
        this.utilitiesService = injector.get(UtilitiesService);    
        this.loggingService = injector.get(LoggingService);    
        this.logNavigation();

    }

    protected logError(errorMessage: string) { . . . }    
    private logNavigation() { . . . }
}         

从基础组件继承子组件 现在，子组件只需要对自己的依赖项使用依赖项注入。

child.component.ts

@Component({ . . . })
export class ChildComponent extends BaseComponent {

constructor(private childDataService: ChildDataService) {    
    super();    
  }    
}            

参考：https://devblogs.microsoft.com/premier-developer/angular-how-to-simplify-components-with-typescript-inheritance/