没有AuthHttp的提供者！ Angular2-Jwt提供商问题

至少我以为我提供的正确.以下是我的app.module文件的相关片段以及我使用AuthHttp的服务.我按照自述文件中的配置创建了提供AuthHttp的工厂方法,但是在我的服务中无法识别它存在持续存在的问题.我已经阅读了有关嵌套依赖注入的文献,我觉得我正在做正确的事情.

app.module.ts

import { Http,RequestOptions } from '@angular/http';
import { provideAuth,AuthHttp,AuthConfig } from 'angular2-jwt/angular2-jwt';

export function authHttpServiceFactory(http: Http,options: RequestOptions) {
  return new AuthHttp(new AuthConfig(),http,options);
}

@NgModule({
    declarations: [
        AppComponent,ButtonFormComponent,...
imports: [
        BrowserModule,FormsModule,HttpModule,RouterModule,AppRoutingModule
    ],providers: [
        {
            provide: LocationStrategy,useClass: HashLocationStrategy
        },{
            provide: AuthHttp,useFactory: authHttpServiceFactory,deps: [Http,RequestOptions]
        },

employee.service.ts

import { AuthHttp } from 'angular2-jwt/angular2-jwt';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/map';
import 'rxjs/add/observable/throw';

import { ApiSettings } from './api-settings';


@Injectable()
export class EmployeeService {
    api: String;
    auth: String;
    constructor(private http: Http,private authHttp: AuthHttp) {
        this.api = ApiSettings.API;
        this.auth = ApiSettings.Auth;
    }

import { AuthHttp,AUTH_PROVIDERS,provideAuth,AuthConfig } from 
    'angular2-jwt/angular2-jwt';

    @NgModule({
       providers: [AUTH_PROVIDERS]
    })