如何正确实例化AuthenticationService？我认为在提供商的app.module.ts中提及它会照顾到这一点.

提前致谢

这是AuthenticationService.ts：

import { Injectable } from '@angular/core';
import { /*HTTP_PROVIDERS,*/Http,Headers } from '@angular/http';
import { AuthHttp } from 'angular2-jwt';

@Injectable()
export class AuthenticationService {

    jwtToken: any;

    constructor(public authHttp: AuthHttp) { }

    jwtHeader = new Headers({
        "Content-Type": "application/json","alg": "HS256","typ": "JWT"
    });


    Login(username: string,password: string) {

        console.log("from authService: " + username);

        this.authHttp.post('/api/AuthResponse',JSON.stringify({
                "username:": username,"password:": password
            }),{ headers: this.jwtHeader }
        ).subscribe(data => this.jwtToken = data,() => console.log(this.jwtToken));

        return this.jwtToken;
    }

}

这是LoginComponent.ts：

import { Component,OnInit } from '@angular/core';
import { AuthenticationService } from './../../services/AuthenticationService';
import { AuthHttp,AuthConfig/*,AUTH_PROVIDERS,provideAuth*/ } from 'angular2-jwt';

@Component({
    selector: 'login',template: require('./login.component.html')
})
export class LoginComponent implements OnInit {
    username;
    password;

    constructor(authenticationService: AuthenticationService){}

    ngOnInit() {
        // reset login status
        //this.authenticationService.logout();

    }

    //private authService: AuthenticationService = new AuthenticationService(new AuthHttp(new AuthConfig(),new Http());

    login()
    {
        console.log(this.username);
        console.log(this.password);
        this.authenticationService.Login(this.username,this.password);
    }
}

app.module.ts

import { NgModule } from '@angular/core';
import { RouterModule } from '@angular/router';
import { UniversalModule } from 'angular2-universal';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http';
import { AuthHttp,AuthConfig,provideAuth } from 'angular2-jwt';

import { AuthenticationService } from './services/AuthenticationService';

import { AppComponent } from './components/app/app.component'
import { NavMenuComponent } from './components/navmenu/navmenu.component';
import { HomeComponent } from './components/home/home.component';
import { FetchDataComponent } from './components/fetchdata/fetchdata.component';
import { CounterComponent } from './components/counter/counter.component';
import { LoginComponent } from './components/login/login.component';


@NgModule({

    declarations: [
        AppComponent,NavMenuComponent,CounterComponent,FetchDataComponent,HomeComponent,LoginComponent
    ],imports: [
        UniversalModule,// Must be first import. This automatically imports BrowserModule,HttpModule,and JsonpModule too.
        FormsModule,RouterModule.forRoot([
            { path: '',redirectTo: 'home',pathMatch: 'full' },{ path: 'home',component: HomeComponent },{ path: 'counter',component: CounterComponent },{ path: 'fetch-data',component: FetchDataComponent },{ path: 'login',component: LoginComponent },{ path: '**',redirectTo: 'home' }
        ])
    ],providers: [
        AuthHttp,provideAuth({
            headerName: 'Authorization',headerPrefix: 'bearer',tokenName: 'token',tokenGetter: (() => localStorage.getItem('id_token')),globalHeaders: [{ 'Content-Type': 'application/json' }],noJwtError: true
        }),AuthenticationService
    ],bootstrap: [AppComponent]
})
export class AppModule {
}