angular2 http request with headers, do not send
<p>Quite new to angular2 I try to build a data service and I want to add to each request headers</p>

<p>here is what I try but the headers won't be sent</p>

<pre><code>import { Injectable } from '@angular/core';
import { Http, Response, Headers } from '@angular/http';
import 'rxjs/add/operator/map'
import { Observable } from 'rxjs/Observable';
import { Configuration } from '../app.constants';
import { AuthenticationService } from '../services/';

@Injectable()
export class DataService {

    private actionUrl: string;
    private headers: Headers;
    private token;


    constructor(private _http: Http,
                private _configuration: Configuration

                //private authenticationService: AuthenticationService

    ) {

        var currentUser = JSON.parse(localStorage.getItem('currentUser'));

        if(currentUser)
            this.token = currentUser.token;

        this.actionUrl = _configuration.ServerWithApiUrl + 'patients';

        this.headers = new Headers();

        this.headers.append('Content-Type', 'application/x-www-form-urlencoded');
        this.headers.append('Accept', 'application/json');
        this.headers.append('Authorization', 'Bearer ' + this.token);
    }

    public GetAll = (): Observable&lt;any&gt; =&gt; {
        return this._http.get(this.actionUrl, this.headers).map((response: Response) =&gt; &lt;any&gt;response.json());
    }
}
</code></pre>

<p>how to do it properly or why this do not work?</p>