Angular 2 – 预检的响应具有无效的HTTP状态代码401

>选项http://…/my_REST_Service/ 401(未经授权)
> XMLHttpRequest无法加载http://…/my_REST_Service/.预检的响应具有无效的HTTP状态代码401

我如何尝试获取我想要的数据：

@Injectable()
export class ModelsComponent implements OnInit {

    private restRoot = 'http://.../my_REST_Service';
    private data;

    constructor(private http: Http) { }

    ngOnInit() {
        this.getModels().subscribe(res => {
            this.data = res; 
            console.log(this.data);
        });
    }

    authHeaders() {
        let username: string = 'xxxx';
        let password: string = 'xxxx';

        let token: string = btoa(username + ":" + password);

        let headers: Headers = new Headers();
        headers.append('Access-Control-Expose-Headers','Authorization');
        headers.append('Authorization','Basic ' + token);
        headers.append("Access-Control-Allow-Origin","http://localhost:4200/");
        headers.append("Access-Control-Allow-Methods","*");
        headers.append("Access-Control-Allow-Headers","Accept,Accept-Charset,Accept-Encoding,Accept-Language,Authorization,Connection,Content-Type,Cookie,DNT,Host,Keep-Alive,Origin,Referer,User-Agent,X-CSRF-Token,X-Requested-With");
        headers.append("Access-Control-Allow-Credentials","true");

        return headers;
    }

    getModels(): Observable<any> {
        return this.http.get(this.restRoot,{
                    headers: this.authHeaders(),withCredentials: true        <- from a similar issue
               }).map(res => res.json());
    }
}

我的服务器配置如下：

Header set Access-Control-Allow-Origin "http://localhost:4200"
Header set Access-Control-Allow-Headers "Accept,X-Requested-With"
Header set Access-Control-Allow-Methods "*"
Header set Access-Control-Allow-Credentials "true"   
Header set Access-Control-Expose-Headers "Authorization"       <- from a similar issue

我知道还有其他相同/类似的问题.但我仍然不知道该做什么或怎么做.
如果有人可以帮我解决我的代码,我真的很感激！