我无法在angular2中导入json

import { Component } from '@angular/core';
import { Http } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';

@Component({
  selector: 'app-root',
  template: '<div>{{ jsonData | json }}</div>'
})
export class AppComponent {
  jsonData: any;

  constructor(private http: Http) {
    this.getJSON().subscribe(data => {
      this.jsonData = data;
    });
  }

  public getJSON(): Observable<any> {
    return this.http.get('path/to/data.json')
      .map((res: any) => res.json());
  }
}