角度4.2。x拦截器未被执行

-角度4.2.4

我正试图使用以下角度代码拦截服务

import {Injectable} from '@angular/core';
import {HttpEvent, HttpInterceptor, HttpHandler, HttpRequest} from 
'@angular/common/http';
import { Observable } from 'rxjs/Rx';
export class LocalHttpClientInterceptor implements HttpInterceptor {
intercept(req: HttpRequest<any>, next: HttpHandler): 
Observable<HttpEvent<any>> {
  const username = 'me';
  const password = 'blahblah';
  const authReq = req.clone({headers: req.headers.set('Authorization', 
'Basic ' + btoa(username + ':' + password))});
  return next.handle(authReq);
  }
 }

import { LocalHttpClientInterceptor } from './local-http-client-
interceptor';
  @NgModule({
   imports: [
   CommonModule,
   FormsModule,
   ReactiveFormsModule,
   MdAutocompleteModule,
   MdInputModule,
   MdIconModule,
   HttpModule,
   MdGridListModule,
   FlexLayoutModule
 ],
 declarations: [ UserSearchComponent, ObjectComponent],
 exports: [UserSearchComponent, ObjectComponent, FlexLayoutModule],
 providers : [{
 provide: HTTP_INTERCEPTORS,
 useClass: LocalHttpClientInterceptor,
 multi: true,
 }, UserSearchService, LocalHttpClientService, StorageService]
})
 export class SharedModule { }

我可以看到intercept函数定义处的调试点被触发,但在完成一些服务调用后,intercept内部的代码并没有被调用。

我使用@angular/http中的angular-http调用服务,使用get、options和post方法