Inexclipable tslint warnings

Ionic Framework ionic-v3
1

Hello,

I got tslint warnings when enter ionic serve. But I don’t understand why I got warnings like
'Http' is declared but never used.
But when I take a look on the file, the ‘Http’ module is used, that’s why I don’t understand why I got the warning.
Please help.

2

Provide your code so we can check if we can find the fault.

3 
import {Injectable}             from '@angular/core';
import {Http, Response, Headers} from '@angular/http';

@Injectable()
export class DataRestService {

  constructor(private http: Http) {
  }

  readData( {
    return this.http.post(xxxx);
  }
4

L2: import {Http, Response, Headers} from ‘@angular/http’;
‘Http’ is declared but never used.