angular8如何封装http服务

import { NgModule } from '@angular/core';

import { BrowserModule } from '@angular/platform-browser';

import { RouteReuseStrategy } from '@angular/router';

// 导入关键模块

import { HttpClientModule } from '@angular/common/http';

import { IonicModule, IonicRouteStrategy } from '@ionic/angular';

import { SplashScreen } from '@ionic-native/splash-screen/ngx';

import { StatusBar } from '@ionic-native/status-bar/ngx';

import { AppRoutingModule } from './app-routing.module';

import { AppComponent } from './app.component';

@NgModule({

  declarations: [AppComponent],

  entryComponents: [],

  imports: [BrowserModule, IonicModule.forRoot(), AppRoutingModule, HttpClientModule],

  providers: [

    StatusBar,

    SplashScreen,

    { provide: RouteReuseStrategy, useClass: IonicRouteStrategy }

  ],

  bootstrap: [AppComponent]

})

export class AppModule { }

import { Injectable } from '@angular/core';

import { HttpClient, HttpParams, HttpErrorResponse } from '@angular/common/http';

import { Observable, throwError } from 'rxjs';

import { catchError } from 'rxjs/operators';

@Injectable({

  providedIn: 'root'

})

export class HttpService {

  private http: any;

  constructor(private Http: HttpClient) {

    this.http = Http;

  }

  // get方法

  public get(url: string, options?: Object, params?: Object): Observable<{}> {

    let httpParams = new HttpParams();

    if (params) {

      for (const key in params) {

        if (params[key] === false || params[key]) {

          httpParams = httpParams.set(key, params[key]);

        }

      }

    }

    return this.http.get(url, { headers: options, params: httpParams }).pipe(catchError(this.handleError));

  }

  // post方法

  public post(url: string, body: any = null, options?: Object): Observable<{}> {

    return this.http.post(url, body, options).pipe(catchError(this.handleError));

  }

  // post表单

  public postForm(url: string, body: any = null, options?: Object): Observable<{}> {

    let httpParams = new HttpParams();

    if (body) {

      for (const key in body) {

        if (body[key] === false || body[key]) {

          httpParams = httpParams.set(key, body[key]);

        }

      }

    }

    return this.http.post(url, httpParams, options).pipe(catchError(this.handleError));

  }

  /**

   * 处理请求失败的错误

   * @param error HttpErrorResponse

   */

  private handleError(error: HttpErrorResponse) {

    if (error.error instanceof ErrorEvent) {

      console.error('An error occurred:', error.error.message);

    } else {

      console.error(

        `Backend returned code ${error.status}, ` +

        `body was: ${error.error}`);

    }

    console.log(error);

    return throwError(error.error);

  }

}