flutter之网络请求dio请求拦截器简单示例

flutter一直很火的网络请求插件dio
直接上代码，写成一个类，可以直接使用
包含请求的封装，拦截器的封装

import 'package:dio/dio.dart';import 'dart:async';import 'dart:io';import './apidomain.dart';import './httpHeaders.dart';import 'package:shared_preferences/shared_preferences.dart';class DioUtil{    static Dio dio = new Dio();    //请求部分    static  Future request(url,{formData})async{        try{            Response response;            dio.options.headers = httpHeaders;            dio.options.contentType = ContentType.parse("application/json;charset=UTF-8");            if(formData == null){                response = await dio.post(serviceUrl+url);            }else{                response = await dio.post(serviceUrl+url,data:formData);            }            if(response.statusCode == 200){                return response;            }else{                throw Exception("接口异常R");            }        }catch(e){            print("网络出现错误${e}");        }    }    //拦截器部分    static tokenInter(){        dio.interceptors.add(InterceptorsWrapper(            onRequest:(RequestOptions options){                // 在发送请求之前做一些预处理                //我这边是在发送前到SharedPreferences（本地存储）中取出token的值，然后添加到请求头中                //dio.lock()是先锁定请求不发送出去，当整个取值添加到请求头后再dio.unlock()解锁发送出去                dio.lock();                Future<dynamic> future = Future(()async{                    SharedPreferences prefs =await SharedPreferences.getInstance();                    return prefs.getString("loginToken");                });                return future.then((value) {                    options.headers["Authorization"] = value;                    return options;                }).whenComplete(() => dio.unlock()); // unlock the dio            },            onResponse:(Response response) {                // 在返回响应数据之前做一些预处理                return response; // continue            },            onError: (DioError e) {                // 当请求失败时做一些预处理                return e;//continue            }        ));    }}

httpHeaders文件则是放一些请求头信息如下

const httpHeaders={    'Accept': 'application/json, text/plain, */*',    'Authorization': '666',    'Content-Type': 'application/json;charset=UTF-8',    'Origin': 'http://localhost:8080',    'Referer': 'http://localhost:8080/',    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.103 Safari/537.36',};

apidomain文件则是放api的地址信息如下

const serviceUrl = 'http://39.xxx.xxx.xx:8080';