flutter dio 请求封装（空安全）

一、添加依赖

dio: ^5.3.2

二、请求封装

class HttpHelper {static Dio? mDio;static BaseOptions? options;static HttpHelper? httpHelper;CancelToken cancelToken = CancelToken();static const String GET = 'get';static const String POST = 'post';static const String PUT = 'put';static const String PATCH = 'patch';static const String DELETE = 'delete';static HttpHelper? get instance => getInstance();static Dio? get dio => getDio();static HttpHelper? getInstance() {httpHelper ??= HttpHelper();return httpHelper;}static Dio? getDio() {final token = GetStorage().read('token');final Map<String, dynamic> headerMap = {};if (token != null) {headerMap.putIfAbsent("Authorization", () => "Bearer $token");}options = BaseOptions(//请求基地址,可以包含子路径baseUrl: Api.BASE_URL,//连接服务器超时时间，单位是毫秒.connectTimeout: const Duration(seconds: 10),//2.x中为接收数据的最长时限receiveTimeout: const Duration(seconds: 5),//Http请求头.headers: headerMap,// 请求的Content-Type，默认值是"application/json; charset=utf-8".//   /// 如果您想以"application/x-www-form-urlencoded"格式编码请求数据,//   /// 可以设置此选项为 `Headers.formUrlEncodedContentType`,  这样[Dio]//   /// 就会自动编码请求体.contentType: Headers.jsonContentType,/// [responseType] 表示期望以那种格式(方式)接受响应数据。/// 目前 [ResponseType] 接受三种类型 `JSON`, `STREAM`, `PLAIN`.////// 默认值是 `JSON`, 当响应头中content-type为"application/json"时，dio 会自动将响应内容转化为json对象。/// 如果想以二进制方式接受响应数据，如下载一个二进制文件，那么可以使用 `STREAM`.////// 如果想以文本(字符串)格式接收响应数据，请使用 `PLAIN`.responseType: ResponseType.json,);mDio = Dio(options);mDio?.interceptors.add(interceptorsWrapper());mDio?.httpClientAdapter = IOHttpClientAdapter(createHttpClient: () {final client = HttpClient();// Config the client.client.findProxy = (uri) {// Forward all request to proxy "localhost:8888".// Be aware, the proxy should went through you running device,// not the host platform.return 'PROXY 192.168.0.191:8089';};// You can also create a new HttpClient for Dio instead of returning,// but a client must being returned here.return client;},);return mDio;}static InterceptorsWrapper interceptorsWrapper() {return InterceptorsWrapper(onRequest: (options, handler) {// Do something before request is sentreturn handler.next(options); //continue// 如果你想完成请求并返回一些自定义数据，你可以resolve一个Response对象 `handler.resolve(response)`。// 这样请求将会被终止，上层then会被调用，then中返回的数据将是你的自定义response.//// 如果你想终止请求并触发一个错误,你可以返回一个`DioError`对象,如`handler.reject(error)`，// 这样请求将被中止并触发异常，上层catchError会被调用。}, onResponse: (response, handler) {// Do something with response datareturn handler.next(response); // continue// 如果你想终止请求并触发一个错误,你可以 reject 一个`DioError`对象,如`handler.reject(error)`，// 这样请求将被中止并触发异常，上层catchError会被调用。}, onError: (DioError e, handler) {// Do something with response errorif (e.response != null) {if (e.response?.statusCode == 401) {ToastMsg.show("当前登录已过期，请重新登录！");Future.delayed(const Duration(milliseconds: 1000), () {Get.offAllNamed(AppRoutes.LOGIN);});} else if (e.response?.statusCode == 403) {ToastMsg.show("暂无权限访问，请联系管理员！");} else {ToastMsg.show("系统内部异常！");}}return handler.next(e); //continue// 如果你想完成请求并返回一些自定义数据，可以resolve 一个`Response`,如`handler.resolve(response)`。// 这样请求将会被终止，上层then会被调用，then中返回的数据将是你的自定义response.});}///Get请求Future<BaseRes<T>> getHttp<T>(String url, parameters,{loading = true}) async {return await getResponse<T>(url, method: GET, parameters: parameters,loading:loading);}Future<BaseRes<T>> postHttp<T>(String url, parameters,{loading = true}) async {///定义请求参数parameters = parameters ?? <String, dynamic>{};return await getResponse<T>(url, method: POST, parameters: parameters,loading:loading);}Future<BaseRes<T>> putHttp<T>(String url, parameters,{loading = true}) async {///定义请求参数parameters = parameters ?? <String, dynamic>{};return await getResponse<T>(url, method: PUT, parameters: parameters,loading:loading);}Future<BaseRes<T>> deleteHttp<T>(String url, parameters,{loading = true}) async {///定义请求参数parameters = parameters ?? <String, dynamic>{};return await getResponse<T>(url, method: DELETE, parameters: parameters,loading:loading);}/** 下载文件*/downloadFile(urlPath, savePath, onReceiveProgress) async {Response? response;try {response = await dio?.download(urlPath, savePath,onReceiveProgress: onReceiveProgress);} on DioError catch (e) {formatError(e);}return response?.data;}Future<BaseRes<T>> getResponse<T>(String url, {required String method,parameters,loading,}) async {//这里指定response自动转成map,不指定的话有可能是String类型Response<Map<String, dynamic>>? response;if(loading) {ToastMsg.showLoading();}switch (method) {case GET:response = await dio?.get(url,queryParameters: parameters ?? <String, dynamic>{});break;case PUT:response = await dio?.put(url,queryParameters: parameters ?? <String, dynamic>{});break;case DELETE:response = await dio?.delete(url,queryParameters: parameters ?? <String, dynamic>{});break;default:response =await dio?.post(url, data: parameters ?? <String, dynamic>{});break;}if(loading) {ToastMsg.cancelLoading();}//200代表网络请求成功if (response?.statusCode == 200) {/// 将后台的data字段转成自己想要的数据/数据集,code根据后端实际返回进行判断访问结果BaseRes<T> bean = BaseRes.fromJson(response?.data);return bean;} else if (response?.statusCode == 401) {ToastMsg.show("当前登录已过期，请重新登录！");Future.delayed(const Duration(milliseconds: 1000), () {Get.offAllNamed(AppRoutes.LOGIN);});} else if (response?.statusCode == 403) {ToastMsg.show("暂无权限访问，请联系管理员！");} else {ToastMsg.show("系统内部异常！");}throw Exception('${response?.statusCode}+${response?.statusMessage}');}void formatError(DioError e) {print(e.message);}/** 取消请求* 同一个cancel token 可以用于多个请求，当一个cancel token取消时，所有使用该cancel token的请求都会被取消。*/void cancelRequests(CancelToken token) {token.cancel("cancelled");}
}

三、封装统一返回类

@JsonSerializable()
class BaseRes<T>{BaseRes(this.msg, this.code, this.data);late String msg;late int code;late T data;BaseRes.fromJson(Map<String, dynamic>? json) {if (json?['data'] != null && json?['data'] != 'null') {data = JsonConvert.fromJsonAsT<T>(json?['data']) as T;}msg = json?['msg'];code = json?['code'];}Map<String, dynamic> toJson() {final Map<String, dynamic> data = <String, dynamic>{};if (this.data != null) {data['data'] = this.data;}data['code'] = this.code;data['msg'] = this.msg;return data;}
}

四、使用

// Entity类使用的是JsonToDartBeanAction生成BaseRes<UserInfoEntity>? res = await HttpHelper.instance?.getHttp(Api.GET_USER_INGO,null,loading: false);if(res?.code == 200 && res?.data != null) {state.userInfo = res!.data.obs;}