Flutter完整的Dio网络框架null空安全二次封装。

所需依赖添加在项目中的pubspec.yaml中：

dio: ^4.0.6 #网络请求
connectivity_plus: ^2.3.6 #网络监测
pretty_dio_logger: ^1.1.1 #日志打印

class HttpRequest {// 单例模式使用Http类，static final HttpRequest _instance = HttpRequest._internal();factory HttpRequest() => _instance;static late final Dio dio;/// 内部构造方法HttpRequest._internal() {/// 初始化dioBaseOptions optiOns= BaseOptions(connectTimeout: HttpOptions.connectTimeout,receiveTimeout: HttpOptions.receiveTimeout,sendTimeout: HttpOptions.sendTimeout,baseUrl: HttpOptions.baseUrl);dio = Dio(options);/// 添加各种拦截器dio.interceptors.add(ErrorInterceptor());dio.interceptors.add(PrettyDioLogger(requestHeader: true,requestBody: true,responseHeader: true,responseBody: true));}/// 封装request方法Future request({required String path,required HttpMethod method,dynamic data,Map? queryParameters,bool showLoading = true,bool showErrorMessage = true,}) async {const Map methodValues = {HttpMethod.get: &＃39;get&＃39;,HttpMethod.post: &＃39;post&＃39;,HttpMethod.put: &＃39;put&＃39;,HttpMethod.delete: &＃39;delete&＃39;,HttpMethod.patch: &＃39;patch&＃39;,HttpMethod.head: &＃39;head&＃39;};//动态添加header头Map headers = Map();headers["version"] = "1.0.0";Options optiOns= Options(method: methodValues[method],headers: headers,);try {if (showLoading) {EasyLoading.show(status: &＃39;loading...&＃39;);}Response respOnse= await HttpRequest.dio.request(path,data: data,queryParameters: queryParameters,options: options,);return response.data;} on DioError catch (error) {HttpException httpException = error.error;if (showErrorMessage) {EasyLoading.showToast(httpException.msg);}} finally {if (showLoading) {EasyLoading.dismiss();}}}
}enum HttpMethod {get,post,delete,put,patch,head,
}

class ErrorInterceptor extends Interceptor {@overridevoid onError(DioError err, ErrorInterceptorHandler handler) async {/// 根据DioError创建HttpExceptionHttpException httpException = HttpException.create(err);/// dio默认的错误实例，如果是没有网络，只能得到一个未知错误，无法精准的得知是否是无网络的情况/// 这里对于断网的情况，给一个特殊的code和msgif (err.type == DioErrorType.other) {var cOnnectivityResult= await (Connectivity().checkConnectivity());if (cOnnectivityResult== ConnectivityResult.none) {httpException = HttpException(code: -100, msg: &＃39;None Network.&＃39;);}}/// 将自定义的HttpExceptionerr.error = httpException;/// 调用父类，回到dio框架super.onError(err, handler);}
}

class HttpException implements Exception {final int code;final String msg;HttpException({this.code = -1,this.msg = &＃39;unknow error&＃39;,});@overrideString toString() {return &＃39;Http Error [$code]: $msg&＃39;;}factory HttpException.create(DioError error) {/// dio异常switch (error.type) {case DioErrorType.cancel:{return HttpException(code: -1, msg: &＃39;request cancel&＃39;);}case DioErrorType.connectTimeout:{return HttpException(code: -1, msg: &＃39;connect timeout&＃39;);}case DioErrorType.sendTimeout:{return HttpException(code: -1, msg: &＃39;send timeout&＃39;);}case DioErrorType.receiveTimeout:{return HttpException(code: -1, msg: &＃39;receive timeout&＃39;);}case DioErrorType.response:{try {int statusCode = error.response?.statusCode ?? 0;// String errMsg = error.response.statusMessage;// return ErrorEntity(code: errCode, message: errMsg);switch (statusCode) {case 400:{return HttpException(code: statusCode, msg: &＃39;Request syntax error&＃39;);}case 401:{return HttpException(code: statusCode, msg: &＃39;Without permission&＃39;);}case 403:{return HttpException(code: statusCode, msg: &＃39;Server rejects execution&＃39;);}case 404:{return HttpException(code: statusCode, msg: &＃39;Unable to connect to server&＃39;);}case 405:{return HttpException(code: statusCode, msg: &＃39;The request method is disabled&＃39;);}case 500:{return HttpException(code: statusCode, msg: &＃39;Server internal error&＃39;);}case 502:{return HttpException(code: statusCode, msg: &＃39;Invalid request&＃39;);}case 503:{return HttpException(code: statusCode, msg: &＃39;The server is down.&＃39;);}case 505:{return HttpException(code: statusCode, msg: &＃39;HTTP requests are not supported&＃39;);}default:{return HttpException(code: statusCode, msg: error.response?.statusMessage ?? &＃39;unknow error&＃39;);}}} on Exception catch (_) {return HttpException(code: -1, msg: &＃39;unknow error&＃39;);}}default:{return HttpException(code: -1, msg: error.message);}}}
}

class HttpOptions {/// 超时时间；单位是msstatic const int cOnnectTimeout= 15000;static const int receiveTimeout = 15000;static const int sendTimeout = 15000;/// 地址域名前缀static const String baseUrl = &＃39;************&＃39;;}

/// 调用底层的request，重新提供get，post等方便方法
class HttpUtils {static HttpRequest httpRequest = HttpRequest();/// getstatic Future get({required String path,Map? queryParameters,bool showLoading = true,bool showErrorMessage = true,}) {return httpRequest.request(path: path,method: HttpMethod.get,queryParameters: queryParameters,showLoading: showLoading,showErrorMessage: showErrorMessage,);}/// poststatic Future post({required String path,required HttpMethod method,dynamic data,bool showLoading = true,bool showErrorMessage = true,}) {return httpRequest.request(path: path,method: HttpMethod.post,data: data,showLoading: showLoading,showErrorMessage: showErrorMessage,);}}