FlutterDio中怎么实现二次封装，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。
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目录：
DioManager：Dio辅助类NWMethod：请求方法，get、post等 NWApi：大家都知道 EntityFactory：json转换辅助工厂，把json转为T BaseEntity：数据基类，返回的参数为 {“code”: 0, “message”: “”, “data”: {}} BaseListEntity：数据基类2，返回的参数为 {“code”: 0, “message”: “”, “data”: []} ErrorEntity：请求报错基类，{“code”: 0, “message”: “”}
EntityFactory：
class EntityFactory { static T generateOBJ(json) { if (json == null) { return null; }//可以在这里加入任何需要并且可以转换的类型，例如下面// else if (T.toString() == "LoginEntity") {// return LoginEntity.fromJson(json) as T;// } else { return json as T; } }}
BaseEntity：
class BaseEntity { int code; String message; T data; BaseEntity({this.code, this.message, this.data}); factory BaseEntity.fromJson(json) { return BaseEntity( code: json["code"], message: json["msg"], // data值需要经过工厂转换为我们传进来的类型 data: EntityFactory.generateOBJ(json["data"]), ); }}
BaseListEntity：
class BaseListEntity { int code; String message; List data; BaseListEntity({this.code, this.message, this.data}); factory BaseListEntity.fromJson(json) { List mData = List(); if (json['data'] != null) { //遍历data并转换为我们传进来的类型 (json['data'] as List).forEach((v) { mData.add(EntityFactory.generateOBJ(v)); }); } return BaseListEntity( code: json["code"], message: json["msg"], data: mData, ); } }
ErrorEntity：
class ErrorEntity { int code; String message; ErrorEntity({this.code, this.message});}
NWApi：
class NWApi { static final baseApi = "https://easy-mock.bookset.io/mock/5dfae67d4946c20a50841fa7/example/"; static final loginPath = "user/login";//接口返回：{"code": int, "message": "String", "data": {"account": "String", "password": "String"}} static final queryListPath = "/query/list";//接口返回：{"code": ing, "message": "String", "data": [int, int, String, int, String, int]} static final queryListJsonPath = "/query/listjson";//接口返回：{"code": int, "message": "String", "data": [{"account": "String", "password": "String"}， {"account": "String", "password": "String"}]}}
NWMethod：
enum NWMethod { GET, POST, DELETE, PUT}//使用：NWMethodValues[NWMethod.POST]const NWMethodValues = { NWMethod.GET: "get", NWMethod.POST: "post", NWMethod.DELETE: "delete", NWMethod.PUT: "put"};
下面就可以进行正式的封装了：
第一步是创建Dio的单例辅助类，并初始化Dio和对Dio进行一些全局的参数设置：
import 'package:dio/dio.dart';import 'package:flutter_app/network/NWApi.dart';import 'package:flutter_app/utils/PrintUtil.dart';class DioManager { static final DioManager _shared = DioManager._internal(); factory DioManager() => _shared; Dio dio; DioManager._internal() { if (dio == null) { BaseOptions options = BaseOptions( baseUrl: NWApi.baseApi, contentType: Headers.jsonContentType, responseType: ResponseType.json, receiveDataWhenStatusError: false, connectTimeout: 30000, receiveTimeout: 3000, ); dio = Dio(options); } }}
第二步对请求进行封装，在我的想法中 {“code”: 0, “message”: “”, “data”: {}} 和 {“code”: 0, “message”: “”, “data”: []} 这两种数据是要分开两个请求方法的：
// 请求，返回参数为 T // method：请求方法，NWMethod.POST等 // path：请求地址 // params：请求参数 // success：请求成功回调 // error：请求失败回调 Future request(NWMethod method, String path, {Map params, Function(T) success, Function(ErrorEntity) error}) async { try { Response response = await dio.request(path, queryParameters: params, options: Options(method: NWMethodValues[method])); if (response != null) { BaseEntity entity = BaseEntity.fromJson(response.data); if (entity.code == 0) { success(entity.data); } else { error(ErrorEntity(code: entity.code, message: entity.message)); } } else { error(ErrorEntity(code: -1, message: "未知错误")); } } on DioError catch(e) { error(createErrorEntity(e)); } } // 请求，返回参数为 List // method：请求方法，NWMethod.POST等 // path：请求地址 // params：请求参数 // success：请求成功回调 // error：请求失败回调 Future requestList(NWMethod method, String path, {Map params, Function(List) success, Function(ErrorEntity) error}) async { try { Response response = await dio.request(path, queryParameters: params, options: Options(method: NWMethodValues[method])); if (response != null) { BaseListEntity entity = BaseListEntity.fromJson(response.data); if (entity.code == 0) { success(entity.data); } else { error(ErrorEntity(code: entity.code, message: entity.message)); } } else { error(ErrorEntity(code: -1, message: "未知错误")); } } on DioError catch(e) { error(createErrorEntity(e)); } }
提取请求错误处理方法createErrorEntity：
// 错误信息 ErrorEntity createErrorEntity(DioError error) { switch (error.type) { case DioErrorType.CANCEL:{ return ErrorEntity(code: -1, message: "请求取消"); } break; case DioErrorType.CONNECT_TIMEOUT:{ return ErrorEntity(code: -1, message: "连接超时"); } break; case DioErrorType.SEND_TIMEOUT:{ return ErrorEntity(code: -1, message: "请求超时"); } break; case DioErrorType.RECEIVE_TIMEOUT:{ return ErrorEntity(code: -1, message: "响应超时"); } break; case DioErrorType.RESPONSE:{ try { int errCode = error.response.statusCode; String errMsg = error.response.statusMessage; return ErrorEntity(code: errCode, message: errMsg);// switch (errCode) {// case 400: {// return ErrorEntity(code: errCode, message: "请求语法错误");// }// break;// case 403: {// return ErrorEntity(code: errCode, message: "服务器拒绝执行");// }// break;// case 404: {// return ErrorEntity(code: errCode, message: "无法连接服务器");// }// break;// case 405: {// return ErrorEntity(code: errCode, message: "请求方法被禁止");// }// break;// case 500: {// return ErrorEntity(code: errCode, message: "服务器内部错误");// }// break;// case 502: {// return ErrorEntity(code: errCode, message: "无效的请求");// }// break;// case 503: {// return ErrorEntity(code: errCode, message: "服务器挂了");// }// break;// case 505: {// return ErrorEntity(code: errCode, message: "不支持HTTP协议请求");// }// break;// default: {// return ErrorEntity(code: errCode, message: "未知错误");// }// } } on Exception catch(_) { return ErrorEntity(code: -1, message: "未知错误"); } } break; default: { return ErrorEntity(code: -1, message: error.message); } } }
完整的 DioManager 类代码：
import 'package:dio/dio.dart';import 'package:flutter_app/network/entity/BaseEntity.dart';import 'package:flutter_app/network/entity/BaseListEntity.dart';import 'package:flutter_app/network/entity/EntityFactory.dart';import 'package:flutter_app/network/entity/ErrorEntity.dart';import 'package:flutter_app/network/NWApi.dart';import 'package:flutter_app/network/NWMethod.dart';class DioManager { static final DioManager _shared = DioManager._internal(); factory DioManager() => _shared; Dio dio; DioManager._internal() { if (dio == null) { BaseOptions options = BaseOptions( baseUrl: NWApi.baseApi, contentType: Headers.jsonContentType, responseType: ResponseType.json, receiveDataWhenStatusError: false, connectTimeout: 30000, receiveTimeout: 3000, ); dio = Dio(options); } } // 请求，返回参数为 T // method：请求方法，NWMethod.POST等 // path：请求地址 // params：请求参数 // success：请求成功回调 // error：请求失败回调 Future request(NWMethod method, String path, {Map params, Function(T) success, Function(ErrorEntity) error}) async { try { Response response = await dio.request(path, queryParameters: params, options: Options(method: NWMethodValues[method])); if (response != null) { BaseEntity entity = BaseEntity.fromJson(response.data); if (entity.code == 0) { success(entity.data); } else { error(ErrorEntity(code: entity.code, message: entity.message)); } } else { error(ErrorEntity(code: -1, message: "未知错误")); } } on DioError catch(e) { error(createErrorEntity(e)); } } // 请求，返回参数为 List // method：请求方法，NWMethod.POST等 // path：请求地址 // params：请求参数 // success：请求成功回调 // error：请求失败回调 Future requestList(NWMethod method, String path, {Map params, Function(List) success, Function(ErrorEntity) error}) async { try { Response response = await dio.request(path, queryParameters: params, options: Options(method: NWMethodValues[method])); if (response != null) { BaseListEntity entity = BaseListEntity.fromJson(response.data); if (entity.code == 0) { success(entity.data); } else { error(ErrorEntity(code: entity.code, message: entity.message)); } } else { error(ErrorEntity(code: -1, message: "未知错误")); } } on DioError catch(e) { error(createErrorEntity(e)); } } // 错误信息 ErrorEntity createErrorEntity(DioError error) { switch (error.type) { case DioErrorType.CANCEL:{ return ErrorEntity(code: -1, message: "请求取消"); } break; case DioErrorType.CONNECT_TIMEOUT:{ return ErrorEntity(code: -1, message: "连接超时"); } break; case DioErrorType.SEND_TIMEOUT:{ return ErrorEntity(code: -1, message: "请求超时"); } break; case DioErrorType.RECEIVE_TIMEOUT:{ return ErrorEntity(code: -1, message: "响应超时"); } break; case DioErrorType.RESPONSE:{ try { int errCode = error.response.statusCode; String errMsg = error.response.statusMessage; return ErrorEntity(code: "$errCode", message: errMsg);// switch (errCode) {// case 400: {// return ErrorEntity(code: errCode, message: "请求语法错误");// }// break;// case 403: {// return ErrorEntity(code: errCode, message: "服务器拒绝执行");// }// break;// case 404: {// return ErrorEntity(code: errCode, message: "无法连接服务器");// }// break;// case 405: {// return ErrorEntity(code: errCode, message: "请求方法被禁止");// }// break;// case 500: {// return ErrorEntity(code: errCode, message: "服务器内部错误");// }// break;// case 502: {// return ErrorEntity(code: errCode, message: "无效的请求");// }// break;// case 503: {// return ErrorEntity(code: errCode, message: "服务器挂了");// }// break;// case 505: {// return ErrorEntity(code: errCode, message: "不支持HTTP协议请求");// }// break;// default: {// return ErrorEntity(code: errCode, message: "未知错误");// }// } } on Exception catch(_) { return ErrorEntity(code: -1, message: "未知错误"); } } break; default: { return ErrorEntity(code: -1, message: error.message); } } }}
使用：
// 返回 LoginEntityDioManager().request( NWMethod.POST, NWApi.loginPath, params: {"account": "421789838@qq.com", "password": "123456"}, success: (data) { print("success data = $data"}); }, error: (error) { print("error code = ${error.code}, massage = ${error.message}"); });// 返回 ListDioManager().requestList( NWMethod.POST, NWApi.queryListJsonPath, params: {"account": "421789838@qq.com", "password": "123456"}, success: (data) { print("success data = $data"}); }, error: (error) { print("error code = ${error.code}, massage = ${error.message}"); });
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