Flutter Dio二次封装

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 = new 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 LoginEntity
DioManager().request(
  NWMethod.POST,
  NWApi.loginPath,
  params: {"account": "[email protected]", "password": "123456"},
  success: (data) {
      print("success data = $data"});
  }, error: (error) {
      print("error code = ${error.code}, massage = ${error.message}");
  }
);

// 返回 List
DioManager().requestList(
  NWMethod.POST,
  NWApi.queryListJsonPath,
  params: {"account": "[email protected]", "password": "123456"},
  success: (data) {
      print("success data = $data"});
  }, error: (error) {
      print("error code = ${error.code}, massage = ${error.message}");
  }
);