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如何在Flutter中实现Dio的二次封装
如何在Flutter中实现Dio的二次封装？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。
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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 LoginEntity DioManager().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 List DioManager().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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