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Flutter 网络请求 Dio 封装

在Flutter项目中使用网络请求的方式大致可分为两种，分别是Dart原生的网络请求 HttpClient类以及第三方开源的网络请求库。在Dart社区开源的第三方http请求库中Flutter 中文网开源的 Dio库人气最高。

下面我们先来比较下这两种网络请求方式，然后再看怎么基于 Dio库封装方便使用的网络请求工具类HttpManager。

网络请求库比较

HttClient类

Dart IO库中提供了用于发起Http请求的一些类，我们可以直接使用HttpClient来发起请求。使用HttpClient发起请求分为五步：

创建一个HttpClient

HttpClient httpClient = new HttpClient();
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打开Http连接，设置请求头

HttpClientRequest request = await httpClient.getUrl(uri);
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这一步可以使用任意Http Method，如httpClient.post(...)、httpClient.delete(...)等。如果包含Query参数，可以在构建uri时添加，如：

Uri uri=Uri(scheme: "https", host: "flutterchina.club", queryParameters: {
    "xx":"xx",
    "yy":"dd"
  });
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通过HttpClientRequest可以设置请求header，如：

request.headers.add("user-agent", "test");
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如果是post或put等可以携带请求体方法，可以通过HttpClientRequest对象发送request body，如：

String payload="...";
request.add(utf8.encode(payload)); 
//request.addStream(_inputStream); //可以直接添加输入流
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等待连接服务器

HttpClientResponse response = await request.close();
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这一步完成后，请求信息就已经发送给服务器了，返回一个HttpClientResponse对象，它包含响应头（header）和响应流(响应体的Stream)，接下来就可以通过读取响应流来获取响应内容。

读取响应内容

String responseBody = await response.transform(utf8.decoder).join();
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我们通过读取响应流来获取服务器返回的数据，在读取时我们可以设置编码格式，这里是utf8。

请求结束，关闭HttpClient

httpClient.close();
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关闭client后，通过该client发起的所有请求都会中止。

以上的步骤是dart原生网络HttpClient使用方式，可以发现直接使用HttpClient发起网络请求是比较麻烦的，很多事情都得手动处理，如果再涉及到文件上传/下载、Cookie管理等就会变得非常繁琐，并且HttpClient本身功能较弱，很多常用功能都不支持。

Dio库

dio是一个强大的Dart Http请求库，支持Restful API、FormData、拦截器、请求取消、Cookie管理、文件上传/下载、超时等...

pubspec.yaml 添加依赖

dependencies:
  dio: ^x.x.x #请使用pub上的最新版本
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导入引用并创建dio 实例

import 'package:dio/dio.dart';
Dio dio =  Dio();
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接下来就可以通过 dio实例来发起网络请求了，注意，一个dio实例可以发起多个http请求，一般来说，APP只有一个http数据源时，dio应该使用单例模式。

发起网络请求

Get 请求

Response response;
response=await dio.get("/test?id=12&name=cheney")
print(response.data.toString());
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Post请求

Response response;
response=await dio.post("/test",data:{"id":12,"name":"cheney"})
print(response.data.toString());
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以上就是Dio库网络请求的基本使用，是不是很简单，除了这些基本的用法，dio还支持请求配置、拦截器等，官方资料比较详细，故在这里不再赘述，详情可以参考dio主页： github.com/flutterchin… 。

封装Dio工具类

为什么要封装 dio

做一些公共处理，方便灵活的使用。

做那些封装

统一处理请求前缀；（ www.xx.com/api/v1 不用每个请求都加前缀）
统一输出请求或响应信息；
统一错误信息处理；
兼容多种网络请求、支持文件上传、下载；
支持同步回调与异步Future 两种形式
返回数据自动转json格式并默认解析公共数据模型；

类名	描述
HttpManager	网络请求管理类
HttpError	网络请求统一错误类
LogInterceptor	网络请求工具类

import 'dart:core';

import 'package:connectivity/connectivity.dart';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:flutter_common_utils/http/http_error.dart';
import 'package:flutter_common_utils/log_util.dart';

///http请求成功回调
typedef HttpSuccessCallback<T> = void Function(dynamic data);

///失败回调
typedef HttpFailureCallback = void Function(HttpError data);

///数据解析回调
typedef T JsonParse<T>(dynamic data);


/// @desc  封装 http 请求
/// @time 2019/3/15 10:35 AM
/// @author Cheney
class HttpManager {
  ///同一个CancelToken可以用于多个请求，当一个CancelToken取消时，所有使用该CancelToken的请求都会被取消，一个页面对应一个CancelToken。
  Map<String, CancelToken> _cancelTokens =  Map<String, CancelToken>();

  ///超时时间
  static const int CONNECT_TIMEOUT = 30000;
  static const int RECEIVE_TIMEOUT = 30000;

  /// http request methods
  static const String GET = 'get';
  static const String POST = 'post';

  Dio _client;

  static final HttpManager _instance = HttpManager._internal();

  factory HttpManager() => _instance;

  Dio get client => _client;

  /// 创建 dio 实例对象
  HttpManager._internal() {
    if (_client == null) {
      /// 全局属性：请求前缀、连接超时时间、响应超时时间
      BaseOptions options = BaseOptions(
        connectTimeout: CONNECT_TIMEOUT,
        receiveTimeout: RECEIVE_TIMEOUT,
      );
      _client = Dio(options);
    }
  }

  ///初始化公共属性
  ///
  /// [baseUrl] 地址前缀
  /// [connectTimeout] 连接超时赶时间
  /// [receiveTimeout] 接收超时赶时间
  /// [interceptors] 基础拦截器
  void init(
      {String baseUrl,
      int connectTimeout,
      int receiveTimeout,
      List<Interceptor> interceptors}) {
    _client.options = _client.options.merge(
      baseUrl: baseUrl,
      connectTimeout: connectTimeout,
      receiveTimeout: receiveTimeout,
    );
    if (interceptors != null && interceptors.isNotEmpty) {
      _client.interceptors..addAll(interceptors);
    }
  }

  ///Get网络请求
  ///
  ///[url] 网络请求地址不包含域名
  ///[params] url请求参数支持restful
  ///[options] 请求配置
  ///[successCallback] 请求成功回调
  ///[errorCallback] 请求失败回调
  ///[tag] 请求统一标识，用于取消网络请求
  void get({
    @required String url,
    Map<String, dynamic> params,
    Options options,
    HttpSuccessCallback successCallback,
    HttpFailureCallback errorCallback,
    @required String tag,
  }) async {
    _request(
      url: url,
      params: params,
      method: GET,
      successCallback: successCallback,
      errorCallback: errorCallback,
      tag: tag,
    );
  }

  ///post网络请求
  ///
  ///[url] 网络请求地址不包含域名
  ///[data] post 请求参数
  ///[params] url请求参数支持restful
  ///[options] 请求配置
  ///[successCallback] 请求成功回调
  ///[errorCallback] 请求失败回调
  ///[tag] 请求统一标识，用于取消网络请求
  void post({
    @required String url,
    data,
    Map<String, dynamic> params,
    Options options,
    HttpSuccessCallback successCallback,
    HttpFailureCallback errorCallback,
    @required String tag,
  }) async {
    _request(
      url: url,
      data: data,
      method: POST,
      params: params,
      successCallback: successCallback,
      errorCallback: errorCallback,
      tag: tag,
    );
  }

  ///统一网络请求
  ///
  ///[url] 网络请求地址不包含域名
  ///[data] post 请求参数
  ///[params] url请求参数支持restful
  ///[options] 请求配置
  ///[successCallback] 请求成功回调
  ///[errorCallback] 请求失败回调
  ///[tag] 请求统一标识，用于取消网络请求
  void _request({
    @required String url,
    String method,
    data,
    Map<String, dynamic> params,
    Options options,
    HttpSuccessCallback successCallback,
    HttpFailureCallback errorCallback,
    @required String tag,
  }) async {
    //检查网络是否连接
    ConnectivityResult connectivityResult =
        await (Connectivity().checkConnectivity());
    if (connectivityResult == ConnectivityResult.none) {
      if (errorCallback != null) {
        errorCallback(HttpError(HttpError.NETWORK_ERROR, "网络异常，请稍后重试！"));
      }
      LogUtil.v("请求网络异常，请稍后重试！");
      return;
    }

    //设置默认值
    params = params ?? {};
    method = method ?? 'GET';

    options?.method = method;

    options = options ??
        Options(
          method: method,
        );

    url = _restfulUrl(url, params);

    try {
      CancelToken cancelToken;
      if (tag != null) {
        cancelToken =
            _cancelTokens[tag] == null ? CancelToken() : _cancelTokens[tag];
        _cancelTokens[tag] = cancelToken;
      }

      Response<Map<String, dynamic>> response = await _client.request(url,
          data: data,
          queryParameters: params,
          options: options,
          cancelToken: cancelToken);
      String statusCode = response.data["statusCode"];
      if (statusCode == "0") {
        //成功
        if (successCallback != null) {
          successCallback(response.data["data"]);
        }
      } else {
        //失败
        String message = response.data["statusDesc"];
        LogUtil.v("请求服务器出错：$message");
        if (errorCallback != null) {
          errorCallback(HttpError(statusCode, message));
        }
      }
    } on DioError catch (e, s) {
      LogUtil.v("请求出错：$e/n$s");
      if (errorCallback != null && e.type != DioErrorType.CANCEL) {
        errorCallback(HttpError.dioError(e));
      }
    } catch (e, s) {
      LogUtil.v("未知异常出错：$e/n$s");
      if (errorCallback != null) {
        errorCallback(HttpError(HttpError.UNKNOWN, "网络异常，请稍后重试！"));
      }
    }
  }

  ///下载文件
  ///
  ///[url] 下载地址
  ///[savePath]  文件保存路径
  ///[onReceiveProgress]  文件保存路径
  ///[data] post 请求参数
  ///[params] url请求参数支持restful
  ///[options] 请求配置
  ///[successCallback] 请求成功回调
  ///[errorCallback] 请求失败回调
  ///[tag] 请求统一标识，用于取消网络请求
  void download({
    @required String url,
    @required savePath,
    ProgressCallback onReceiveProgress,
    Map<String, dynamic> params,
    data,
    Options options,
    HttpSuccessCallback successCallback,
    HttpFailureCallback errorCallback,
    @required String tag,
  }) async {
    //检查网络是否连接
    ConnectivityResult connectivityResult =
        await (Connectivity().checkConnectivity());
    if (connectivityResult == ConnectivityResult.none) {
      if (errorCallback != null) {
        errorCallback(HttpError(HttpError.NETWORK_ERROR, "网络异常，请稍后重试！"));
      }
      LogUtil.v("请求网络异常，请稍后重试！");
      return;
    }

    ////0代表不设置超时
    int receiveTimeout = 0;
    options ??= options == null
        ? Options(receiveTimeout: receiveTimeout)
        : options.merge(receiveTimeout: receiveTimeout);

    //设置默认值
    params = params ?? {};

    url = _restfulUrl(url, params);

    try {
      CancelToken cancelToken;
      if (tag != null) {
        cancelToken =
            _cancelTokens[tag] == null ? CancelToken() : _cancelTokens[tag];
        _cancelTokens[tag] = cancelToken;
      }

      Response response = await _client.download(url, savePath,
          onReceiveProgress: onReceiveProgress,
          queryParameters: params,
          data: data,
          options: options,
          cancelToken: cancelToken);
      //成功
      if (successCallback != null) {
        successCallback(response.data);
      }
    } on DioError catch (e, s) {
      LogUtil.v("请求出错：$e/n$s");
      if (errorCallback != null && e.type != DioErrorType.CANCEL) {
        errorCallback(HttpError.dioError(e));
      }
    } catch (e, s) {
      LogUtil.v("未知异常出错：$e/n$s");
      if (errorCallback != null) {
        errorCallback(HttpError(HttpError.UNKNOWN, "网络异常，请稍后重试！"));
      }
    }
  }

  ///上传文件
  ///
  ///[url] 网络请求地址不包含域名
  ///[data] post 请求参数
  ///[onSendProgress] 上传进度
  ///[params] url请求参数支持restful
  ///[options] 请求配置
  ///[successCallback] 请求成功回调
  ///[errorCallback] 请求失败回调
  ///[tag] 请求统一标识，用于取消网络请求
  void upload({
    @required String url,
    FormData data,
    ProgressCallback onSendProgress,
    Map<String, dynamic> params,
    Options options,
    HttpSuccessCallback successCallback,
    HttpFailureCallback errorCallback,
    @required String tag,
  }) async {
    //检查网络是否连接
    ConnectivityResult connectivityResult =
        await (Connectivity().checkConnectivity());
    if (connectivityResult == ConnectivityResult.none) {
      if (errorCallback != null) {
        errorCallback(HttpError(HttpError.NETWORK_ERROR, "网络异常，请稍后重试！"));
      }
      LogUtil.v("请求网络异常，请稍后重试！");
      return;
    }

    //设置默认值
    params = params ?? {};

    //强制 POST 请求
    options?.method = POST;

    options = options ??
        Options(
          method: POST,
        );

    url = _restfulUrl(url, params);

    try {
      CancelToken cancelToken;
      if (tag != null) {
        cancelToken =
            _cancelTokens[tag] == null ? CancelToken() : _cancelTokens[tag];
        _cancelTokens[tag] = cancelToken;
      }

      Response<Map<String, dynamic>> response = await _client.request(url,
          onSendProgress: onSendProgress,
          data: data,
          queryParameters: params,
          options: options,
          cancelToken: cancelToken);
      String statusCode = response.data["statusCode"];
      if (statusCode == "0") {
        //成功
        if (successCallback != null) {
          successCallback(response.data["data"]);
        }
      } else {
        //失败
        String message = response.data["statusDesc"];
        LogUtil.v("请求服务器出错：$message");
        if (errorCallback != null) {
          errorCallback(HttpError(statusCode, message));
        }
      }
    } on DioError catch (e, s) {
      LogUtil.v("请求出错：$e/n$s");
      if (errorCallback != null && e.type != DioErrorType.CANCEL) {
        errorCallback(HttpError.dioError(e));
      }
    } catch (e, s) {
      LogUtil.v("未知异常出错：$e/n$s");
      if (errorCallback != null) {
        errorCallback(HttpError(HttpError.UNKNOWN, "网络异常，请稍后重试！"));
      }
    }
  }

  ///GET异步网络请求
  ///
  ///[url] 网络请求地址不包含域名
  ///[params] url请求参数支持restful
  ///[options] 请求配置
  ///[tag] 请求统一标识，用于取消网络请求
  Future<T> getAsync<T>({
    @required String url,
    Map<String, dynamic> params,
    Options options,
    JsonParse<T> jsonParse,
    @required String tag,
  }) async {
    return _requestAsync(
      url: url,
      method: GET,
      params: params,
      options: options,
      jsonParse: jsonParse,
      tag: tag,
    );
  }

  ///POST 异步网络请求
  ///
  ///[url] 网络请求地址不包含域名
  ///[data] post 请求参数
  ///[params] url请求参数支持restful
  ///[options] 请求配置
  ///[tag] 请求统一标识，用于取消网络请求
  Future<T> postAsync<T>({
    @required String url,
    data,
    Map<String, dynamic> params,
    Options options,
    JsonParse<T> jsonParse,
    @required String tag,
  }) async {
    return _requestAsync(
      url: url,
      method: POST,
      data: data,
      params: params,
      options: options,
      jsonParse: jsonParse,
      tag: tag,
    );
  }

  ///统一网络请求
  ///
  ///[url] 网络请求地址不包含域名
  ///[data] post 请求参数
  ///[params] url请求参数支持restful
  ///[options] 请求配置
  ///[tag] 请求统一标识，用于取消网络请求
  Future<T> _requestAsync<T>({
    @required String url,
    String method,
    data,
    Map<String, dynamic> params,
    Options options,
    JsonParse<T> jsonParse,
    @required String tag,
  }) async {
    //检查网络是否连接
    ConnectivityResult connectivityResult =
        await (Connectivity().checkConnectivity());
    if (connectivityResult == ConnectivityResult.none) {
      LogUtil.v("请求网络异常，请稍后重试！");
      throw (HttpError(HttpError.NETWORK_ERROR, "网络异常，请稍后重试！"));
    }

    //设置默认值
    params = params ?? {};
    method = method ?? 'GET';

    options?.method = method;

    options = options ??
        Options(
          method: method,
        );

    url = _restfulUrl(url, params);

    try {
      CancelToken cancelToken;
      if (tag != null) {
        cancelToken =
            _cancelTokens[tag] == null ? CancelToken() : _cancelTokens[tag];
        _cancelTokens[tag] = cancelToken;
      }

      Response<Map<String, dynamic>> response = await _client.request(url,
          queryParameters: params,
          data: data,
          options: options,
          cancelToken: cancelToken);
      String statusCode = response.data["statusCode"];
      if (statusCode == "0") {
        //成功
        if (jsonParse != null) {
          return jsonParse(response.data["data"]);
        } else {
          return response.data["data"];
        }
      } else {
        //失败
        String message = response.data["statusDesc"];
        LogUtil.v("请求服务器出错：$message");
        //只能用 Future，外层有 try catch
        return Future.error((HttpError(statusCode, message)));
      }
    } on DioError catch (e, s) {
      LogUtil.v("请求出错：$e/n$s");
      throw (HttpError.dioError(e));
    } catch (e, s) {
      LogUtil.v("未知异常出错：$e/n$s");
      throw (HttpError(HttpError.UNKNOWN, "网络异常，请稍后重试！"));
    }
  }

  ///异步下载文件
  ///
  ///[url] 下载地址
  ///[savePath]  文件保存路径
  ///[onReceiveProgress]  文件保存路径
  ///[data] post 请求参数
  ///[params] url请求参数支持restful
  ///[options] 请求配置
  ///[tag] 请求统一标识，用于取消网络请求
  Future<Response> downloadAsync({
    @required String url,
    @required savePath,
    ProgressCallback onReceiveProgress,
    Map<String, dynamic> params,
    data,
    Options options,
    @required String tag,
  }) async {
    //检查网络是否连接
    ConnectivityResult connectivityResult =
        await (Connectivity().checkConnectivity());
    if (connectivityResult == ConnectivityResult.none) {
      LogUtil.v("请求网络异常，请稍后重试！");
      throw (HttpError(HttpError.NETWORK_ERROR, "网络异常，请稍后重试！"));
    }
    //设置下载不超时
    int receiveTimeout = 0;
    options ??= options == null
        ? Options(receiveTimeout: receiveTimeout)
        : options.merge(receiveTimeout: receiveTimeout);

    //设置默认值
    params = params ?? {};

    url = _restfulUrl(url, params);

    try {
      CancelToken cancelToken;
      if (tag != null) {
        cancelToken =
            _cancelTokens[tag] == null ? CancelToken() : _cancelTokens[tag];
        _cancelTokens[tag] = cancelToken;
      }

      return _client.download(url, savePath,
          onReceiveProgress: onReceiveProgress,
          queryParameters: params,
          data: data,
          options: options,
          cancelToken: cancelToken);
    } on DioError catch (e, s) {
      LogUtil.v("请求出错：$e/n$s");
      throw (HttpError.dioError(e));
    } catch (e, s) {
      LogUtil.v("未知异常出错：$e/n$s");
      throw (HttpError(HttpError.UNKNOWN, "网络异常，请稍后重试！"));
    }
  }

  ///上传文件
  ///
  ///[url] 网络请求地址不包含域名
  ///[data] post 请求参数
  ///[onSendProgress] 上传进度
  ///[params] url请求参数支持restful
  ///[options] 请求配置
  ///[tag] 请求统一标识，用于取消网络请求
  Future<T> uploadAsync<T>({
    @required String url,
    FormData data,
    ProgressCallback onSendProgress,
    Map<String, dynamic> params,
    Options options,
    JsonParse<T> jsonParse,
    @required String tag,
  }) async {
    //检查网络是否连接
    ConnectivityResult connectivityResult =
        await (Connectivity().checkConnectivity());
    if (connectivityResult == ConnectivityResult.none) {
      LogUtil.v("请求网络异常，请稍后重试！");
      throw (HttpError(HttpError.NETWORK_ERROR, "网络异常，请稍后重试！"));
    }

    //设置默认值
    params = params ?? {};

    //强制 POST 请求
    options?.method = POST;

    options = options ??
        Options(
          method: POST,
        );

    url = _restfulUrl(url, params);

    try {
      CancelToken cancelToken;
      if (tag != null) {
        cancelToken =
            _cancelTokens[tag] == null ? CancelToken() : _cancelTokens[tag];
        _cancelTokens[tag] = cancelToken;
      }

      Response<Map<String, dynamic>> response = await _client.request(url,
          onSendProgress: onSendProgress,
          data: data,
          queryParameters: params,
          options: options,
          cancelToken: cancelToken);

      String statusCode = response.data["statusCode"];
      if (statusCode == "0") {
        //成功
        if (jsonParse != null) {
          return jsonParse(response.data["data"]);
        } else {
          return response.data["data"];
        }
      } else {
        //失败
        String message = response.data["statusDesc"];
        LogUtil.v("请求服务器出错：$message");
        return Future.error((HttpError(statusCode, message)));
      }
    } on DioError catch (e, s) {
      LogUtil.v("请求出错：$e/n$s");
      throw (HttpError.dioError(e));
    } catch (e, s) {
      LogUtil.v("未知异常出错：$e/n$s");
      throw (HttpError(HttpError.UNKNOWN, "网络异常，请稍后重试！"));
    }
  }

  ///取消网络请求
  void cancel(String tag) {
    if (_cancelTokens.containsKey(tag)) {
      if (!_cancelTokens[tag].isCancelled) {
        _cancelTokens[tag].cancel();
      }
      _cancelTokens.remove(tag);
    }
  }

  ///restful处理
  String _restfulUrl(String url, Map<String, dynamic> params) {
    // restful 请求处理
    // /gysw/search/hist/:user_id        user_id=27
    // 最终生成 url 为     /gysw/search/hist/27
    params.forEach((key, value) {
      if (url.indexOf(key) != -1) {
        url = url.replaceAll(':$key', value.toString());
      }
    });
    return url;
  }
}

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这里内置了网络是否连接判断、取消网络请求、处理了默认的数据格式为

{
	"data":{},
	"statusCode":"0",
	"statusDesc":"02032008:用户授信未通过",
	"timestamp":1569206576392
}
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大家可根据自己的需求自行更改成自己的数据格式处理

HttpError

import 'package:dio/dio.dart';

/// @desc  网络请求错误
/// @time 2019/3/20 10:02 AM
/// @author Cheney
class HttpError {
  ///HTTP 状态码
  static const int UNAUTHORIZED = 401;
  static const int FORBIDDEN = 403;
  static const int NOT_FOUND = 404;
  static const int REQUEST_TIMEOUT = 408;
  static const int INTERNAL_SERVER_ERROR = 500;
  static const int BAD_GATEWAY = 502;
  static const int SERVICE_UNAVAILABLE = 503;
  static const int GATEWAY_TIMEOUT = 504;

  ///未知错误
  static const String UNKNOWN = "UNKNOWN";

  ///解析错误
  static const String PARSE_ERROR = "PARSE_ERROR";

  ///网络错误
  static const String NETWORK_ERROR = "NETWORK_ERROR";

  ///协议错误
  static const String HTTP_ERROR = "HTTP_ERROR";

  ///证书错误
  static const String SSL_ERROR = "SSL_ERROR";

  ///连接超时
  static const String CONNECT_TIMEOUT = "CONNECT_TIMEOUT";

  ///响应超时
  static const String RECEIVE_TIMEOUT = "RECEIVE_TIMEOUT";

  ///发送超时
  static const String SEND_TIMEOUT = "SEND_TIMEOUT";

  ///网络请求取消
  static const String CANCEL = "CANCEL";

  String code;

  String message;

  HttpError(this.code, this.message);

  HttpError.dioError(DioError error) {
    message = error.message;
    switch (error.type) {
      case DioErrorType.CONNECT_TIMEOUT:
        code = CONNECT_TIMEOUT;
        message = "网络连接超时，请检查网络设置";
        break;
      case DioErrorType.RECEIVE_TIMEOUT:
        code = RECEIVE_TIMEOUT;
        message = "服务器异常，请稍后重试！";
        break;
      case DioErrorType.SEND_TIMEOUT:
        code = SEND_TIMEOUT;
        message = "网络连接超时，请检查网络设置";
        break;
      case DioErrorType.RESPONSE:
        code = HTTP_ERROR;
        message = "服务器异常，请稍后重试！";
        break;
      case DioErrorType.CANCEL:
        code = CANCEL;
        message = "请求已被取消，请重新请求";
        break;
      case DioErrorType.DEFAULT:
        code = UNKNOWN;
        message = "网络异常，请稍后重试！";
        break;
    }
  }

  @override
  String toString() {
    return 'HttpError{code: $code, message: $message}';
  }
}

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这里设置的多种错误的描述，大家可根据需求自行修改

LogInterceptor

import 'package:dio/dio.dart';
import 'package:flutter_common_utils/log_util.dart';

void log2Console(Object object) {
  LogUtil.v(object);
}

/// @desc  自定义日志拦截器
///@time 2019/3/18 9:15 AM
/// @author Cheney
class LogInterceptor extends Interceptor {
  LogInterceptor({
    this.request = true,
    this.requestHeader = true,
    this.requestBody = false,
    this.responseHeader = true,
    this.responseBody = false,
    this.error = true,
    this.logPrint = log2Console,
  });

  /// Print request [Options]
  bool request;

  /// Print request header [Options.headers]
  bool requestHeader;

  /// Print request data [Options.data]
  bool requestBody;

  /// Print [Response.data]
  bool responseBody;

  /// Print [Response.headers]
  bool responseHeader;

  /// Print error message
  bool error;

  /// Log printer; defaults print log to console.
  /// In flutter, you'd better use debugPrint.
  /// you can also write log in a file, for example:
  ///```dart
  ///  var file=File("./log.txt");
  ///  var sink=file.openWrite();
  ///  dio.interceptors.add(LogInterceptor(logPrint: sink.writeln));
  ///  ...
  ///  await sink.close();
  ///```
  void Function(Object object) logPrint;

  @override
  Future onRequest(RequestOptions options) async {
    logPrint('*** Request ***');
    printKV('uri', options.uri);

    if (request) {
      printKV('method', options.method);
      printKV('responseType', options.responseType?.toString());
      printKV('followRedirects', options.followRedirects);
      printKV('connectTimeout', options.connectTimeout);
      printKV('receiveTimeout', options.receiveTimeout);
      printKV('extra', options.extra);
    }
    if (requestHeader) {
      logPrint('headers:');
      options.headers.forEach((key, v) => printKV(" $key", v));
    }
    if (requestBody) {
      logPrint("data:");
      printAll(options.data);
    }
    logPrint("");
  }

  @override
  Future onError(DioError err) async {
    if (error) {
      logPrint('*** DioError ***:');
      logPrint("uri: ${err.request.uri}");
      logPrint("$err");
      if (err.response != null) {
        _printResponse(err.response);
      }
      logPrint("");
    }
  }

  @override
  Future onResponse(Response response) async {
    logPrint("*** Response ***");
    _printResponse(response);
  }

  void _printResponse(Response response) {
    printKV('uri', response.request?.uri);
    if (responseHeader) {
      printKV('statusCode', response.statusCode);
      if (response.isRedirect == true) {
        printKV('redirect', response.realUri);
      }
      if (response.headers != null) {
        logPrint("headers:");
        response.headers.forEach((key, v) => printKV(" $key", v.join(",")));
      }
    }
    if (responseBody) {
      logPrint("Response Text:");
      printAll(response.toString());
    }
    logPrint("");
  }

  printKV(String key, Object v) {
    logPrint('$key: $v');
  }

  printAll(msg) {
    msg.toString().split("/n").forEach(logPrint);
  }
}

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这里默认使用 LogUtl 输出日志，大家可根据需要换成自己的日志输出工具类

使用示例

Step1：初始化

//初始化 Http，
  HttpManager().init(
    baseUrl: Api.getBaseUrl(),
    interceptors: [
      HeaderInterceptor(),
      LogInterceptor(),
    ],
  );
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Step2：创建网络请求

///同步回调模式
///get 网络请求
void _get(){
   HttpManager().get(
      url: "/app/info",
      params: {"iouCode": iouCode},
      successCallback: (data) {
        
      },
      errorCallback: (HttpError error) {
       
      },
      tag: "tag",
    );
}
///post 网络请求
void _post(){
     HttpManager().post(
      url: "/app/info",
      data: {"iouCode": iouCode},
      successCallback: (data) {
        
      },
      errorCallback: (HttpError error) {
        
      },
      tag: "tag",
    );
}

///下载文件
void _download(){
     HttpManager().download(
      url: "/app/download",
      savePath: "/savePath",
      onReceiveProgress: (int count, int total) {
      },
      successCallback: (data) {
        
      },
      errorCallback: (HttpError error) {
        
      },
      tag: tag,
    );
}

///上传文件
void _upload() async{
FormData data = FormData.fromMap({
        "file": await MultipartFile.fromFile(path, filename: "$photoTime"),
      });
    HttpManager().upload(
        url: "/app/upload",
        data: data,
        tag: "tag",
        successCallback: (data) {
          
        },
        errorCallback: (HttpError error) {
          
        },
      );
}


///异步模式
///get 请求
void _getAysnc() async{
     String timestamp =
        await HttpManager().getAsync(url: "/app/info", tag: "syncTime");
}

///post 请求
void _postAysnc() async{
   await HttpManager().postAsync(
        url: "app/info",
        tag: "tag",
        data: {
          'bannerTypes': ["wealthBanner"],
        },
        jsonParse: (json) => Pager(json, (data) => ImageAd(data)))
}

///下载文件
void _downloadAsync() async{
    await HttpManager().downloadAsync(
      url: "/app/download",
      savePath: "/savePath",
      onReceiveProgress: (int count, int total) {
      },
      tag: "tag",
    );
}

///上传文件
void _uploadAsync() async{
FormData data = FormData.fromMap({
        "file": await MultipartFile.fromFile(path, filename: "$photoTime"),
      });
  await  HttpManager().uploadAsync(
        url: "/app/upload",
        data: data,
        tag: "tag",
       
      );
}
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原文 https://juejin.im/post/5e6dcfc7e51d45270411837d

正文到此结束