Flutter 网络请求框架封装详解

2019-12-12 00:14:47

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Flutter 请求网络的三种方式

flutter 请求网络的方式有三种，分别是 Dart 原生的网络请求 HttpClient、第三方网络请求 http以及 Flutter 中的 Dio。我们可以比较一下这三种网络请求方式，然后封装为我们方便请求网络的工具类。

Dart 原生的网络请求 HttpClient

实现 Dart 获取网络数据的请求，一般我们需要以下几个步骤：

step 1：原生的网络请求时不需要修改 pubspec.yaml 文件的，我们只需要在使用的地方引入所需包就可以了

import 'dart:convert';import 'dart:io';

step 2：创建一个HttpClient

HttpClient httpClient = new HttpClient();

step 3: 打开Http连接，设置请求头

HttpClientRequest request = await httpClient.getUrl(uri);

在这一步中，我们可以设置人意的的请求方法，比如 Get 请求、Post 请求、Delete 请求。

例如：携带参数的请求

Uri uri=Uri(scheme: "https", host: "flutterchina.club", queryParameters: {  "userName":"chen",  "password":"123456" });

例如：设置请求的 header

request.headers.add("user-agent", "test");request.headers.add("Authorization", "LKSJDLFJSDLKJSLKklsdj");

step 4: 等待连接服务器

HttpClientResponse response = await request.close();

step 5: 读取响应内容

if (response.statusCode == HttpStatus.ok) {   _content = await response.transform(Utf8Decoder()).join();}

step 6: 断开连接

httpClient.close();

以上的步骤是 dart 简单获取网络的方式，我们从上面可以看到，通过 HttpClient 发起网络请求时比较麻烦的，很多都要我们亲手处理，还有 Cookie 的管理也是比较麻烦的。

库 http step

1：pubspec.yaml 添加依赖

http: '>=0.11.3+12'

step 2: 在使用的地方导包

import 'package:http/http.dart' as http;

step 3：发起请求

Get 请求

void getRequest() async {  var client = http.Client();  http.Response response = await client.get(url_2);  _content = response.body; }

Post 请求

 void postRequest() async {  var params = Map<String, String>();  params["username"] = "hellonews";  params["password"] = "123456";  var client = http.Client();  var response = await client.post(url_post, body: params);  _content = response.body; }

相对比 Dart 原生的网络请求，第三方库 http 的网络请求方式是要方便好多，写起来也是挺爽的。

Flutter 发布的 dio

Dio 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...

step 1：pubspec.yaml 添加依赖

dependencies: dio: ^1.0.9

step 2：导入引用包

import 'package:dio/dio.dart';

step 3：发起网络请求

Get 请求

void getRequest() async {  Dio dio = new Dio();  var response = await dio.get("/test?id=12&name=chen");  _content = response.data.toString(); }

对于 query 参数，我们可以通过对象来进行传递，上面的代码等同于：

void getRequest() async {  Dio dio = new Dio();  var response = await dio.get("/test"，data:{"id":12,"name":"chen"});  _content = response.data.toString(); }

Post 请求

 void postRequest() async {  var dio = new Dio();  var response = await dio.post(url_post, data:{"id":12,"name":"wendu"});  _content = response.data.toString(); }

Dio 网络请求框架封装

日志信息拦截

Dio 和 okhttp 一样，都会有一个请求拦截器和响应拦截器，通过拦截器，我们可以在请求之前或响应之后做一些同意的预处理。例如我们发起请求前查看我们请求的参数和头部，响应的时候，我们可以查看返回来的数据。

  Dio dio = new Dio();  // 添加拦截器  if (Config.DEBUG) {   dio.interceptors.add(InterceptorsWrapper(     onRequest: (RequestOptions options){      print("/n================== 请求数据 ==========================");      print("url = ${options.uri.toString()}");      print("headers = ${options.headers}");      print("params = ${options.data}");     },     onResponse: (Response response){      print("/n================== 响应数据 ==========================");      print("code = ${response.statusCode}");      print("data = ${response.data}");      print("/n");     },     onError: (DioError e){      print("/n================== 错误响应数据 ======================");      print("type = ${e.type}");      print("message = ${e.message}");      print("stackTrace = ${e.stackTrace}");      print("/n");     }   ));  }

如果我们想要移除拦截器，那么我们可以将其设置为 null

dio.interceptor.request.onSend=null;dio.interceptor.response.onSuccess=null;dio.interceptor.response.onError=null;

token 添加

  // 头部添加 token 验证  headers["Authorization"] = "token lskjdlklsjkdklsjd333";  option.headers = headers;  ///超时  option.connectTimeout = 15000;  try {   Response response = await dio.request(url, data: params, options: option);  } on DioError catch (e) {   // 请求错误处理  }

自动生成 dart 的 json 实体类插件 FlutterJsonBeanFactory

在 Android 开发中，有 GsonFormat 这个插件来讲 json 数据自动转化成 Bean；那么在 Flutter 中也有类似的插件可以生产序列化的实体类的插件：FlutterJsonBeanFactory

step 1：下载插件 FlutterJsonBeanFactory，安装完成后重启

Setting -> Plugins -> Browse Respositories 中搜索 FlutterJsonBeanFactory

step 2：创建实体类，在指定目录下：

New -> dart bean class File from JSON

step 3：输入实体类名及 json 格式的数据

step 4：最后生成的实体类：LoginEntity

class LoginEntity {	String easemobpassword;	String username;	LoginEntity({this.easemobpassword, this.username});	LoginEntity.fromJson(Map<String, dynamic> json) {		easemobpassword = json['easemobPassword'];		username = json['username'];	}	Map<String, dynamic> toJson() {		final Map<String, dynamic> data = new Map<String, dynamic>();		data['easemobPassword'] = this.easemobpassword;		data['username'] = this.username;		return data;	}}

请求错误处理

 Response response;  try {   response = await dio.request(url, data: params, options: option);  } on DioError catch (e) {   // 请求错误处理   Response errorResponse;   if (e.response != null) {    errorResponse = e.response;   } else {    errorResponse = new Response(statusCode: 666);   }   if (e.type == DioErrorType.CONNECT_TIMEOUT) {    errorResponse.statusCode = Code.NETWORK_TIMEOUT;   }   if (Config.DEBUG) {    print('请求异常: ' + e.toString());    print('请求异常 url: ' + url);   }   return new ResultData(Code.errorHandleFunction(errorResponse.statusCode, e.message, noTip), false, errorResponse.statusCode);  }

其中 ResultData 是网络结果处理的实体类

/** * 网络结果数据 * Created by chenjianrun * Date: 2018-07-16 */class ResultData { var data; bool result; int code; var headers; ResultData(this.data, this.result, this.code, {this.headers});}

Code 是处理网络错误的编码，并将错误结果通过 eventbus 发送出去，一般我们可以在 main_pager 中注册监听这个事件。

///网络请求错误编码class Code { ///网络错误 static const NETWORK_ERROR = -1; ///网络超时 static const NETWORK_TIMEOUT = -2; ///网络返回数据格式化一次 static const NETWORK_JSON_EXCEPTION = -3; static const SUCCESS = 200; static final EventBus eventBus = new EventBus(); static errorHandleFunction(code, message, noTip) {  if(noTip) {   return message;  }  eventBus.fire(new HttpErrorEvent(code, message));  return message; }}

完成的网络请求类：HttpRequest

import 'dart:io';import 'package:dio/dio.dart';import 'package:private_tutor/common/SpUtils.dart';import 'package:connectivity/connectivity.dart';import 'dart:collection';import 'package:private_tutor/common/config/Config.dart';import 'package:private_tutor/net/ResultCode.dart';import 'package:private_tutor/net/ResultData.dart';///http请求管理类，可单独抽取出来class HttpRequest { static String _baseUrl; static const CONTENT_TYPE_JSON = "application/json"; static const CONTENT_TYPE_FORM = "application/x-www-form-urlencoded"; static Map optionParams = {  "timeoutMs": 15000,  "token": null,  "authorizationCode": null, }; static setBaseUrl(String baseUrl){  _baseUrl = baseUrl; } static get(url,param) async{  return await request(_baseUrl+url, param, null, new Options(method:"GET")); } static post(url,param) async{  return await request(_baseUrl+url, param, {"Accept": 'application/vnd.github.VERSION.full+json'}, new Options(method: 'POST')); } static delete(url,param) async{  return await request(_baseUrl+url, param, null, new Options(method: 'DELETE')); } static put(url,param) async{  return await request(_baseUrl+url, param, null, new Options(method: "PUT", contentType: ContentType.text)); } ///发起网络请求 ///[ url] 请求url ///[ params] 请求参数 ///[ header] 外加头 ///[ option] 配置 static request(url, params, Map<String, String> header, Options option, {noTip = false}) async {  //没有网络  var connectivityResult = await (new Connectivity().checkConnectivity());  if (connectivityResult == ConnectivityResult.none) {   return new ResultData(Code.errorHandleFunction(Code.NETWORK_ERROR, "", noTip), false, Code.NETWORK_ERROR);  }  Map<String, String> headers = new HashMap();  if (header != null) {   headers.addAll(header);  }  //授权码  if (optionParams["authorizationCode"] == null) {   var authorizationCode = await getAuthorization();   if (authorizationCode != null) {    optionParams["authorizationCode"] = authorizationCode;   }  }  headers["Authorization"] = optionParams["authorizationCode"];  // 设置 baseUrl    if (option != null) {   option.headers = headers;  } else{   option = new Options(method: "get");   option.headers = headers;  }  ///超时  option.connectTimeout = 15000;  Dio dio = new Dio();  // 添加拦截器  if (Config.DEBUG) {   dio.interceptors.add(InterceptorsWrapper(     onRequest: (RequestOptions options){      print("/n================== 请求数据 ==========================");      print("url = ${options.uri.toString()}");      print("headers = ${options.headers}");      print("params = ${options.data}");     },     onResponse: (Response response){      print("/n================== 响应数据 ==========================");      print("code = ${response.statusCode}");      print("data = ${response.data}");      print("/n");     },     onError: (DioError e){      print("/n================== 错误响应数据 ======================");      print("type = ${e.type}");      print("message = ${e.message}");      print("stackTrace = ${e.stackTrace}");      print("/n");     }   ));  }  Response response;  try {   response = await dio.request(url, data: params, options: option);  } on DioError catch (e) {   // 请求错误处理   Response errorResponse;   if (e.response != null) {    errorResponse = e.response;   } else {    errorResponse = new Response(statusCode: 666);   }   if (e.type == DioErrorType.CONNECT_TIMEOUT) {    errorResponse.statusCode = Code.NETWORK_TIMEOUT;   }   if (Config.DEBUG) {    print('请求异常: ' + e.toString());    print('请求异常 url: ' + url);   }   return new ResultData(Code.errorHandleFunction(errorResponse.statusCode, e.message, noTip), false, errorResponse.statusCode);  }  try {   if (option.contentType != null && option.contentType.primaryType == "text") {    return new ResultData(response.data, true, Code.SUCCESS);   } else {    var responseJson = response.data;    if (response.statusCode == 201 && responseJson["token"] != null) {     optionParams["authorizationCode"] = 'token ' + responseJson["token"];     await SpUtils.save(Config.TOKEN_KEY, optionParams["authorizationCode"]);    }   }   if (response.statusCode == 200 || response.statusCode == 201) {    return ResultData(response.data, true, Code.SUCCESS, headers: response.headers);   }  } catch (e) {   print(e.toString() + url);   return ResultData(response.data, false, response.statusCode, headers: response.headers);  }  return new ResultData(Code.errorHandleFunction(response.statusCode, "", noTip), false, response.statusCode); } ///清除授权 static clearAuthorization() {  optionParams["authorizationCode"] = null;  SpUtils.remove(Config.TOKEN_KEY); } ///获取授权token static getAuthorization() async {  String token = await SpUtils.get(Config.TOKEN_KEY);  if (token == null) {   String basic = await SpUtils.get(Config.USER_BASIC_CODE);   if (basic == null) {    //提示输入账号密码   } else {    //通过 basic 去获取token，获取到设置，返回token    return "Basic $basic";   }  } else {   optionParams["authorizationCode"] = token;   return token;  } }}

使用示例

/// 登录 modelclass LoginModel{  // 手机号码登录 static phoneLogin(String phone,String verifyCode) async{  ResultData response = await HttpRequest.post(Address.phoneLogin, {"phoneNum" : phone,"captcha":verifyCode});  if(response != null && response.result){    PhoneLoginEntity phoneLoginEntity = PhoneLoginEntity.fromJson(json.decode(response.data));    return new DataResult(phoneLoginEntity, true);  }else{   return new DataResult(null, false);  } }  // 获取验证码 static getVerifyCode(String phone) async{  ResultData response = await HttpRequest.get("${Address.getVerifyCode}?phone=${phone}", null);//  var response = await HttpRequest.get(Address.getVerifyCode, {"phone":phone});  if(response != null && response.result){   VerifyCodeEntity entity = VerifyCodeEntity.fromJson(response.data);   return new DataResult(entity, true);  }else{   return new DataResult(null, false);  } }}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持武林网。

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