这篇文章主要介绍了Flutter 网络请求框架封装详解，小编觉得挺不错的，现在分享给大家，也给大家做个参考。一起跟随小编过来看看吧
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(); 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 json) { easemobpassword = json['easemobPassword']; username = json['username']; } Map toJson() { final Map data = new Map(); 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 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 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 $basic"; } } else { optionParams["authorizationCode"] = token; return token; } } } 使用示例
/// 登录 model class LoginModel{ // 手机号码登录 static phoneLogin(String phone,String verifyCode) async{ ResultData response = await HttpRequest.post(Address.phoneLogin, {"phoneNum" : phone,"captcha":verifyCode}); if(response != null && response.result){ PhoneLoginEntity phoneLoginEntity = PhoneLoginEntity.fromJson(json.decode(response.data)); return new DataResult(phoneLoginEntity, true); }else{ return new DataResult(null, false); } } // 获取验证码 static getVerifyCode(String phone) async{ ResultData response = await HttpRequest.get("${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Flutter 网络请求框架封装详解的详细内容，更多请关注0133技术站其它相关文章！
