Flutter-網絡請求

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：

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

導入

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

void _httpClient() async{
      //创建一个HttpClient
      HttpClient httpClient = new HttpClient();
      //携带参数的请求
      /*Uri uri=Uri(scheme: "https", host: "flutterchina.club", queryParameters: {
        "userName":"chen",
        "password":"123456"
      });*/
      var url = 'http://47.100.106.80:8080/Test/all';
      //打开Http连接，设置请求头
      HttpClientRequest request = await httpClient.getUrl(Uri.parse(url));
      //设置请求的 header
      request.headers.add("user-agent", "test");
      request.headers.add("Authorization", "LKSJDLFJSDLKJSLKklsdj");
      //等待连接服务器
      HttpClientResponse response = await request.close();
      //读取响应内容
      if (response.statusCode == HttpStatus.ok) {
        var data = await response.transform(Utf8Decoder()).join();
        print(data);
      }
      //断开连接
      //httpClient.close();
    }

第三方HTTP

添加依賴

http: ^0.11.0

導入包

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

get請求

//异步加载数据
    void _getRequest() async {
      //下面为具体网址，需要自己修改
      String url = "http://47.100.106.80:8080/Test/all";
      var client = http.Client();
      http.Response response = await client.get(url);
      setState(() {
        final data = json.encode(response.body);
        print('data:'+data);
      });
    }

    //初始化状态
    @override
    void initState() {
      super.initState();
      _getRequest();
    }

post

//异步加载数据
    void _postRequest() async {
      String url = "http://47.100.106.80:8080/Test/add";
      var client = http.Client();
      var params = Map<String,String>();
      params['name'] = '測試數據';

      http.Response response = await client.post(url,body:params);
      setState(() {
        final data = json.encode(response.body);
        print(data);
      });
    }

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...

添加依賴

dependencies:
  dio: ^1.0.9

導入

import 'package:dio/dio.dart';

get請求

void getRequest() async {
      Dio dio = new Dio();
      var response = await dio.get("http://47.100.106.80:8080/Test/all");
      final data = response.data.toString();
      print(data);
    }

post請求

void postRequest() async {
      var dio = new Dio();
      var response = await dio.post("http://47.100.106.80:8080/Test/add", data:{"name":"name1","account":"測試數據212312"});
      final data = response.data.toString();
      print(response);
      print(data);
    }

參考：https://www.jianshu.com/p/3080e0b81cf4

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

 

jsontobean.png

• step 3：输入实体类名及 json 格式的数据

   

  

  format.png

• 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 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);
    }
  }
}