Flutter网络请求Dio库的使用及封装详解

dev_dependencies:
  flutter_test:
    sdk: flutter 
  # The "flutter_lints" package below contains a set of recommended lints to
  # encourage good coding practices. The lint set provided by the package is
  # activated in the `analysis_options.yaml` file located at the root of your
  # package. See that file for information about deactivating specific lint
  # rules and activating additional ones.
  flutter_lints: ^1.0.0
  # 数据请求
  dio: ^4.0.4

import 'package:dio/dio.dart';
/// dio网络请求配置表 自定义
class DioConfig {
  static const baseURL = 'http://117.34.71.31:8081/paas-admin'; //域名
  static const timeout = 10000; //超时时间
} 
// 网络请求工具类
class DioRequest {
  late Dio dio;
  static DioRequest? _instance;
  /// 构造函数
  DioRequest() {
    dio = Dio();
    dio.options = BaseOptions(
        baseUrl: DioConfig.baseURL,
        connectTimeout: DioConfig.timeout,
        sendTimeout: DioConfig.timeout,
        receiveTimeout: DioConfig.timeout,
        contentType: 'application/json; charset=utf-8',
        headers: {});
    /// 请求拦截器 and 响应拦截机 and 错误处理
    dio.interceptors.add(InterceptorsWrapper(onRequest: (options, handler) {
      print("\n================== 请求数据 ==========================");
      print("url = ${options.uri.toString()}");
      print("headers = ${options.headers}");
      print("params = ${options.data}");
      return handler.next(options);
    }, onResponse: (response, handler) {
      print("\n================== 响应数据 ==========================");
      print("code = ${response.statusCode}");
      print("data = ${response.data}");
      print("\n");
      handler.next(response);
    }, onError: (DioError e, handler) {
      print("\n================== 错误响应数据 ======================");
      print("type = ${e.type}");
      print("message = ${e.message}");
      print("\n");
      return handler.next(e);
    }));
  }
  static DioRequest getInstance() {
    return _instance ??= DioRequest();
  }
}

import 'dart:convert';

import 'package:cyber_security/utils/http.dart';

class LoginService {
  /// 获取用户数据中心列表
  static Future<List> getDataCenter() async {
    var response = await DioRequest.getInstance().dio.get('/getDataCenter');
    var data = jsonDecode(response.toString());
    return data['dataCenterList'];
  }

  /// 登录接口
  static login(value) async {
    var response = await DioRequest.getInstance()
        .dio
        .post('/sys/login', queryParameters: value);
    var data = jsonDecode(response.toString()); 
    /// 对返回的身份凭证全局持久化存储
    return data['key'];
  }

  /// 获取权限列表
  static menuNav() async {
    var response = await DioRequest.getInstance().dio.get('/sys/menu/nav');
    var data = jsonDecode(response.toString());
    return data['key'];
  }
}

@override
  void initState() {
    // TODO: implement initState
    super.initState();
    /// 请求用户数据中心数据
    LoginService.getDataCenter().then((value) {
      setState(() {
        _dataCenterList = value;
      });
    });
  }