Flutter应用连接API遇SocketException连接超时错误，求解决方案

问题描述 #

我尝试将Flutter应用与API连接，编写了如下GET请求代码：

Future<void> fetchData() async {
        final String apiUrl = 'http://192.168.100.90:4002/booking/getall';
        try {
          // Making GET request
          final response = await http.get(Uri.parse(apiUrl));
          print(response.statusCode);
          // Decoding response
          if (response.statusCode == 200) {
            // If the server returns a 200 OK response,
            // parse the JSON
            final Map<String, dynamic> responseData = json.decode(response.body);

            // Process the data here if needed
            print(responseData);
          } else {
            // If the server did not return a 200 OK response,
            // throw an exception
            throw Exception('Failed to load data');
          }
        } catch (e) {
          // Error handling
          print('Error: $e');
          throw e;
        }
      }

运行时出现以下错误：

I/flutter ( 2707): Error: ClientException with SocketException: Connection timed out (OS Error: Connection timed out, errno = 110), address = 192.168.100.90, port = 48130, uri=http://192.168.100.90:4002/booking/getall
E/flutter ( 2707): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: ClientException with SocketException: Connection timed out (OS Error: Connection timed out, errno = 110), address = 192.168.100.90, port = 48130, uri=http://192.168.100.90:4002/booking/getall

解决方案 #

• 检查网络连通性

  1. 确认Flutter设备（模拟器/真机）与API服务器处于同一局域网（如同一WiFi）
  2. 在设备浏览器中直接访问http://192.168.100.90:4002/booking/getall，若无法访问，问题出在API服务器而非Flutter代码

• 验证API服务器状态

  1. 确认服务器程序正在运行，且监听端口为4002
  2. 检查服务器防火墙/安全组设置，确保4002端口允许局域网设备访问
  3. Android模拟器访问本地服务器时，需将192.168.100.90替换为10.0.2.2（模拟器的本地回环映射地址）；iOS模拟器可直接使用局域网IP或localhost

• 设置请求超时
  主动添加超时限制，避免无限等待：

  final response = await http.get(Uri.parse(apiUrl)).timeout(
    const Duration(seconds: 10),
    onTimeout: () {
      throw Exception('请求超时，请检查网络或服务器');
    },
  );
  

• 配置网络权限
  Android端：在android/app/src/main/AndroidManifest.xml中添加权限

  <uses-permission android:name="android.permission.INTERNET" />
  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
  

  iOS端：在ios/Runner/Info.plist中添加HTTP请求允许配置（正式环境建议改用HTTPS并配置ATS规则）

  <key>NSAppTransportSecurity</key>
  <dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
  </dict>
  

内容的提问来源于stack exchange，提问作者satyam gupta