如何在Flutter真机中调用本地Spring Boot API？连接失败排查

我开发了Spring Boot Web应用，提供给Flutter移动端调用的API，Spring Boot运行在本地，示例地址为http://127.0.0.1:8086/assessmentportal/authenticate/verifyemail/reset-password-otp。尝试在Flutter真机上调用API时失败，已确保手机和电脑处于同一网络（笔记本以太网+热点Wi-Fi），但问题未解决。

Flutter端API调用代码 #

class API {
  final sendEmailOTPUrl =
      "http://127.0.0.1:8086/assessmentportal/authenticate/verifyemail/sendotp";
  final verifyEmailOTPUrl =
      "http://127.0.0.1:8086/assessmentportal/authenticate/verifyemail/verify-otp";

  final Dio _dio = Dio();
  Future<Map<String, String>> sendEmailVerificationOTP(
      {required String? email}) async {
    Map<String, String> data = {"email": "$email"};
    Response response = await _dio.post(sendEmailOTPUrl, data: data);
    log("Response obtained: $response");
    Map<String, String> result = jsonDecode(response.data);
    return result;
  }

  Future<Map<String, String>> verifyEmailVerificationOTP(
      {required String? email, required String? otp}) async {
    Map<String, dynamic> data = {"email": email, "otp": int.parse(otp!)};
    Response response = await _dio.post(verifyEmailOTPUrl, data: data);
    Map<String, String> result = jsonDecode(response.data);
    return result;
  }
}

运行错误日志 #

E/flutter ( 3127): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: DioError [DioErrorType.other]: SocketException: Connection refused (OS Error: Connection refused, errno = 111), address = 127.0.0.1, port = 34222
E/flutter ( 3127): Source stack:
E/flutter ( 3127): #0      DioMixin.fetch (package:dio/src/dio_mixin.dart:488:35)
E/flutter ( 3127): #1      DioMixin.request (package:dio/src/dio_mixin.dart:483:12)
E/flutter ( 3127): #2      DioMixin.post (package:dio/src/dio_mixin.dart:97:12)
E/flutter ( 3127): #3      API.sendEmailVerificationOTP (package:assessmentportal/NewtworkUtil/API.dart:16:36)
E/flutter ( 3127): #4      _RegisterScreenState.build.<anonymous closure>.<anonymous closure> (package:assessmentportal/Register%20and%20Login/RegisterScren.dart:80:45)
E/flutter ( 3127): #5      _InkResponseState.handleTap (package:flutter/src/material/ink_well.dart:1072:21)
E/flutter ( 3127): #6      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:253:24)
E/flutter ( 3127): #7      TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:627:11)
E/flutter ( 3127): #8      BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:306:5)
E/flutter ( 3127): #9      BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:239:7)
E/flutter ( 3127): #10     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:615:9)
E/flutter ( 3127): #11     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:98:12)
E/flutter ( 3127): #12     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:143:9)
E/flutter ( 3127): #13     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:617:13)
E/flutter ( 3127): #14     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:141:18)
E/flutter ( 3127): #15     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:127:7)
E/flutter ( 3127): #16     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:460:19)
E/flutter ( 3127): #17     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:440:22)
E/flutter ( 3127): #18     RendererBinding.dispatchEvent (package:flutter/src/rendering/binding.dart:337:11)
E/flutter ( 3127): #19     GestureBinding._handlePointerEventImmediately (package:flutter/src/gestures/binding.dart:395:7)
E/flutter ( 3127): #20     GestureBinding.handlePointerEvent (package:flutter/src/gestures/binding.dart:357:5)
E/flutter ( 3127): #21     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:314:7)
E/flutter ( 3127): #22     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:295:7)
E/flutter ( 3127): #23     _invoke1 (dart:ui/hooks.dart:167:13)
E/flutter ( 3127): #24     PlatformDispatcher._dispatchPointerDataPacket (dart:ui/platform_dispatcher.dart:341:7)
E/flutter ( 3127): #25     _dispatchPointerDataPacket (dart:ui/hooks.dart:94:31)
E/flutter ( 3127): 
E/flutter ( 3127): #0      DioMixin.fetch.<anonymous closure> (package:dio/src/dio_mixin.dart:643:7)
E/flutter ( 3127): #1      _RootZone.runBinary (dart:async/zone.dart:1658:54)
E/flutter ( 3127): #2      _FutureListener.handleError (dart:async/future_impl.dart:162:22)
E/flutter ( 3127): #3      Future._propagateToListeners.handleError (dart:async/future_impl.dart:778:47)
E/flutter ( 3127): #4      Future._propagateToListeners (dart:async/future_impl.dart:799:13)
E/flutter ( 3127): #5      Future._completeError (dart:async/future_impl.dart:574:5)
E/flutter ( 3127): #6      _SyncCompleter._completeError (dart:async/future_impl.dart:51:12)
E/flutter ( 3127): #7      _Completer.completeError (dart:async/future_impl.dart:23:5)
E/flutter ( 3127): #8      Future.any.onError (dart:async/future.dart:617:45)
E/flutter ( 3127): #9      _RootZone.runBinary (dart:async/zone.dart:1658:54)
E/flutter ( 3127): #10     _FutureListener.handleError (dart:async/future_impl.dart:162:22)
E/flutter ( 3127): #11     Future._propagateToListeners.handleError (dart:async/future_impl.dart:778:47)
E/flutter ( 3127): #12     Future._propagateToListeners (dart:async/future_impl.dart:799:13)
E/flutter ( 3127): #13     Future._completeError (dart:async/future_impl.dart:574:5)
E/flutter ( 3127): #14     Future._asyncCompleteError.<anonymous closure> (dart:async/future_impl.dart:665:7)
E/flutter ( 3127): #15     _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
E/flutter ( 3127): #16     _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
E/flutter ( 3127): 
I/ViewRootImpl@aa5f3e2[MainActivity]( 3127): MSG_WINDOW_FOCUS_CHANGED 0 1

错误原因分析 #

• 代码中使用127.0.0.1作为API地址，在真机上这个地址指向手机自身，而非运行Spring Boot的电脑，导致连接拒绝。
• 错误日志中的端口34222是手机发起请求的本地端口，不是Spring Boot的8086端口，属于正常现象，核心问题还是地址指向错误。

解决方法 #

1. 获取电脑局域网IP地址 #

• Windows：打开命令提示符，输入ipconfig，找到当前热点Wi-Fi对应的适配器的IPv4地址（格式如192.168.x.x）。
• macOS/Linux：打开终端，输入ifconfig或ip addr，找到对应网络接口的IP地址。

2. 修改Flutter中的API地址 #

将代码中的127.0.0.1替换为电脑的局域网IP：

class API {
  // 替换为你的电脑局域网IP
  final String baseUrl = "http://192.168.1.100:8086/assessmentportal/authenticate/verifyemail";
  final sendEmailOTPUrl = "$baseUrl/sendotp";
  final verifyEmailOTPUrl = "$baseUrl/verify-otp";

  // 其余代码保持不变
}

3. 配置Spring Boot允许外部访问 #

在application.properties或application.yml中，确保应用绑定到所有IP：

server.address=0.0.0.0
server.port=8086

4. 开放电脑防火墙8086端口 #

• Windows：进入防火墙设置，添加入站规则，允许8086端口的TCP连接。
• macOS/Linux：使用ufw allow 8086/tcp命令开放端口。

5. 验证网络连通性 #

在手机浏览器中访问http://[电脑IP]:8086/assessmentportal/authenticate/verifyemail/reset-password-otp，如果能正常响应，再重新运行Flutter应用测试API调用。

内容的提问来源于stack exchange，提问作者ayush