Docker化Spring Boot应用连接外部MQTT服务器失败求助

我有一个作为MQTT客户端的Spring应用，本地运行时连接tcp://localhost:1883（Windows服务形式安装的Mosquitto）一切正常，但Docker化后，即使把连接地址换成host.docker.internal:1883，依然报错org.eclipse.paho.client.mqttv3.MqttException: Unable to connect to server。

相关配置 #

docker-compose配置 #

mqtt:
  build:
    context: MQTT
    dockerfile: Dockerfile
  environment:
    SPRING_DATASOURCE_URL: jdbc:mysql://mysql:3306/mt_db
    SPRING_DATASOURCE_USERNAME: root
    mqttUrl: tcp://host.docker.internal:1883
  ports:
    - 8082:8082
  depends_on:
    - mysql
  networks:
    - my-network

主机Mosquitto日志 #

1690385767: mosquitto version 2.0.15 starting 
1690385767: Config loaded from C:\Program Files\mosquitto/mosquitto.conf. 
1690385767: Opening ipv6 listen socket on port 1883. 
1690385767: Opening ipv4 listen socket on port 1883. 
1690385767: mosquitto version 2.0.15 running

mosquitto.conf配置 #

listener 1883
log_dest file C:\Users\andrea.palermo\Desktop\mosquitto.log
log_type all

错误日志 #

应用启动时错误 #

mqtt_1        | org.eclipse.paho.client.mqttv3.MqttException: Unable to connect to server
mqtt_1        |         at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:80) ~[org.eclipse.paho.client.mqttv3-1.2.5.jar!/:na]
mqtt_1        |         at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:724) ~[org.eclipse.paho.client.mqttv3-1.2.5.jar!/:na]
mqtt_1        |         at java.base/java.lang.Thread.run(Thread.java:829) ~[na:na]
mqtt_1        | Caused by: java.net.ConnectException: Connection refused (Connection refused)
mqtt_1        |         at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]
mqtt_1        |         at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:412) ~[na:na]
mqtt_1        |         at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:255) ~[na:na]
mqtt_1        |         at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:237) ~[na:na]
mqtt_1        |         at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:na]
mqtt_1        |         at java.base/java.net.Socket.connect(Socket.java:609) ~[na:na]
mqtt_1        |         at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:74) ~[org.eclipse.paho.client.mqttv3-1.2.5.jar!/:na]
mqtt_1        |         ... 2 common frames omitted

发布消息时错误 #

mqtt_1        | org.springframework.messaging.MessageHandlingException: error occurred in message handler [bean 'mqttOutbound'; defined in: 'class path resource [it/mqtt/mqttmanagement/beans/MqttBeans.class]'; from source: 'it.mqtt.mqttmanagement.beans.MqttBeans.mqttOutbound()']; nested exception is org.springframework.messaging.MessagingException: Failed to connect; nested exception is Unable to connect to server (32103) - java.net.ConnectException: Connection refused (Connection refused), failedMessage=GenericMessage [payload={"id_boat":"AAA","latitude":37,"longitude":15}, headers={replyChannel=nullChannel, id=aef51eec-4161-edd5-3c78-9c9df956ca9d, mqtt_topic=info/test, timestamp=1690443018860}]
mqtt_1        |         at org.springframework.integration.support.utils.IntegrationUtils.wrapInHandlingExceptionIfNecessary(IntegrationUtils.java:191)
mqtt_1        |         at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:64)
mqtt_1        |         at org.springframework.integration.handler.ReplyProducingMessageHandlerWrapper.handleRequestMessage(ReplyProducingMessageHandlerWrapper.java:59)
mqtt_1        |         at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:136)
mqtt_1        |         at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:55)
mqtt_1        |         at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
mqtt_1        |         at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
mqtt_1        |         at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
mqtt_1        |         at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:72)
mqtt_1        |         at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:317)
mqtt_1        |         at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:272)
mqtt_1        |         at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
mqtt_1        |         at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
mqtt_1        |         at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
mqtt_1        |         at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
mqtt_1        |         at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:151)
mqtt_1        |         at org.springframework.messaging.core.AbstractMessageSendingTemplate.convertAndSend(AbstractMessageSendingTemplate.java:143)
mqtt_1        |         at org.springframework.integration.gateway.MessagingGatewaySupport.send(MessagingGatewaySupport.java:428)
mqtt_1        |         at org.springframework.integration.gateway.GatewayProxyFactoryBean.sendOrSendAndReceive(GatewayProxyFactoryBean.java:657)
mqtt_1        |         at org.springframework.integration.gateway.GatewayProxyFactoryBean.invokeGatewayMethod(GatewayProxyFactoryBean.java:589)
mqtt_1        |         at org.springframework.integration.gateway.GatewayProxyFactoryBean.doInvoke(GatewayProxyFactoryBean.java:556)
mqtt_1        |         at org.springframework.integration.gateway.GatewayProxyFactoryBean.invoke(GatewayProxyFactoryBean.java:545)
mqtt_1        |         at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
mqtt_1        |         at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:220)
mqtt_1        |         at com.sun.proxy.$Proxy121.senToMqtt(Unknown Source)
mqtt_1        |         at it.mqtt.mqttmanagement.controller.MqttController.publishOtherBoats(MqttController.java:59)
mqtt_1        |         at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
mqtt_1        |         at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
mqtt_1        |         at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
mqtt_1        |         at java.base/java.lang.reflect.Method.invoke(Method.java:566)
mqtt_1        |         at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84)
mqtt_1        |         at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
mqtt_1        |         at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
mqtt_1        |         at java.base/java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305)
mqtt_1        |         at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305)
mqtt_1        |         at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
mqtt_1        |         at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
mqtt_1        |         at java.base/java.lang.Thread.run(Thread.java:829)
mqtt_1        | Caused by: org.springframework.messaging.MessagingException: Failed to connect; nested exception is Unable to connect to server (32103) - java.net.ConnectException: Connection refused (Connection refused)
mqtt_1        |         at org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler.checkConnection(MqttPahoMessageHandler.java:227)
mqtt_1        |         at org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler.publish(MqttPahoMessageHandler.java:237)
mqtt_1        |         at org.springframework.integration.mqtt.outbound.AbstractMqttMessageHandler.handleMessageInternal(AbstractMqttMessageHandler.java:269)
mqtt_1        |         at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:55)
mqtt_1        |         ... 36 more
mqtt_1        | Caused by: Unable to connect to server (32103) - java.net.ConnectException: Connection refused (Connection refused)
mqtt_1        |         at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:80)
mqtt_1        |         at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:724)
mqtt_1        |         ... 1 more
mqtt_1        | Caused by: java.net.ConnectException: Connection refused (Connection refused)
mqtt_1        |         at java.base/java.net.PlainSocketImpl.socketConnect(Native Method)
mqtt_1        |         at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:412)
mqtt_1        |         at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:255)
mqtt_1        |         at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:237)
mqtt_1        |         at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
mqtt_1        |         at java.base/java.net.Socket.connect(Socket.java:609)
mqtt_1        |         at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:74)
mqtt_1        |         ... 2 more

解决方案 #

1. 修改Mosquitto监听配置，允许外部连接 #

当前mosquitto.conf的listener 1883仅监听本地回环地址（127.0.0.1），Docker容器通过host.docker.internal访问时会被拒绝。需明确指定监听所有网卡：

listener 1883 0.0.0.0
log_dest file C:\Users\andrea.palermo\Desktop\mosquitto.log
log_type all

0.0.0.0表示监听所有可用网卡，确保Docker容器能通过host.docker.internal连接到Mosquitto。

2. 配置Windows防火墙规则 #

确保Windows防火墙允许Mosquitto服务的1883端口接收外部连接：

• 打开Windows Defender防火墙高级设置
• 添加入站规则，允许TCP端口1883的连接，或直接允许mosquitto.exe的网络访问权限

3. 替换连接地址为局域网IP（可选） #

若host.docker.internal存在解析问题，可直接使用主机的局域网IP（如192.168.x.x）替换：

mqttUrl: tcp://192.168.1.100:1883

4. 重启Mosquitto服务 #

修改配置后，在Windows服务管理器中找到“Mosquitto Broker”服务，右键重启以生效。

内容的提问来源于stack exchange，提问作者Andrea Palermo