生产环境 MQTT 连接异常排查报告
一、报错内容
在 Spring Integration 集成 MQTT 客户端进行消息发送时，系统抛出如下异常堆栈：
Caused by: org.springframework.messaging.MessagingException: Failed to connect at org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler.checkConnection(MqttPahoMessageHandler.java:224) at org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler.publish(MqttPahoMessageHandler.java:238) ... Caused by: org.eclipse.paho.client.mqttv3.MqttException: 无法连接至服务器 at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:80) at org.eclipse.paho.client.mqttv3.internal.SSLNetworkModule.start(SSLNetworkModule.java:132) ... Caused by: java.net.Con
