我正在使用Java Spring应用程序中的HiveMQ库连接到Mosquito实例，因为与Paho客户端相比，它更用户友好。但自动重新连接出现了问题。连接不时丢失，应用程序无法成功重新连接(请参阅日志1(。这也可以通过重新启动Mosquitto代理程序本身来触发(请参阅日志2(。
这是我的客户端构建程序代码，在断开连接时添加了额外的日志记录，以检查凭据是否仍然正确：
client = MqttClient.builder()
.useMqttVersion5()
.identifier(identifier)
.serverHost(host)
.serverPort(port)
.sslWithDefaultConfig()
// https://www.hivemq.com/blog/hivemq-mqtt-client-features/reconnect-handling/
.automaticReconnectWithDefaultConfig()
.addDisconnectedListener(context -> logger.error("MQTT user {} with identifier {} on {}:{} has disconnected reason: {}",
username, identifier, host, port, context.getCause().getMessage()))
.buildAsync();
client.connectWith()
.simpleAuth()
.username(username)
.password(password.getBytes())
.applySimpleAuth()
.cleanStart(false)
.keepAlive(60)
.send();
1/在应用程序本身丢失连接后，我的日志中会显示这一点：
2022-03-16 02:10:33.502 ERROR 1 --- [client.mqtt-1-2] MqttConfig : MQTT user *** with identifier SERVICE on ***:8883 has disconnected reason: Timeout while waiting for PINGRESP
2022-03-16 02:11:25.090 ERROR 1 --- [client.mqtt-1-2] MqttConfig : MQTT user *** with identifier SERVICE on ***:8883 has disconnected reason: CONNECT failed as CONNACK contained an Error Code: NOT_AUTHORIZED.
2022-03-16 02:12:27.200 ERROR 1 --- [client.mqtt-1-2] MqttConfig : MQTT user *** with identifier SERVICE on ***:8883 has disconnected reason: Timeout while waiting for CONNACK
2/这是代理重新启动后的日志，一些预期的超时，但最后也是"超时"；未授权"：
2022-03-16 10:17:37.178 ERROR 1 --- [client.mqtt-1-2] MqttConfig : MQTT user *** with identifier SERVICE on ***:8883 has disconnected reason: Server closed connection without DISCONNECT.
2022-03-16 10:17:48.441 ERROR 1 --- [client.mqtt-1-2] MqttConfig : MQTT user *** with identifier SERVICE on ***:8883 has disconnected reason: io.netty.channel.ConnectTimeoutException: connection timed out: ***/***:8883
2022-03-16 10:18:00.747 ERROR 1 --- [client.mqtt-1-2] MqttConfig : MQTT user *** with identifier SERVICE on ***:8883 has disconnected reason: io.netty.channel.ConnectTimeoutException: connection timed out: ***/***:8883
2022-03-16 10:18:10.625 ERROR 1 --- [client.mqtt-1-2] MqttConfig : MQTT user *** with identifier SERVICE on ***:8883 has disconnected reason: io.netty.channel.AbstractChannel$AnnotatedConnectException: finishConnect(..) failed: No route to host: ***/***:8883
2022-03-16 10:18:26.845 ERROR 1 --- [client.mqtt-1-2] MqttConfig : MQTT user *** with identifier SERVICE on ***:8883 has disconnected reason: io.netty.channel.ConnectTimeoutException: connection timed out: ***/***:8883
2022-03-16 10:18:42.584 ERROR 1 --- [client.mqtt-1-2] MqttConfig : MQTT user *** with identifier SERVICE on ***:8883 has disconnected reason: CONNECT failed as CONNACK contained an Error Code: NOT_AUTHORIZED.
在这两种情况下，连接都会随着应用程序的重新启动而恢复正常。
有什么想法吗？
您的问题似乎在本期中得到了回答：
如果在连接调用中设置用户名和密码，则在客户端重新连接时(出于安全原因(，这些用户名和密码将不会被存储和重用。
以下代码(来自上面链接的问题(演示了该方法：
Mqtt3Client.builder()
.identifier("ePCR mobile-" + currentTimeMillis())
.serverHost(config.getHost())
.serverPort(config.getPort())
.automaticReconnectWithDefaultConfig()
.simpleAuth()
.username(config.getUsername())
.password(config.getPassword())
.applySimpleAuth()
.buildRx();