使用paho.client.mqttv3连接mqtt并发送消息,为什么生成了多个.lck文件?
时间: 2024-05-17 16:05:47
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Paho[客户端使用](https://wenku.csdn.net/doc/jjzwnwxamh?spm=1055.2569.3001.10083)`.lck`文件来锁定存储,以确保在同一时间只有一个进程可以访问存储。当您使用`paho.[c[lient](https://wenku.csdn.net/doc/4w37qxh88q?spm=1055.2569.3001.10083)](https://wenku.csdn.net/doc/6412b721be7fbd1778d4933e?spm=1055.2569.3001.10083).[mqttv3](https://wenku.csdn.net/doc/rq27uuoy66?spm=1055.2569.3001.10083)`连接MQTT并发送消息时,Paho客户端会在本地存储中创建`.lck`文件。如果您在连接多个MQTT代理或使用多个Paho客户端实例,则可能会看到多个`.lck`文件。
这些`.lck`文件应该是自动删除的,但是如果在程序异常退出或意外终止时未正确释放锁,则可能会导致`.lck`文件残留。如果您的系统中存在多个`.lck`文件,请确保您的程序正确处理锁定并释放它们,或者手动删除这些文件。
相关问题
Cannot invoke "org.eclipse.paho.client.mqttv3.MqttClient.getTopic(String)" because "this.mqttClient" is null
这个错误的原因是你在调用 MqttClient 的 getTopic 方法之前,没有对 mqttClient 进行初始化。你需要在调用该方法之前,先对 mqttClient 进行初始化,例如:
MqttClient mqttClient = new MqttClient(brokerUrl, clientId);
mqttClient.connect();
MqttTopic topic = mqttClient.getTopic(topicName);
其中,brokerUrl 是 MQTT 服务器的地址,clientId 是你的客户端ID,topicName 是你要订阅或发布的主题名称。在初始化完成后,你就可以调用 getTopic 方法来获取对应的主题对象了。
A component required a bean of type 'org.eclipse.paho.client.mqttv3.MqttClient' that could not be found.
根据提供的引用内容,你遇到的问题是组件需要一个类型为'org.eclipse.paho.client.mqttv3.MqttClient'的bean,但找不到该bean。这可能是
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