如何在数据库中存储MQTT订阅的数据

Question

I am using MQTT Paho MqttCallback I am successfully able to subscribe and publish on my topic without any issues but, my task is to store the data in database which is getting in messageArrived(String topic, MqttMessage message) so the data I can use it in future.

@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
    // code to store the message in database
     LOGGER.info("messageArrived>> " + message);
}

messageArrived() is not executing the code which is storing to database its simply executing the LOGGER that's. Code to store the message in database is correct then also it is skipping the code. What strategy do I need to apply so first it will store the message in database and prints the log.

update

I am trying something similar to this

Answer 1

This will be because your logger/database code it throwing an exception that is getting swallowed by the paho framework.

Add a try/catch block round your Logger call.

@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
     try {
         // code to store the message in database
         LOGGER.info("messageArrived>> " + message);
     } catch (Exception ex) {
         System.err.println(ex);
     }
}

Now it should print the reason for the failure to stderr