I have a Spring Boot application that I’m using with Mqtt Paho. I’ve created an Mqtt Configuration class to connect to the broker and subscribe to a test topic. I also have an MqttListener class to handle messages. The Listener bean is being initialized but my Mqtt methods are not being called. I have determined it it most liekly because my MqttClient is not being injected into this class, but I could be wrong.

Here is my MqttClient:

package com.example.javaproject.listener;

@Configuration
public class MqttConfig {

    @Bean
    public MqttClient mqttClient() throws MqttException {
        MqttClient client = new MqttClient(broker, clientId);
        MqttConnectOptions options = new MqttConnectOptions();
        options.setUserName("skaxi");
        options.setPassword("M@ji2222".toCharArray());
        client.connect(options);
        if (client.isConnected()) {
            System.out.println("client connected");
            client.subscribe("test-topic");
            System.out.println("subscribed to topics");
        }
        return client;

    }

}

Here is my Listener:

package com.example.javaproject.config;

@Service
public class MqttMessageListener  implements  MqttCallbackExtended{

    @Autowired
    MessageRepository messageRepository;

    @Autowired
    private MqttClient mqttClient;

    public MqttMessageListener(){

    }

    @PostConstruct
    public void init() {
        System.out.println("MqttMessageListener initialized successfully");

    }


    @Override
    public void connectComplete(boolean b, String s) {
        System.out.println("connected message from listener");
    }

    @Override
    public void connectionLost(Throwable throwable) {
        System.out.println("connection lost");
    }

    @Override
    public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
        String content = mqttMessage.toString();
        Message message = new Message(topic, content);
        System.out.println("message arrived triggered: " + content);

        try{
            messageRepository.save(message);
            System.out.println("message saved to database");
        }catch(Exception e){
            System.out.println("error saving to database: " + e.getMessage());
        }
    }

    @Override
    public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
        System.out.println("delivery complete");
    }
}

Any ideas would be appreciated. Thank you

I have tried injecting the client through the Listeners constructor as well as field injection but I still get nothing. I have seen in the logs that the mqttClient bean is being created so maybe that’s not the problem.