Simple MQTT subscribe example using the Eclipse Paho Java Client

gistfile1.txt

import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;

public class HelloMQTT implements MqttCallback {
	MqttClient client;
	private MqttConnectOptions conOpt;
	
  private static final String SERVER_URI = "tcp://broker.hivemq.com:1883";
	private static final String MQTT_CLIENT_PASSWORD = "TBD";
	private static final String MQTT_CLIENT_USERNAME = "TBD";

	

	public HelloMQTT() {
	}

	public static void main(String[] args) {

		new HelloMQTT().init();
	}


	public void init() {
		
		System.out.println("HelloMQTT Demo");
		String id = client.generateClientId();
			
		try {
			client = new MqttClient(SERVER_URI, id);

			conOpt = new MqttConnectOptions();
	    	conOpt.setCleanSession(true);
	    	conOpt.setKeepAliveInterval(15);
	    	
	    	conOpt = new MqttConnectOptions();
	    	conOpt.setUserName(MQTT_CLIENT_USERNAME);
	    	conOpt.setPassword(MQTT_CLIENT_PASSWORD.toCharArray());
			

			client.connect(conOpt);
			client.setCallback(this);
			client.subscribe("#"); 	// Wildcard all topics
		
		} catch (MqttException e) {
			e.printStackTrace();
		}
	}

	@Override
	public void connectionLost(Throwable cause) {
		// TODO Auto-generated method stub

	}

	@Override
	public void messageArrived(String topic, MqttMessage message) throws Exception {
		System.out.println(topic +" " + message);
	}

	@Override
	public void deliveryComplete(IMqttDeliveryToken token) {
		// TODO Auto-generated method stub

	}

}