Sample MQTT Publish Program in Java

MyMqttApp.java

package org.mqtt.app;

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

/**
 * @author anadi
 *
 */
public class MyMqttApp implements MqttCallback {

  private MqttClient myClient;
  private MqttConnectOptions connectOptions;

  private static final String BROKER_URL = "tcp://m2m.eclipse.org:1883";

  private static final String MY_MQTT_CLIENT_ID = "tony-stark";
  
  private static final String DEFAULT_TOPIC = "/alchemy/room9/test";

  private static final boolean PUBLISHER = true;
  private static final boolean SUBSCRIBER = false;

  private static final int RETRIES = 3;

  /**
   * @param args
   */
  public static void main(String[] args) throws Exception {

    MyMqttApp app = new MyMqttApp();
    app.runClient();
    app.sendMessage(DEFAULT_TOPIC, "Hello From My MQTT APP");
    Thread.sleep(200);
    app.stopClient();

  }

  /**
   * @throws MqttException
   */
  public MyMqttApp() throws MqttException {
    myClient = new MqttClient(BROKER_URL, MY_MQTT_CLIENT_ID);
    myClient.setCallback(this);
  }

  public void runClient() {

    connectOptions = new MqttConnectOptions();
    connectOptions.setCleanSession(true);
    connectOptions.setKeepAliveInterval(100);

    try {

      System.out.println("Attempting Connection to " + BROKER_URL);
      myClient.connect(connectOptions);
      System.out.println("Connected to " + BROKER_URL);
      

    } catch (MqttException me) {

      System.err.println(me.getMessage());
      System.err.println(me.getStackTrace());
      System.exit(-1);
    }

  }

  @Override
  public void connectionLost(Throwable arg0) {
    // TODO Auto-generated method stub
    System.out.println("Connection lost!");
  }

  @Override
  public void deliveryComplete(IMqttDeliveryToken arg0) {
    System.out.println("Devliery completed with token ::");
    System.out.println("Message Id :: " + arg0.getMessageId());
    System.out.println("Response :: " + arg0.getResponse().toString());

  }

  @Override
  public void messageArrived(String arg0, MqttMessage arg1) throws Exception {
    System.out.println("Recieved Message :: -----------------------------");
    System.out.println("| Topic:" + arg0);
    System.out.println("| Message: " + new String(arg1.getPayload()));
    System.out.println("End ---------------------------------------------");
  }

  public void sendMessage(String topic, String message) throws InterruptedException {

    System.out.println("Building message with " + message.getBytes().length + "bytes of payload");
    MqttMessage mqttMessage = new MqttMessage(message.getBytes());
    mqttMessage.setQos(0);
    mqttMessage.setRetained(false);

    MqttTopic mqttTopic = myClient.getTopic(topic);

    MqttDeliveryToken token = null;

    try {
      token = mqttTopic.publish(mqttMessage);
      Thread.sleep(100);
      token.waitForCompletion();
    } catch (MqttException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }

    if (null != token) {
      System.out.println("Published with Token ::");
      System.out.println(token.getMessageId());
    }
  }
  
  public void stopClient() throws MqttException {
    myClient.disconnect();
    System.out.println("Disonnected from " + BROKER_URL);
    System.exit(0);
  }
}