Ubidots MQTT with Java

UbidotsMQTTJava.java

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package mqttexample;

import java.io.UnsupportedEncodingException;
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.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.MqttPersistenceException;
import org.eclipse.paho.client.mqttv3.persist.MqttDefaultFilePersistence;

/**
 *
 * @author jota
 */
public class MqttExample {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws MqttException, UnsupportedEncodingException {
        // MQTT Broker Setup        
        String brokerUrl     = "tcp://industrial.api.ubidots.com:1883";
	String topic         = "/v1.6/devices/my-device";
        String token         = "";  // Fill here with your token
        
        // Data setup
        String deviceLabel   = "my-device";
        String variableLabel = "my-var";
        String testValue     = "11";
        String payload       = "{\"" + variableLabel + "\": " + testValue + "}";
        int qos=0;

        String tmpDir = System.getProperty("java.io.tmpdir");
        MqttDefaultFilePersistence dataStore = new MqttDefaultFilePersistence(tmpDir);
        
        // Creates the MQTT client
        MqttClient client;
	MqttConnectOptions conOpt;
        
        conOpt = new MqttConnectOptions();
        conOpt.setCleanSession(true);
        conOpt.setUserName(token);
        
        client = new MqttClient(brokerUrl,MqttClient.generateClientId(), dataStore);
        
        if(!client.isConnected()){
            System.out.println("Connecting to broker ...");
	    client.connect(conOpt);
        }
        
        // Sends Data
        MqttMessage message = new MqttMessage(payload.getBytes("UTF-8"));
        message.setQos(qos);
        
        client.publish(topic, message);
        client.disconnect();
    }
    
}