Simple MQTT Client in Java

A simple asynchronous MQTT client written in Java.

Download

You can either download the zip file from the releases on Github here or use Maven. If you are using Maven, add the following to your project pom.xml file.

<project ...>
...
<repositories>
    <repository>
        <id>LTG</id>
        <url>http://ltg.evl.uic.edu/artifactory/repo</url>
    </repository>
</repositories>
...
<dependencies>
    <dependency>
        <groupId>ltg</groupId>
        <artifactId>simple-java-mqtt-client</artifactId>
        <version>1.0.3</version>
    </dependency>
</dependencies>
...
</project>

Hello world

import ltg.commons.SimpleMQTTClient;

public class MQTTClientDemo {

	public static void main(String[] args) {
        // Create a new client and connect to a broker
		SimpleMQTTClient sc = new SimpleMQTTClient("localhost");

        // Subscribe to a channel and register a callback for it
        sc.subscribe("myChannel", new MessageListener() {
            @Override
            public void processMessage(String message) {
                System.out.println(message);
            }
        });
    
        // Publish to a channel
        sc.publish("myOtherChannel", "A message from me");
    
        // Unsubscribe from a channel
        sc.unsubscribe("myChannel");

		// Disconnect from broker
		sc.disconnect();

		// Do something else or the client will die...
        // while (!Thread.currentThread().isInterrupted()) {
        // }
	}
}

For a complete example see MQTTClientDemo.java in ltg.commons.examples.

Important note

This library is based off of the fusesource mqtt library .