【MQTT】使用MQTT在Spring Boot项目中实现异步消息通信

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.persist.MemoryPersistence;
 
public class MqttPublisher {
 
    private MqttClient mqttClient;
    private final String brokerUrl = "tcp://localhost:1883";
    private final String clientId = "JavaClient";
    private final MemoryPersistence memoryPersistence = new MemoryPersistence();
 
    public void connect() throws MqttException {
        MqttConnectOptions connOpts = new MqttConnectOptions();
        connOpts.setCleanSession(true);
        mqttClient = new MqttClient(brokerUrl, clientId, memoryPersistence);
        mqttClient.connect(connOpts);
    }
 
    public void publish(String topic, String payload) throws MqttException {
        MqttMessage message = new MqttMessage(payload.getBytes());
        mqttClient.publish(topic, message);
    }
 
    public void disconnect() throws MqttException {
        if (mqttClient.isConnected()) {
            mqttClient.disconnect();
        }
    }
 
    public static void main(String[] args) {
        MqttPublisher publisher = new MqttPublisher();
        try {
            publisher.connect();
            publisher.publish("mqtt/example", "Hello MQTT");
            publisher.disconnect();
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }
}

这段代码展示了如何在Java中使用Eclipse Paho客户端库连接到MQTT代理，发布消息到特定的主题，并在完成消息发送后断开连接。这是一个简化的例子，用于演示如何在Spring Boot项目中实现MQTT消息的发送。