SpringBoot集成MQTT实现交互服务通信

import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.MqttCallback;
 
public class MqttService {
 
    private MqttClient mqttClient;
    private MqttConnectOptions mqttConnectOptions;
 
    public void start() {
        try {
            mqttClient = new MqttClient("tcp://broker.hivemq.com:1883", MqttClient.generateClientId());
            mqttConnectOptions = new MqttConnectOptions();
            mqttConnectOptions.setUserName("username");
            mqttConnectOptions.setPassword("password".toCharArray());
            mqttConnectOptions.setCleanSession(true);
 
            mqttClient.connect(mqttConnectOptions);
            mqttClient.setCallback(new MqttCallback() {
                @Override
                public void connectionLost(Throwable cause) {
                    // 连接丢失后的回调
                }
 
                @Override
                public void messageArrived(String topic, MqttMessage message) throws Exception {
                    // 接收到消息的回调
                }
 
                @Override
                public void deliveryComplete(IMqttDeliveryToken token) {
                    // 消息发送成功的回调
                }
            });
 
            mqttClient.subscribe("topic");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    public void publish(String topic, String payload) {
        try {
            MqttMessage message = new MqttMessage(payload.getBytes());
            mqttClient.publish(topic, message);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    public void stop() {
        try {
            mqttClient.disconnect();
            mqttClient.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

这个简单的例子展示了如何在SpringBoot应用中集成MQTT客户端，并实现消息的发布和订阅。代码中包含了连接MQTT服务器（例如HiveMQ的公共服务器），订阅特定主题，接收消息，以及发布消息到特定主题的基本操作。在实际应用中，你需要根据自己的需求和服务器配置相应地调整连接选项和服务器地址。