【MQTT】

<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-mqtt</artifactId>
    <version>6.2.2</version> <!-- 或与你 Spring 兼容的版本 -->
</dependency>

<dependency>
    <groupId>org.eclipse.paho</groupId>
    <artifactId>org.eclipse.paho.client.mqttv3</artifactId>
    <version>1.2.5</version> <!-- 注意：存在已知漏洞，需内部审查通过 -->
</dependency>

package com.example.mqtt;

import org.eclipse.paho.client.mqttv3.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class MqttStaticSender {

    private static final Logger logger = LoggerFactory.getLogger(MqttStaticSender.class);

    private static final String BROKER_URL = "tcp://broker.hivemq.com:1883";
    private static final String CLIENT_ID = "static-java-client";
    private static final String DEFAULT_TOPIC = "default/topic";
    private static final int QOS = 1;

    private static MqttClient mqttClient;

    static {
        try {
            mqttClient = new MqttClient(BROKER_URL, CLIENT_ID, null);
            MqttConnectOptions options = new MqttConnectOptions();
            options.setCleanSession(true);
            mqttClient.connect(options);
            logger.info("【MQTT】连接成功 -> broker: {}", BROKER_URL);
        } catch (Exception e) {
            logger.error("【MQTT】初始化失败", e);
        }
    }

    public static void send(String topic, String message) {
        try {
            if (!mqttClient.isConnected()) {
                mqttClient.reconnect();
                logger.warn("【MQTT】连接已断开，已重新连接");
            }

            MqttMessage mqttMessage = new MqttMessage(message.getBytes());
            mqttMessage.setQos(QOS);

            mqttClient.publish(topic, mqttMessage);
            logger.info("【MQTT】发送成功 -> topic: {}, payload: {}", topic, message);
        } catch (Exception e) {
            logger.error("【MQTT】发送失败 -> topic: {}, payload: {}", topic, message, e);
        }
    }

    public static void send(String message) {
        send(DEFAULT_TOPIC, message);
    }

    public static void close() {
        try {
            if (mqttClient != null && mqttClient.isConnected()) {
                mqttClient.disconnect();
                mqttClient.close();
                logger.info("【MQTT】连接已关闭");
            }
        } catch (Exception e) {
            logger.error("【MQTT】关闭连接失败", e);
        }
    }
}