<!-- MQTT -->
        <dependency>
            <groupId>org.eclipse.paho</groupId>
            <artifactId>org.eclipse.paho.client.mqttv3</artifactId>
            <version>1.2.5</version>
        </dependency>

server:
  port: 8081

#允許循環(huán)依賴
spring:
  main:
    allow-circular-references: true

customer:
  mqtt:
    broker: tcp://localhost:1883
    clientList:
      #發(fā)布客戶端ID
      - clientId: nays_service
        #監(jiān)聽(tīng)主題 同時(shí)訂閱多個(gè)主題 使用 - 分割開(kāi)
        subscribeTopic: mqtt/publish
        #用戶名
        userName: admin
        #密碼
        password: public
      #接收客戶端ID
      - clientId: receive_service
        #監(jiān)聽(tīng)主題 同時(shí)訂閱多個(gè)主題 使用 - 分割開(kāi)
        subscribeTopic: mqtt/receive
        #用戶名
        userName: admin
        #密碼
        password: public

package com.hulei.mqttproject.config;

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;

import java.util.List;

/**
 * Mqtt配置類
 */
@Data
@Configuration
@ConfigurationProperties(prefix = "customer.mqtt")
public class MqttConfig {
    /**
     * mqtt broker地址
     */
    String broker;
    /**
     * 需要?jiǎng)?chuàng)建的MQTT客戶端
     */
    List<MqttClient> clientList;
}

package com.hulei.mqttproject.config;

import lombok.Data;


/**
 * MQTT客戶端
 */
@Data
public class MqttClient {
    /**
     * 客戶端ID
     */
    private String clientId;
    /**
     * 監(jiān)聽(tīng)主題
     */
    private String subscribeTopic;
    /**
     * 用戶名
     */
    private String userName;
    /**
     * 密碼
     */
    private String password;
}

package com.hulei.mqttproject.config;

import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * MQTT客戶端管理類,如果客戶端非常多后續(xù)可入redis緩存
 */
@Slf4j
@Component
public class MqttClientManager {

    @Value("${customer.mqtt.broker}")
    private String mqttBroker;

    @Resource
    private MqttCallBackContext mqttCallBackContext;
    /**
     * 存儲(chǔ)MQTT客戶端
     */
    public static Map<String, MqttClient> MQTT_CLIENT_MAP = new ConcurrentHashMap<>();

    public MqttClient getMqttClientById(String clientId) {
        return MQTT_CLIENT_MAP.get(clientId);
    }

    /**
     * 創(chuàng)建mqtt客戶端
     *
     * @param clientId       客戶端ID
     * @param subscribeTopic 訂閱主題，可為空
     * @param userName       用戶名，可為空
     * @param password       密碼，可為空
     */
    public void createMqttClient(String clientId, String subscribeTopic, String userName, String password) {
        MemoryPersistence persistence = new MemoryPersistence();
        try {
            MqttClient client = new MqttClient(mqttBroker, clientId, persistence);
            MqttConnectOptions connOpts = new MqttConnectOptions();
            if (null != userName && !userName.isEmpty()) {
                connOpts.setUserName(userName);
            }

            if (null != password && !password.isEmpty()) {
                connOpts.setPassword(password.toCharArray());
            }

            connOpts.setCleanSession(true);

            if (null != subscribeTopic && !subscribeTopic.isEmpty()) {
                AbsMqttCallBack callBack = mqttCallBackContext.getCallBack(clientId);

                if (null == callBack) {
                    callBack = mqttCallBackContext.getCallBack("default");
                }

                callBack.setClientId(clientId);
                callBack.setConnectOptions(connOpts);
                client.setCallback(callBack);
            }

            //連接mqtt服務(wù)端broker
            client.connect(connOpts);
            // 訂閱主題
            if (null != subscribeTopic && !subscribeTopic.isEmpty()) {
                if (subscribeTopic.contains("-"))
                    client.subscribe(subscribeTopic.split("-"));
                else {
                    client.subscribe(subscribeTopic);
                }
            }

            MQTT_CLIENT_MAP.putIfAbsent(clientId, client);
        } catch (MqttException e) {
            log.error("Create mqttClient failed!", e);
        }
    }
}

package com.hulei.mqttproject.config;

import jakarta.annotation.PostConstruct;
import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import java.util.List;

/**
 * MQTT客戶端創(chuàng)建
 */
@Component
@Slf4j
public class MqttClientCreate {
    @Resource
    private MqttClientManager mqttClientManager;
    @Resource
    private MqttConfig mqttConfig;

    /**
     * 創(chuàng)建MQTT客戶端
     */
    @PostConstruct
    public void createMqttClient() {
        List<MqttClient> mqttClientList = mqttConfig.getClientList();

        for (MqttClient mqttClient : mqttClientList) {
            log.info("{}", mqttClient);
            //創(chuàng)建客戶端，客戶端ID：demo，回調(diào)類跟客戶端ID一致
            mqttClientManager.createMqttClient(mqttClient.getClientId(), mqttClient.getSubscribeTopic(), mqttClient.getUserName(), mqttClient.getPassword());
        }
    }
}

package com.hulei.mqttproject.config;

import jakarta.annotation.Resource;
import lombok.Getter;
import lombok.Setter;
import lombok.extern.slf4j.Slf4j;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttMessage;

/**
 * MQTT回調(diào)抽象類
 */
@Setter
@Getter
@Slf4j
public abstract class AbsMqttCallBack implements MqttCallback {

    private String clientId;

    private MqttConnectOptions connectOptions;

    @Resource
    MqttClientManager mqttClientManager;

    /**
     * 失去連接操作,進(jìn)行重連
     *
     * @param throwable 異常
     */
    @Override
    public void connectionLost(Throwable throwable) {
        try {
            if (null != clientId) {
                if (null != connectOptions) {
                    mqttClientManager.getMqttClientById(clientId).connect(connectOptions);
                } else {
                    mqttClientManager.getMqttClientById(clientId).connect();
                }
            }

        } catch (Exception e) {
            log.error("{} reconnect failed!", e.getMessage(), e);
        }
    }

    /**
     * 接收訂閱消息
     * @param topic    主題
     * @param mqttMessage 接收消息
     * @throws Exception 異常
     */
    @Override
    public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
		String content = new String(mqttMessage.getPayload());
     	handleReceiveMessage(topic, content);
    }

    /**
     * 消息發(fā)送成功
     *
     * @param iMqttDeliveryToken toke
     */
    @Override
    public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
        log.info("消息發(fā)送成功");
    }


    /**
     * 處理接收的消息
     * @param topic   主題
     * @param message 消息內(nèi)容
     */
    protected abstract void handleReceiveMessage(String topic, String message);
}

package com.hulei.mqttproject.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * MQTT訂閱回調(diào)環(huán)境類
 */
@Component
@Slf4j
public class MqttCallBackContext {

    private final Map<String, AbsMqttCallBack> callBackMap = new ConcurrentHashMap<>();

    /**
     * 默認(rèn)構(gòu)造函數(shù)
     *
     * @param callBackMap 回調(diào)集合
     */
    public MqttCallBackContext(Map<String, AbsMqttCallBack> callBackMap) {
        this.callBackMap.putAll(callBackMap);
    }

    /**
     * 獲取MQTT回調(diào)類
     *
     * @param clientId 客戶端ID
     * @return MQTT回調(diào)類
     */
    public AbsMqttCallBack getCallBack(String clientId) {
        return this.callBackMap.get(clientId);
    }
}

package com.hulei.mqttproject.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

/**
 * 默認(rèn)回調(diào)
 */
@Slf4j
@Component("default")
public class DefaultMqttCallBack extends AbsMqttCallBack {

    /**
     * @param topic   主題
     * @param message 消息內(nèi)容
     */
    @Override
    protected void handleReceiveMessage(String topic, String message) {
        log.info("接收到主題---{}", topic);
        log.info("接收到消息---{}", message);
        // 自定義消息處理業(yè)務(wù)

    }
}

package com.hulei.mqttproject.controller;

import com.hulei.mqttproject.config.MqttClientManager;
import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@Slf4j
public class SendController {

    @Resource
    private MqttClientManager mqttClientManager;

    @RequestMapping("/sendMessage")
    public String sendMessage(String topic){
        try {
            MqttMessage mqttMessage = new MqttMessage("你好".getBytes());
            mqttClientManager.getMqttClientById("nays_service").publish(topic,mqttMessage);
            return "發(fā)送成功";
        } catch (Exception e) {
            log.error("發(fā)送失敗",e);
            return "發(fā)送失敗";
        }
    }
}