RabbitMQ用作MQTT服务器

第一步开启MQTT插件，开启Web MQTT插件，WebMQTT用来前端websocket连接mqtt。参考：https://blog.51cto.com/guzt/3995771

本人遇到的问题外部计算机无法连接mqtt，原因：没开webmqtt，然后防火墙还把请求给拦截了，导致其他计算机无法访问。遇到类似情况可以在RabbitMQ控制台查看是否开启webmqtt。之后可以让外部计算机用cmd的telnet ip 端口，来测试是否能访问服务器。

监听
package com.jqxx.digtwinresop.module.equipment.mqtt;

import io.netty.util.CharsetUtil;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttCallbackExtended;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.Resource;
import java.util.Map;

/*
    监听接受消息
 */

public class JwMqttCallback implements MqttCallbackExtended {
    //手动注入
    @Resource
    private MQTTConfig mqttConfig;

//    private MQTTConfig mqttConfig = SpringUtils.getBean(MQTTConfig.class);

    private static final Logger log = LoggerFactory.getLogger(JwMqttCallback.class);

    private JwMqttClient jwMqttClient;

    public JwMqttCallback(JwMqttClient jwMqttClient) {
        this.jwMqttClient = jwMqttClient;
    }

    /**
     * 丢失连接，可在这里做重连
     * 只会调用一次
     *
     * @param throwable
     */
    @Override
    public void connectionLost(Throwable throwable) {
        log.error("mqtt connectionLost 连接断开，5S之后尝试重连: {}", throwable.getMessage());
        long reconnectTimes = 1;
        while (true) {
            try {
                if (jwMqttClient.getClient().isConnected()) {
                    //判断已经重新连接成功  需要重新订阅主题 可以在这个if里面订阅主题  或者 connectComplete（方法里面）  看你们自己选择
                    log.warn("mqtt reconnect success end  重新连接  重新订阅成功");
                    return;
                }
                reconnectTimes+=1;
                log.warn("mqtt reconnect times = {} try again...  mqtt重新连接时间 {}", reconnectTimes, reconnectTimes);
                jwMqttClient.getClient().reconnect();
            } catch (MqttException e) {
                log.error("mqtt断连异常", e);
            }
            try {
                Thread.sleep(5000);
            } catch (InterruptedException e1) {
            }
        }
    }

    /**
     * @param topic
     * @param mqttMessage
     * @throws Exception
     * subscribe后得到的消息会执行到这里面
     */
    @Override
    public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
        log.info("MQTT接收消息主题 : {}，接收消息内容 : {}", topic, new String(mqttMessage.getPayload()));
        //发布消息主题
        if (topic.equals("gj/embed/resp")){
//            Map maps = (Map) JSON.parse(new String(mqttMessage.getPayload(), CharsetUtil.UTF_8));
            //你自己的业务接口
//            insertCmdResults(maps);
        }
        //接收报警主题
        if (topic.equals("gj/embed/warn")){
//            Map maps = (Map) JSON.parse(new String(mqttMessage.getPayload(), CharsetUtil.UTF_8));
            //你自己的业务接口
//            insertPushAlarm(maps);
        }
        if (topic.equals("dp")) {
            log.info("主题为dp");
        }
    }

    /**
     *连接成功后的回调 可以在这个方法执行 订阅主题  生成Bean的 MqttConfiguration方法中订阅主题 出现bug
     *重新连接后  主题也需要再次订阅  将重新订阅主题放在连接成功后的回调 比较合理
     * @param reconnect
     * @param serverURI
     */
    @Override
    public void connectComplete(boolean reconnect,String serverURI){
        log.info("MQTT 连接成功，连接方式：{}",reconnect?"重连":"直连");
        //订阅主题
//        jwMqttClient.subscribe(mqttConfiguration.topic1, 1);
//        jwMqttClient.subscribe(mqttConfiguration.topic2, 1);
//        jwMqttClient.subscribe(mqttConfiguration.topic3, 1);
//        jwMqttClient.subscribe(mqttConfiguration.topic4, 1);
    }

    /**
     * 消息到达后
     * subscribe后，执行的回调函数
     *
     * @param s
     * @param mqttMessage
     * @throws Exception
     */
    /**
     * publish后，配送完成后回调的方法
     *
     * @param iMqttDeliveryToken
     */
    @Override
    public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
        log.info("==========deliveryComplete={}==========", iMqttDeliveryToken.isComplete());
    }
}
发布订阅主题
package com.jqxx.digtwinresop.module.equipment.mqtt;

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

import java.nio.charset.Charset;

/**
 * 发送订阅消息
 */
public class JwMqttClient {
    private static final Logger LOGGER = LoggerFactory.getLogger(JwMqttClient.class);

    private static MqttClient client;
    private String host;
    private String username;
    private String password;
    private String clientId;
    private int timeout;
    private int keepalive;
    public JwMqttClient(String host, String username, String password, String clientId, int timeOut, int keepAlive) {
        this.host = host;
        this.username = username;
        this.password = password;
        this.clientId = clientId;
        this.timeout = timeOut;
        this.keepalive = keepAlive;
    }

    public static MqttClient getClient() {
        return client;
    }

    public static void setClient(MqttClient client) {
        JwMqttClient.client = client;
    }

    /**
     * 设置mqtt连接参数
     *
     * @param username
     * @param password
     * @param timeout
     * @param keepalive
     * @return
     */
    public MqttConnectOptions setMqttConnectOptions(String username, String password, int timeout, int keepalive) {
        MqttConnectOptions options = new MqttConnectOptions();
        options.setUserName(username);
        options.setPassword(password.toCharArray());
        options.setConnectionTimeout(timeout);
        options.setKeepAliveInterval(keepalive);
        options.setCleanSession(true);
        options.setAutomaticReconnect(true);
        return options;
    }

    /**
     * 连接mqtt服务端，得到MqttClient连接对象
     */
    public void connect() throws MqttException {
        if (client == null) {
            client = new MqttClient(host, clientId, new MemoryPersistence());
            client.setCallback(new JwMqttCallback(JwMqttClient.this));
        }
        MqttConnectOptions mqttConnectOptions = setMqttConnectOptions(username, password, timeout, keepalive);
        if (!client.isConnected()) {
            client.connect(mqttConnectOptions);
        } else {
            client.disconnect();
            client.connect(mqttConnectOptions);
        }
        LOGGER.info("MQTT connect success");//未发生异常，则连接成功
    }

    /**
     * 发布，默认qos为0，非持久化
     *
     * @param pushMessage
     * @param topic
     */
    public void publish(String pushMessage, String topic) {
        publish(pushMessage, topic, 0, false);
    }

    /**
     * 发布消息
     *
     * @param pushMessage
     * @param topic
     * @param qos
     * @param retained:留存
     */
    public void publish(String pushMessage, String topic, int qos, boolean retained) {
        MqttMessage message = new MqttMessage();
        System.out.println(Charset.defaultCharset());
        try{
            message.setPayload(pushMessage.getBytes("UTF-8"));
        }
        catch(Exception e){
            System.out.println("MQTT消息使用默认编码");
            System.out.println(Charset.defaultCharset());
            message.setPayload(pushMessage.getBytes());
        }
        message.setQos(qos);
        message.setRetained(retained);
        MqttTopic mqttTopic = JwMqttClient.getClient().getTopic(topic);
        if (null == mqttTopic) {
            LOGGER.error("topic is not exist");
        }
        MqttDeliveryToken token;//Delivery:配送
        synchronized (this) {//注意：这里一定要同步，否则，在多线程publish的情况下，线程会发生死锁，分析见文章最后补充
            try {
                token = mqttTopic.publish(message);//也是发送到执行队列中，等待执行线程执行，将消息发送到消息中间件
                token.waitForCompletion(1000L);
            } catch (MqttPersistenceException e) {
                e.printStackTrace();
            } catch (MqttException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 订阅某个主题
     *
     * @param topic
     * @param qos
     */
    public void subscribe(String topic, int qos) {
        try {
            JwMqttClient.getClient().subscribe(topic, qos);
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }

    /**
     * 取消订阅主题
     *
     * @param topic 主题名称
     */
    public void cleanTopic(String topic) {
        if (client != null && client.isConnected()) {
            try {
                client.unsubscribe(topic);
            } catch (MqttException e) {
                e.printStackTrace();
            }
        } else {
            System.out.println("取消订阅失败！");
        }
    }
}
消息实体
package com.jqxx.digtwinresop.module.equipment.mqtt;

public class JwMqttMessage {
    private String topic;
    private String content;
    private String time;

    public String getTopic() {
        return topic;
    }
    public void setTopic(String topic) {
        this.topic = topic;
    }

    public String getContent() {
        return content;
    }
    public void setContent(String content) {
        this.content = content;
    }

    public String getTime() {
        return time;
    }
    public void setTime(String time) {
        this.time = time;
    }
    @Override
    public String toString(){
        return "JsonStr";
        //        return JSON.toJSONString(this);
    }
}
MQTT配置
package com.jqxx.digtwinresop.module.equipment.mqtt;

import org.eclipse.paho.client.mqttv3.MqttException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MQTTConfig {
    private static final Logger log = LoggerFactory.getLogger(MQTTConfig.class);
    @Value("${mqtt.host}")
    String host;
    @Value("${mqtt.userName}")
    String username;
    @Value("${mqtt.password}")
    String password;
    @Value("${mqtt.clientId}")
    String clientId;
    @Value("${mqtt.timeout}")
    int timeOut;
    @Value("${mqtt.keepalive}")
    int keepAlive;

    @Bean//注入spring
    public JwMqttClient jwMqttClient() {
        JwMqttClient jwMqttClient = new JwMqttClient(host, username, password, clientId, timeOut, keepAlive);
        for (int i = 0; i < 10; i++) {
            try {
                jwMqttClient.connect();
                //不同的主题
               jwMqttClient.subscribe(MqttConstants.TOPIC_DXGIS, 1);
//               jwMqttClient.subscribe(MqttConstants.TOPIC_DXGIS_APP, 1);
//               jwMqttClient.subscribe(MqttConstants.TOPIC_WL_IOT_ONLINE, 1);
//               jwMqttClient.subscribe(MqttConstants.TOPIC_WL_IOT_MONITOR, 1);
                return jwMqttClient;
            } catch (MqttException e) {
                log.error("MQTT connect exception,connect time = " + i);
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e1) {
                    e1.printStackTrace();
                }
            }
        }
        return jwMqttClient;
    }

    public String getHost() {
        return host;
    }

    public void setHost(String host) {
        this.host = host;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getClientId() {
        return clientId;
    }

    public void setClientId(String clientId) {
        this.clientId = clientId;
    }

    public int getTimeOut() {
        return timeOut;
    }

    public void setTimeOut(int timeOut) {
        this.timeOut = timeOut;
    }

    public int getKeepAlive() {
        return keepAlive;
    }

    public void setKeepAlive(int keepAlive) {
        this.keepAlive = keepAlive;
    }
}
MQTT主题枚举
package com.jqxx.digtwinresop.module.equipment.mqtt;

/**
 * @author wll
 * date 2024/3/12
 */
public class MqttConstants {

    public static final String TOPIC_DXGIS = "dp";//大屏队列

    public static final String EQUIPMENT_DIRECT_EXCHANGE = "equipment_direct_exchange";//大屏Direct交换机

    public static final String EQUIPMENT_QUEUE_BIDING = "dp";//大屏

}

依赖：

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