代码收藏家技术教程 2023-03-14

《从环境搭建到服务集成：深入浅出Springboot整合MQTT》

介绍

Eclipse Mosquitto是一个开源消息代理，实现了MQTT协议版本3.1和3.1.1。Mosquitto轻量，适用于低功耗单板计算机到完整服务器的所有设备。Mosquitto项目还提供了用于实现MQTT客户端的C库以及非常受欢迎的mosquitto_pub和mosquitto_sub命令行MQTT客户端。

Ubuntu安装mosquitto

1.安装mosquitto

sudo apt-get install mosquitto

2.查看mosquitto服务状态

sudo service mosquitto status

3.开启/停止 mosquitto服务

sudo service mosquitto start

sudo service mosquitto stop

4.配置mosquitto服务器用户验证

①进入mosquitto目录

cd /etc/mosquitto/

②修改mosquitto.conf

sudo vim mosquitto.conf

③mosquitto配置用户验证信息

#不允许匿名

allow_anonymous false

#配置用户密码文件

password_file /etc/mosquitto/pwfile

#开放端口，允许所有IP访问
listener 1883 0.0.0.0

④配置用户登录名及密码

sudo mosquitto_passwd -c /etc/mosquitto/pwfile 用户名

用户名填写自己想要的名称，然后输入两遍密码，用户名和密码就添加成功了

Springboot 集成 MQTT服务

1.在Pom.xml里导入mqtt的jar包

<dependency>
    <groupId>org.eclipse.paho</groupId>
    <artifactId>org.eclipse.paho.client.mqttv3</artifactId>
    <version>1.2.2</version>
</dependency>

2.在application.yml配置文件里配置MQTT服务器的连接信息

mqtt:
  userName: admin
  passWord: 123456
  host: tcp://192.168.145.128:1883
  topics: /txt/a,/txt/b,/txt/c

3.新建一个初始化MQTT连接的class

①通过Value注解从配置文件获取MQTT配置信息

	//MQTT服务器用户名
    @Value("${mqtt.userName}")
    private String userName;
    //MQTT服务器密码
    @Value("${mqtt.passWord}")
    private String passWord;
    //MQTT服务器的IP地址和端口
    @Value("${mqtt.host}")
    private String host;
    //所要订阅的Topic列表,topic列表通过逗号进行分割
    @Value("${mqtt.topics}")
    private List<String> sub_Topic;

②配置MQTT连接信息

	/**
     * 配置MQTT连接信息
     * @return
     */
    public MqttConnectOptions getOptions(){
        MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
        //是否清除Session
        mqttConnectOptions.setCleanSession(false);
        //MQTT服务器用户名
        mqttConnectOptions.setUserName(userName);
        //MQTT服务器密码
        mqttConnectOptions.setPassword(passWord.toCharArray());
        //MQTT连接超时时间,10s
        mqttConnectOptions.setConnectionTimeout(10);
        //设置MQTT心跳时间,20s
        mqttConnectOptions.setKeepAliveInterval(20);
        return mqttConnectOptions;
    }

③连接MQTT服务端

	/**
     * 连接MQTT服务端
     */
    public void connect(){
        //防止重复创建MQTTClient实例
        if (mqttClient == null){
            try {
                mqttClient = new MqttClient(host,clientId,new MemoryPersistence());
                //MqttDataService是接收订阅topic数据推送的回调
                mqttClient.setCallback(new MqttDataService());
            } catch (MqttException e) {
                e.printStackTrace();
            }
        }
        MqttConnectOptions options = getOptions();
        //判断拦截状态
        if (!mqttClient.isConnected()){
            try {
                mqttClient.connect(options);
                log.info("[MQTT] 连接成功！");
            } catch (MqttException e) {
                e.printStackTrace();
            }
        }else {
            try {
                mqttClient.disconnect();
                mqttClient.connect(options);
                log.info("[MQTT] 连接成功！");
            } catch (MqttException e) {
                e.printStackTrace();
            }
        }
    }

④发送消息

	/**
     * 发送数据
     */
    public void publish(String topic, String content) throws MqttException {
        MqttMessage message = new MqttMessage(content.getBytes());
        try{
            mqttClient.publish(topic, message);
        }catch (Exception e){
            e.printStackTrace();
        }
    }

⑤断线重连

	/**
     *断线重连
     */
    public void reConnect() throws MqttException {
        if (null != mqttClient){
            MqttConnectOptions options = getOptions();
            mqttClient.connect(options);
            log.info("[MQTT] 重连成功！");
        }
    }

⑥启动程序并订阅Topic

	/**
     * 启动程序并订阅Topic
     * @PostConstruct 注解的作用是服务初始化启动完成后会主动执行有该注解的方法
     */
    @PostConstruct
    public void start(){
        log.info("MQTT连接数据初始化成功，开始连接....");
        try {
            connect();
            for (int i = 0;i<sub_Topic.size();i++){
                mqttClient.subscribe(sub_Topic.get(i),1);
            }
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }

⑦MqttConfigService.class

package com.example.mqtttest.service;

import lombok.extern.slf4j.Slf4j;
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;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;
import java.util.List;
import java.util.UUID;

@Service
@Slf4j
public class MqttConfigService {

    //mqtt连接
    private MqttClient mqttClient;
    //MQTT服务器用户名
    @Value("${mqtt.userName}")
    private String userName;
    //MQTT服务器密码
    @Value("${mqtt.passWord}")
    private String passWord;
    //MQTT服务器的IP地址和端口
    @Value("${mqtt.host}")
    private String host;
    //所要订阅的Topic列表,topic列表通过逗号进行分割
    @Value("${mqtt.topics}")
    private List<String> sub_Topic;
    private String clientId = createUUID();

    /**
     * 配置MQTT连接信息
     * @return
     */
    public MqttConnectOptions getOptions(){
        MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
        //是否清除Session
        mqttConnectOptions.setCleanSession(false);
        //MQTT服务器用户名
        mqttConnectOptions.setUserName(userName);
        //MQTT服务器密码
        mqttConnectOptions.setPassword(passWord.toCharArray());
        //MQTT连接超时时间,10s
        mqttConnectOptions.setConnectionTimeout(10);
        //设置MQTT心跳时间,20s
        mqttConnectOptions.setKeepAliveInterval(20);
        return mqttConnectOptions;
    }

    /**
     * 连接MQTT服务端
     */
    public void connect(){
        //防止重复创建MQTTClient实例
        if (mqttClient == null){
            try {
                mqttClient = new MqttClient(host,clientId,new MemoryPersistence());
                //MqttDataService是接收订阅topic数据推送的回调
                mqttClient.setCallback(new MqttDataService());
            } catch (MqttException e) {
                e.printStackTrace();
            }
        }
        MqttConnectOptions options = getOptions();
        //判断拦截状态
        if (!mqttClient.isConnected()){
            try {
                mqttClient.connect(options);
                log.info("[MQTT] 连接成功！");
            } catch (MqttException e) {
                e.printStackTrace();
            }
        }else {
            try {
                mqttClient.disconnect();
                mqttClient.connect(options);
                log.info("[MQTT] 连接成功！");
            } catch (MqttException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 启动程序并订阅Topic
     * @PostConstruct 注解的作用是服务初始化启动完成后会主动执行有该注解的方法
     */
    @PostConstruct
    public void start(){
        log.info("MQTT连接数据初始化成功，开始连接....");
        try {
            connect();
            for (int i = 0;i<sub_Topic.size();i++){
                mqttClient.subscribe(sub_Topic.get(i),1);
            }
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }

    /**
     * 发送数据
     */
    public void publish(String topic, String content) throws MqttException {
        MqttMessage message = new MqttMessage(content.getBytes());
        try{
            mqttClient.publish(topic, message);
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    /**
     *断线重连
     */
    public void reConnect() throws MqttException {
        if (null != mqttClient){
            MqttConnectOptions options = getOptions();
            mqttClient.connect(options);
            log.info("[MQTT] 重连成功！");
        }
    }


    public static String createUUID(){
        UUID uuid = UUID.randomUUID();
        String uuidStr = String.valueOf(uuid);
        String uuidStr2 = uuidStr.replaceAll("-","");
        return uuidStr2;
    }
}

4.实现MqttCallback回调类

package com.example.mqtttest.service;

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.MqttMessage;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

/**
 * 实现MqttCallback回调类
 */
@Slf4j
public class MqttDataService  implements MqttCallback {

     private MqttConfigService mqttConfigService = ActivitiConfig.getBean(MqttConfigService.class);

    /**
     * 与MQTT服务器连接断开后的回调
     * @param throwable
     */
    @Override
    public void connectionLost(Throwable throwable) {
        // 连接丢失后，一般在这里面进行重连
        log.info("[MQTT] 连接断开，10S之后尝试重连...");
        while (true){
            try {
                Thread.sleep(10000);
                mqttConfigService.reConnect();
                break;
            }catch (Exception e){
                e.printStackTrace();
                continue;
            }
        }
    }

    /**
     * 接收所订阅Topic推送的消息
     * @param topic
     * @param mqttMessage
     * @throws Exception
     */
    @Override
    public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
        String result = mqttMessage.toString();
        log.info("#####接收到的数据："+result);
    }

    @Override
    public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {

    }
}

5.所订阅Topic推送的数据

#####接收到的数据：
{
  "msg": "hello"
}

6.使用publish方法发送数据到指定的Topic

①编写测试方法

	@Test
    public void test(){
        mqttConfigService.publish("/test/d","数据发送成功");
    }

②使用MQTT客户端工具订阅该Topic：/test/d，客户端工具接收到我们发送的数据

7.MqttDataService的接收消息方法如果接收的数据处理抛出异常，会导致MQTT连接异常断开

①处理数据的方法抛出异常

②MQTT连接异常退出

③解决方法：采用异步的方法，将数据交由其他线程处理

该例子仅作测试，正常应采用线程池方式去做异步处理。

8.不通过@Autowired或@Resource注解获取JavaBean的方式

package com.example.mqtttest.service;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.Configuration;

@Configuration
public class ActivitiConfig implements ApplicationContextAware {
    static ApplicationContext applicationContext;
    public static <T> T getBean(Class<T> clazz) {
        return applicationContext.getBean(clazz);
    }
    @Override
    public void setApplicationContext(ApplicationContext arg0) throws BeansException {
        if (applicationContext == null){
            applicationContext = arg0;
        }
    }
}