手写Mqtt工具类到手写Mqtt-Starter启动器-简单优雅集成Mqtt

  • Java大飞哥

    2024-01-30 11:39:38
  • 数据库开发技术
  • 原创

1.集成方式对比

1.1使用spring-integration-mqtt

依赖如下：


    org.springframework.integration
    spring-integration-mqtt
    5.1.8.RELEASE
    
        
            org.eclipse.paho
            org.eclipse.paho.client.mqttv3
        
    


    org.eclipse.paho
    org.eclipse.paho.client.mqttv3
    1.2.2
这个是spring提供的一个对mqtt进行封装的一个依赖，底层是对org.eclipse.paho.client.mqttv3进行了二次封装，说实话，spring的这个操作有点过度封装了，spring的东西好用，但是有的确实是过度封装了，给人赶脚复杂不好用就是过度封装，一点也不轻量级，所以我个人觉得有些还是自己封装一个轻量级的工具类完全是够用的，不用搞的那么花里胡哨的，没啥鸟用，都是殊途同归。


1.2使用org.eclipse.paho.client.mqttv3

依赖如下：

     org.eclipse.paho
     org.eclipse.paho.client.mqttv3
    1.2.5
这个是EMQX官网推荐的一个方式，直接使用这个依赖，代码也比较简单，EMQX官网有demo。


2.环境准备

开源大规模分布式MQTT消息服务器EMQX部署教程
https://mp.weixin.qq.com/s/f4gFS0F5sEKBSJYZFCDMuw
环境准备可以参看之前一篇文章，文章链接我已经放在上面了。


3.手写Mqtt工具类

需要引入上面1.2的org.eclipse.paho.client.mqttv3这个依赖
废话不多说直接上代码

3.1yaml配置

yaml配置如下：
mqtt:  mps:    # 多个brokers用,分割即可：如：xxx1,xxx2,,,下面两个配置的是同一个topic,所以往这个topic上发送消息,这个两个client会收到消息,订阅会打收到两条一样的消息日志，生产一般设置不同的topic    - brokers: tcp://192.168.40.47:1883      userName: zlf1      password: xxxx1 #明文      clientId: zlf1_publish      topic: mqtt/test      qos: 2      type: publish    - brokers: tcp://192.168.40.47:1883      userName: zlf2      password: xxxx2 #明文      clientId: zlf2_subscribe      topic: mqtt/test      qos: 2      type: subscribe


3.2代码

MqttProperties类如下
package xxxxx.config;
import lombok.Data;
import java.util.List;
/** * 其它属性默认即可,可以抽成配置类的参数 */@Datapublic class MqttProperties {
    /**     * mqtt服务器地址列表     */    private List<String> brokers;
    /**     * 用户名     */    private String userName;
    /**     * 密码     */    private String password;
    /**     * 客户端clientId     */    private String clientId;
    /**     * 主题     */    private String topic;
    /**     * 消息等级     * QoS 0：最多交付一次，消息可能丢失。     * QoS 1：至少交付一次，消息可以保证到达，但是可能重复到达。     * QoS 2：只交付一次，消息保证到达，并且不会重复。     */    private Integer qos;
    /**     * 类型：只支持下面两种类型,如果要支持发布和订阅可以配置多个,只不过类型不一样而已     * publish 发布     * subscribe 订阅     */    private String type;
}
MqttConfig类如下
package xxxxx.config;
import lombok.Data;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.context.annotation.Configuration;
import java.util.List;
@Data@Configuration@ConfigurationProperties(prefix = "mqtt")public class MqttConfig {
    private List<MqttProperties> mps;
}
MqttUtil工具类如下：
package xxxxx.util;
import lombok.extern.slf4j.Slf4j;import org.apache.commons.collections4.CollectionUtils;import org.apache.commons.lang3.StringUtils;import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;import org.eclipse.paho.client.mqttv3.IMqttMessageListener;import org.eclipse.paho.client.mqttv3.MqttCallback;import org.eclipse.paho.client.mqttv3.MqttClient;import org.eclipse.paho.client.mqttv3.MqttConnectOptions;import org.eclipse.paho.client.mqttv3.MqttMessage;import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
import java.util.List;import java.util.Objects;import java.util.concurrent.ConcurrentHashMap;
/** * 可以搞成一个start启动器,根据配置类来实例化一个MqttClient注入一个bean,让spring来管理这个对象 * 方法的参数太长,可以搞成一个配置类或者使用一个类的对象封装承接下的， * 让代码更具有封装性, * 可不可以先订阅后去发布,答案是可以 */@Slf4jpublic class MqttUtil {
    /**     * 项目启动就要将client建立连接和订阅建立好,     * 然后项目中用的时候才不会由于第一次建立连接和第一次发布消息,未建立订阅而导致第一次发布的消息丢失     * 这个问题可以先订阅后发布就可以避免这个问题了     */    private static final ConcurrentHashMap<String, MqttClient> clientMap = new ConcurrentHashMap<>();
    public static MqttClient createMqttClient(String broker, String userName, String password, String clientId) {        if (StringUtils.isBlank(broker)) {            throw new RuntimeException("createMqttClient Broker must not be empty");        }        if (StringUtils.isBlank(userName)) {            throw new RuntimeException("createMqttClient userName must not be empty");        }        if (StringUtils.isBlank(password)) {            throw new RuntimeException("createMqttClient Password must not be empty");        }        if (StringUtils.isBlank(clientId)) {            throw new RuntimeException("createMqttClient ClientId must not be empty");        }        if (clientMap.containsKey(clientId)) {            return clientMap.get(clientId);        }        MqttClient client = null;        try {            client = new MqttClient(broker, clientId, new MemoryPersistence());            MqttConnectOptions options = new MqttConnectOptions();            options.setUserName(userName);            options.setPassword(password.toCharArray());            //一下三个参数有默认值不用设置            //options.setCleanSession();            //options.setKeepAliveInterval();            //options.setConnectionTimeout();            // 设置 socket factory            /*            TLS/SSL 连接            String caFilePath = "/cacert.pem";            String clientCrtFilePath = "/client.pem";            String clientKeyFilePath = "/client.key";            SSLSocketFactory socketFactory = getSocketFactory(caFilePath, clientCrtFilePath, clientKeyFilePath, "");            options.setSocketFactory(socketFactory);            */            options.setAutomaticReconnect(true);            client.connect(options);            clientMap.put(clientId, client);        } catch (Exception e) {            log.error("创建MqttClient异常:{}", e.getMessage());        }        return client;    }
    public static MqttClient createMqttClient2(List<String> brokers, String userName, String password, String clientId) {        if (CollectionUtils.isEmpty(brokers)) {            throw new RuntimeException("createMqttClient2 Broker must not be empty");        }        if (StringUtils.isBlank(userName)) {            throw new RuntimeException("createMqttClient2 userName must not be empty");        }        if (StringUtils.isBlank(password)) {            throw new RuntimeException("createMqttClient2 Password must not be empty");        }        if (StringUtils.isBlank(clientId)) {            throw new RuntimeException("createMqttClient2 ClientId must not be empty");        }        if (clientMap.containsKey(clientId)) {            return clientMap.get(clientId);        }        MqttClient client = null;        try {            client = new MqttClient(brokers.get(0), clientId, new MemoryPersistence());            MqttConnectOptions options = new MqttConnectOptions();            options.setUserName(userName);            options.setPassword(password.toCharArray());            //以下三个参数有默认值不用设置            //options.setCleanSession();            //options.setKeepAliveInterval();            //options.setConnectionTimeout();            // 设置 socket factory            /*            TLS/SSL 连接            String caFilePath = "/cacert.pem";            String clientCrtFilePath = "/client.pem";            String clientKeyFilePath = "/client.key";            SSLSocketFactory socketFactory = getSocketFactory(caFilePath, clientCrtFilePath, clientKeyFilePath, "");            options.setSocketFactory(socketFactory);            */            options.setAutomaticReconnect(true);            options.setServerURIs(brokers.toArray(new String[brokers.size()]));            client.connect(options);            clientMap.put(clientId, client);        } catch (Exception e) {            log.error("创建MqttClient异常:{}", e.getMessage());        }        return client;    }
    public static MqttMessage createMessage(String topic, Integer qos, String content) {        // 创建消息并设置 QoS        MqttMessage message = new MqttMessage(content.getBytes());        if (Objects.isNull(qos)) {            //默认是1            qos = 1;            message.setQos(qos);        } else {            message.setQos(qos);        }        return message;    }
    public static void publish(MqttClient client, String topic, MqttMessage message) {        if (Objects.isNull(client)) {            throw new RuntimeException("publish client must not be null");        }        if (StringUtils.isBlank(topic)) {            throw new RuntimeException("publish topic must");        }        if (Objects.isNull(message)) {            throw new RuntimeException("message must not be null");        }        if (message.getPayload().length == 0) {            throw new RuntimeException("public message is empty");        }        try {            client.publish(topic, message);            //这里不用关闭这个客户端和连接            // 关闭连接            //client.disconnect();            // 关闭客户端            //client.close();        } catch (Exception e) {            log.error("publish error:{}", e.getMessage());        }    }
    public static void subscribe(MqttClient client, String topic, Integer qos) {        if (Objects.isNull(client)) {            throw new RuntimeException("publish client is null");        }        if (StringUtils.isBlank(topic)) {            throw new RuntimeException("publish topic is empty");        }        if (Objects.isNull(qos)) {            qos = 1;        }        try {            // 设置回调            client.setCallback(new MqttCallback() {
                public void connectionLost(Throwable cause) {                    log.error("connectionLost:{}", cause.getMessage());                }
                public void messageArrived(String topic, MqttMessage message) {                    String msg = new String(message.getPayload());                    int qos1 = message.getQos();                    log.info("subscribe topic:{}", topic);                    log.info("subscribe Qos:{}", qos1);                    log.info("subscribe msg:{}", msg);                    //新增业务拓展接口对接或者可以发送springEvent事件消息，然后监听该消息即可                }
                public void deliveryComplete(IMqttDeliveryToken token) {                    log.info("delivery complete:{}", token.isComplete());                }
            });            client.subscribe(topic, qos);        } catch (Exception e) {            log.error("subscribe error:{}", e.getMessage());        }    }
    public static void subscribe2(MqttClient client, String topic, Integer qos, MqttCallback mqttCallback) {        if (Objects.isNull(client)) {            throw new RuntimeException("publish client is null");        }        if (StringUtils.isBlank(topic)) {            throw new RuntimeException("publish topic is empty");        }        if (Objects.isNull(qos)) {            qos = 1;        }        try {            // 设置回调            client.setCallback(mqttCallback);            client.subscribe(topic, qos);        } catch (Exception e) {            log.error("subscribe error:{}", e.getMessage());        }    }
    public static void publish2(String broker, String username, String password, String clientId, String topic, String content, Integer qos) {        MqttClient mqttClient = MqttUtil.createMqttClient(broker, username, password, clientId);        MqttMessage message = MqttUtil.createMessage(topic, qos, content);        MqttUtil.publish(mqttClient, topic, message);    }
    public static void subscribe3(String broker, String username, String password, String clientId, String topic, Integer qos) {        MqttClient mqttClient = MqttUtil.createMqttClient(broker, username, password, clientId);        MqttUtil.subscribe(mqttClient, topic, qos);    }
    public static void subscribe4(String broker, String username, String password, String clientId, String topic, Integer qos, MqttCallback mqttCallback) {        MqttClient mqttClient = MqttUtil.createMqttClient(broker, username, password, clientId);        MqttUtil.subscribe2(mqttClient, topic, qos, mqttCallback);    }
    public static void subscribe5(MqttClient client, String topic, Integer qos, IMqttMessageListener messageListener) {        if (Objects.isNull(client)) {            throw new RuntimeException("publish5 client is null");        }        if (StringUtils.isBlank(topic)) {            throw new RuntimeException("publish5 topic is empty");        }        if (Objects.isNull(qos)) {            qos = 1;        }        try {            client.subscribe(topic, qos, messageListener);        } catch (Exception e) {            log.error("subscribe5 error:{}", e.getMessage());        }    }
    public static void subscribe6(String broker, String username, String password, String clientId, String topic, Integer qos, IMqttMessageListener messageListener) {        MqttClient mqttClient = MqttUtil.createMqttClient(broker, username, password, clientId);        MqttUtil.subscribe5(mqttClient, topic, qos, messageListener);    }
    public static void unsubscribe(MqttClient mqttClient, String topic) {        if (Objects.isNull(mqttClient)) {            throw new RuntimeException("unsubscribe mqttClient is not null");        }        if (StringUtils.isBlank(topic)) {            throw new RuntimeException("unsubscribe topic is not empty");        }        try {            mqttClient.unsubscribe(topic);        } catch (Exception e) {            log.error("unsubscribe error:{}", e.getMessage());        }    }
}
SSLUtils类如下：
package xxxxx.util;
import org.bouncycastle.jce.provider.BouncyCastleProvider;import org.bouncycastle.openssl.PEMKeyPair;import org.bouncycastle.openssl.PEMParser;import org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter;
import javax.net.ssl.KeyManagerFactory;import javax.net.ssl.SSLContext;import javax.net.ssl.SSLSocketFactory;import javax.net.ssl.TrustManagerFactory;import java.io.BufferedInputStream;import java.io.FileInputStream;import java.io.FileReader;import java.security.KeyPair;import java.security.KeyStore;import java.security.Security;import java.security.cert.CertificateFactory;import java.security.cert.X509Certificate;
public class SSLUtils {
    public static SSLSocketFactory getSocketFactory(final String caCrtFile,                                                    final String crtFile, final String keyFile, final String password)            throws Exception {        Security.addProvider(new BouncyCastleProvider());
        // load CA certificate        X509Certificate caCert = null;
        FileInputStream fis = new FileInputStream(caCrtFile);        BufferedInputStream bis = new BufferedInputStream(fis);        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        while (bis.available() > 0) {            caCert = (X509Certificate) cf.generateCertificate(bis);        }
        // load client certificate        bis = new BufferedInputStream(new FileInputStream(crtFile));        X509Certificate cert = null;        while (bis.available() > 0) {            cert = (X509Certificate) cf.generateCertificate(bis);        }
        // load client private key        PEMParser pemParser = new PEMParser(new FileReader(keyFile));        Object object = pemParser.readObject();        JcaPEMKeyConverter converter = new JcaPEMKeyConverter().setProvider("BC");        KeyPair key = converter.getKeyPair((PEMKeyPair) object);        pemParser.close();
        // CA certificate is used to authenticate server        KeyStore caKs = KeyStore.getInstance(KeyStore.getDefaultType());        caKs.load(null, null);        caKs.setCertificateEntry("ca-certificate", caCert);        TrustManagerFactory tmf = TrustManagerFactory.getInstance("X509");        tmf.init(caKs);
        // client key and certificates are sent to server so it can authenticate        KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());        ks.load(null, null);        ks.setCertificateEntry("certificate", cert);        ks.setKeyEntry("private-key", key.getPrivate(), password.toCharArray(),                new java.security.cert.Certificate[]{cert});        KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory                .getDefaultAlgorithm());        kmf.init(ks, password.toCharArray());
        // finally, create SSL socket factory        SSLContext context = SSLContext.getInstance("TLSv1.2");        context.init(kmf.getKeyManagers(), tmf.getTrustManagers(), null);
        return context.getSocketFactory();    }
}
MqttApplicationAware类如下：
package xxxx.config;
import com.alibaba.fastjson.JSON;import xxxxxx.MqttUtil;import lombok.extern.slf4j.Slf4j;import org.apache.commons.collections4.CollectionUtils;import org.eclipse.paho.client.mqttv3.MqttClient;import org.springframework.beans.BeansException;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;import org.springframework.stereotype.Component;
import java.util.List;
@Component@Slf4jpublic class MqttApplicationAware implements ApplicationContextAware {
    @Autowired    private MqttConfig mqttConfig;
    @Override    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {        log.info("==========Mqtt启动初始化开始===========");        List<MqttProperties> mps = mqttConfig.getMps();        if (CollectionUtils.isNotEmpty(mps)) {            for (MqttProperties mp : mps) {                log.info("==========Mqtt启动初始化配置:{}==========", JSON.toJSONString(mp));                MqttClient mqttClient = MqttUtil.createMqttClient2(mp.getBrokers(), mp.getUserName(), mp.getPassword(), mp.getClientId());                if ("subscribe".equals(mp.getType())) {                    MqttUtil.subscribe(mqttClient, mp.getTopic(), mp.getQos());                    log.info("==========Mqtt启动初始化订阅配置完成==========");                }            }        }        log.info("==========Mqtt启动初始化结束===========");    }
}
MqttController类如下：
package xxxx.controller;
import com.dytz.barrier.gate.web.util.MqttUtil;import lombok.extern.slf4j.Slf4j;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.RestController;
@Slf4j@RestController@RequestMapping("mqtt")public class MqttController {        @GetMapping("/pubMsg")    public String pubMsg(@RequestParam(value = "msg") String msg) {        String broker = "tcp://192.168.40.47:1883";        String username = "zlf1";        String password = "xxxx1明文";        String clientId = "zlf1_publish";        String topic = "mqtt/test";        MqttUtil.publish2(broker, username, password, clientId, topic, msg, 2);        return "ok";    }
}


3.3测试验证

将redis、emqx启动好，然后进行测试验证，使用ApiPostman或者是Apifox进行接口请求：

调用接口后订阅了mqtt/test主题的客户端可以收到消息：

EMQX后台：

客户端：

订阅管理：

主题监控：


4.手写Mqtt-Start启动器

废话不多说直接上代码

4.1使用说明

  1. 项目中引入依赖如下：

<dependency>     <groupId>org.zlfgroupId>     <artifactId>mqtt-spring-boot-startartifactId>     <version>1.0-SNAPSHOTversion> dependency>

  2. nacos配置如下：

mqtt:  mps:    # 多个brokers用,分割即可：如：xxx1,xxx2,,,下面两个配置的是同一个topic,所以往这个topic上发送消息,这个两个client会收到消息,订阅会打收到两条一样的消息日志，生产一般设置不同的topic    - brokers: tcp://192.168.40.47:1883      userName: zlf1      password: xxx1      clientId: zlf1_publish      topic: mqtt/test      qos: 2      type: publish    - brokers: tcp://192.168.40.47:1883      userName: zlf2      password: xxx2      clientId: zlf2_subscribe      topic: mqtt/test      qos: 2      type: subscribe

3. 启动类上加入如下注解：

3.1 @Import(value = {MqttApplicationAware.class, MqttApiService.class, MqttSpringUtils.class}) //导入相关的类3.2 @EnableMqtt //开启Mqtt


4.2项目工程结构

yaml的配置类用的也是上面工具类的那个配置类，一模一样的配置
项目工程结构：


4.3代码

config下的配置类用的也是上面Mqtt工具类的那两个配置类的，这里重点讲解下这个starter下的这几个类：
EnableMqtt启动mqtt集成注解：
package com.zlf.starter;
import org.springframework.context.annotation.Import;
import java.lang.annotation.Documented;import java.lang.annotation.ElementType;import java.lang.annotation.Inherited;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;
/** * 使用需要在启动类上加入@EnableMqtt注解 * 和 @Import(value = {MqttApplicationAware.class, MqttApiService.class,MqttSpringUtils.class}) * @author zlf */@Target(ElementType.TYPE)@Retention(RetentionPolicy.RUNTIME)@Documented@Inherited@Import(MqttClientRegistrar.class)public @interface EnableMqtt {
}
MqttClientRegistrar类如下，将MqttClient和连接交给spring容器管理
package com.zlf.starter;
import com.zlf.config.MqttConfig;import com.zlf.config.MqttProperties;import lombok.SneakyThrows;import lombok.extern.slf4j.Slf4j;import org.apache.commons.collections4.CollectionUtils;import org.apache.commons.lang3.StringUtils;import org.eclipse.paho.client.mqttv3.MqttClient;import org.eclipse.paho.client.mqttv3.MqttConnectOptions;import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;import org.springframework.beans.MutablePropertyValues;import org.springframework.beans.factory.config.ConstructorArgumentValues;import org.springframework.beans.factory.support.BeanDefinitionRegistry;import org.springframework.beans.factory.support.RootBeanDefinition;import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.boot.context.properties.EnableConfigurationProperties;import org.springframework.boot.context.properties.bind.Binder;import org.springframework.context.EnvironmentAware;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;import org.springframework.core.annotation.AnnotationUtils;import org.springframework.core.env.Environment;import org.springframework.core.type.AnnotationMetadata;
import java.util.List;import java.util.Objects;
/** * @author zlf */@Slf4j@Configuration@ConditionalOnClass(MqttClient.class)@EnableConfigurationProperties(MqttConfig.class)public class MqttClientRegistrar implements ImportBeanDefinitionRegistrar, EnvironmentAware {
    private MqttConfig mqttConfig;
    public static final String MQTT_OPS_PREFIX = "mqtt-ops-";
    @SneakyThrows    @Override    public void registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry beanDefinitionRegistry) {        List<MqttProperties> mps = mqttConfig.getMps();        if (CollectionUtils.isEmpty(mps)) {            throw new RuntimeException("mqtt配置不为空,请检查配置!");        }        for (MqttProperties m : mps) {            ConstructorArgumentValues cas = new ConstructorArgumentValues();            if (CollectionUtils.isEmpty(m.getBrokers())) {                throw new RuntimeException("MqttClient Broker must not be empty");            }            if (StringUtils.isBlank(m.getUserName())) {                throw new RuntimeException("MqttClient userName must not be empty");            }            if (StringUtils.isBlank(m.getPassword())) {                throw new RuntimeException("MqttClient Password must not be empty");            }            if (StringUtils.isBlank(m.getClientId())) {                throw new RuntimeException("MqttClient ClientId must not be empty");            }            cas.addIndexedArgumentValue(0, m.getBrokers().get(0));            cas.addIndexedArgumentValue(1, m.getClientId());            cas.addIndexedArgumentValue(2, new MemoryPersistence());            MutablePropertyValues values = new MutablePropertyValues();            // 注册bean            RootBeanDefinition clientBeanDefinition = new RootBeanDefinition(MqttClient.class, cas, values);            beanDefinitionRegistry.registerBeanDefinition(m.getClientId(), clientBeanDefinition);
            MutablePropertyValues values2 = new MutablePropertyValues();            values2.addPropertyValue("userName", m.getUserName());            values2.addPropertyValue("password", m.getPassword().toCharArray());            values2.addPropertyValue("automaticReconnect", true);            RootBeanDefinition optionsBeanDefinition = new RootBeanDefinition(MqttConnectOptions.class, null, values2);            beanDefinitionRegistry.registerBeanDefinition(MQTT_OPS_PREFIX + m.getClientId(), optionsBeanDefinition);            //一下三个参数有默认值不用设置(按需设置)            //options.setCleanSession();            //options.setKeepAliveInterval();            //options.setConnectionTimeout();            // 设置 socket factory            /*            TLS/SSL 连接 (按需设置)            String caFilePath = "/cacert.pem";            String clientCrtFilePath = "/client.pem";            String clientKeyFilePath = "/client.key";            SSLSocketFactory socketFactory = getSocketFactory(caFilePath, clientCrtFilePath, clientKeyFilePath, "");            options.setSocketFactory(socketFactory);            */        }    }
    @Override    public void setEnvironment(Environment environment) {        // 通过Binder将environment中的值转成对象        mqttConfig = Binder.get(environment).bind(getPropertiesPrefix(MqttConfig.class), MqttConfig.class).get();    }
    private String getPropertiesPrefix(Class tClass) {        return Objects.requireNonNull(AnnotationUtils.getAnnotation(tClass, ConfigurationProperties.class)).prefix();    }
}
MqttApplicationAware类如下，在容器启动后将MqttClient和连接进行管理，让客户端跟EMQX服务器建立连接，处理主题订阅：
package com.zlf.starter;
import com.alibaba.fastjson.JSON;import com.zlf.config.MqttConfig;import com.zlf.config.MqttProperties;import com.zlf.event.MessageArrivedEvent;import lombok.extern.slf4j.Slf4j;import org.apache.commons.collections4.CollectionUtils;import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;import org.eclipse.paho.client.mqttv3.MqttCallback;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.springframework.beans.BeansException;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;import org.springframework.stereotype.Component;
import java.util.List;
/** * @author zlf * 下面注释的代码是可以和MqttConfig、MqttProperties、MqttUtil工具类配置使用,其它代码删除即可， * 由于做成一个start启动器可以直接使用,不用MqttUtil工具， * MqttUtil可以单独使用不依赖以nacos相关的依赖，该start也可以不依赖nacos相关依赖, * 不依赖于nacos的配置动态感知刷新可以移除@RefreshScope相关的主机即可。 * 配置信息从项目的配置文件中读取即可 */@Component@Slf4jpublic class MqttApplicationAware implements ApplicationContextAware {
    @Override    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {        log.info("==========Mqtt启动初始化开始===========");        MqttConfig mqttConfig = applicationContext.getBean(MqttConfig.class);        List mps = mqttConfig.getMps();        if (CollectionUtils.isNotEmpty(mps)) {            for (MqttProperties mp : mps) {                log.info("==========Mqtt启动初始化配置:{}==========", JSON.toJSONString(mp));                //MqttClient mqttClient = MqttUtil.createMqttClient2(mp.getBrokers(), mp.getUserName(), mp.getPassword(), mp.getClientId());                MqttClient mqttClient = (MqttClient) applicationContext.getBean(mp.getClientId());                MqttConnectOptions mqttConnectOption = (MqttConnectOptions) applicationContext.getBean(MqttClientRegistrar.MQTT_OPS_PREFIX + mp.getClientId());                try {                    mqttClient.connect(mqttConnectOption);                } catch (MqttException e) {                    log.error("Mqtt启动连接异常ex:{}", e.getMessage());                }                if ("subscribe".equals(mp.getType())) {                    //MqttUtil.subscribe(mqttClient, mp.getTopic(), mp.getQos());                    try {                        mqttClient.subscribe(mp.getTopic(), mp.getQos());                    } catch (MqttException e) {                        log.error("Mqtt启动订阅异常ex:{}", e.getMessage());                    }                    log.info("==========Mqtt启动初始化订阅配置完成==========");                }                mqttClient.setCallback(new MqttCallback() {
                    public void connectionLost(Throwable cause) {                        log.error("connectionLost:{}", cause.getMessage());                    }
                    public void messageArrived(String topic, MqttMessage message) {                        String msg = new String(message.getPayload());                        int qos1 = message.getQos();                        log.info("subscribe topic:{}", topic);                        log.info("subscribe Qos:{}", qos1);                        log.info("subscribe msg:{}", msg);                        //新增业务拓展接口对接或者是发springEvent,业务监听该消息处理业务即可,这里采用事件监听的方式                        applicationContext.publishEvent(new MessageArrivedEvent(this, topic, message));                    }
                    public void deliveryComplete(IMqttDeliveryToken token) {                        log.info("delivery complete:{}", token.isComplete());                    }
                });            }        }        log.info("==========Mqtt启动初始化结束===========");    }
}
MqttApiService类如下，该类提供一套简易的在spring容器下使用的mqtt的api
package com.zlf.starter;
import com.zlf.config.MqttConfig;import com.zlf.config.MqttProperties;import com.zlf.util.MqttSpringUtils;import lombok.extern.slf4j.Slf4j;import org.apache.commons.collections4.CollectionUtils;import org.apache.commons.lang3.StringUtils;import org.eclipse.paho.client.mqttv3.IMqttMessageListener;import org.eclipse.paho.client.mqttv3.MqttCallback;import org.eclipse.paho.client.mqttv3.MqttClient;import org.eclipse.paho.client.mqttv3.MqttMessage;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;
import java.util.List;import java.util.Objects;
/** * @author zlf */@Service@Slf4jpublic class MqttApiService {
    @Autowired    private MqttConfig mqttConfig;
    @Autowired    private MqttSpringUtils mqttSpringUtils;
    public MqttProperties getMqttProperties(String clientId) {        List mps = mqttConfig.getMps();        if (CollectionUtils.isNotEmpty(mps)) {            for (MqttProperties mp : mps) {                if (mp.getClientId().equals(clientId)) {                    return mp;                }            }        }        return null;    }
    public MqttClient getMqttClient(String clientId) {        MqttClient mqttClient = (MqttClient) mqttSpringUtils.getBean(clientId);        return mqttClient;    }
    public MqttMessage createMessage(String topic, Integer qos, String content) {        // 创建消息并设置 QoS        MqttMessage message = new MqttMessage(content.getBytes());        if (Objects.isNull(qos)) {            //默认是1            qos = 1;            message.setQos(qos);        } else {            message.setQos(qos);        }        return message;    }
    public void publish0(MqttClient client, String topic, MqttMessage message) {        if (Objects.isNull(client)) {            throw new RuntimeException("MqttApiService publish client must not be null");        }        if (StringUtils.isBlank(topic)) {            throw new RuntimeException("MqttApiService publish topic must");        }        if (Objects.isNull(message)) {            throw new RuntimeException("MqttApiServicemessage must not be null");        }        if (message.getPayload().length == 0) {            throw new RuntimeException("MqttApiServicepublic message is empty");        }        try {            client.publish(topic, message);            //这里不用关闭这个客户端和连接            // 关闭连接            //client.disconnect();            // 关闭客户端            //client.close();        } catch (Exception e) {            log.error("MqttApiService publish error:{}", e.getMessage());        }    }

    public void subscribe0(MqttClient client, String topic, Integer qos, MqttCallback mqttCallback) {        if (Objects.isNull(client)) {            throw new RuntimeException("MqttApiService publish client is null");        }        if (StringUtils.isBlank(topic)) {            throw new RuntimeException("MqttApiService publish topic is empty");        }        if (Objects.isNull(qos)) {            qos = 1;        }        try {            // 设置回调            client.setCallback(mqttCallback);            client.subscribe(topic, qos);        } catch (Exception e) {            log.error("MqttApiService subscribe0 error:{}", e.getMessage());        }    }
    /**     * 发布     *     * @param clientId     * @param content     */    public void publish(String clientId, String content) {        if (StringUtils.isBlank(clientId)) {            throw new RuntimeException("MqttApiService publish clientId is empty");        }        if (StringUtils.isBlank(content)) {            throw new RuntimeException("MqttApiService publish content is empty");        }        MqttClient mqttClient = this.getMqttClient(clientId);        MqttProperties mqttProperties = this.getMqttProperties(clientId);        MqttMessage message = this.createMessage(mqttProperties.getTopic(), mqttProperties.getQos(), content);        this.publish0(mqttClient, mqttProperties.getTopic(), message);    }

    public void subscribe(String clientId, MqttCallback mqttCallback) {        if (StringUtils.isBlank(clientId)) {            throw new RuntimeException("MqttApiService subscribe clientId is empty");        }        MqttClient mqttClient = this.getMqttClient(clientId);        MqttProperties mqttProperties = this.getMqttProperties(clientId);        this.subscribe0(mqttClient, mqttProperties.getTopic(), mqttProperties.getQos(), mqttCallback);    }
    public void subscribe2(String clientId, IMqttMessageListener messageListener) {        if (StringUtils.isBlank(clientId)) {            throw new RuntimeException("MqttApiService subscribe2 clientId is empty");        }        MqttClient mqttClient = this.getMqttClient(clientId);        MqttProperties mqttProperties = this.getMqttProperties(clientId);        try {            mqttClient.subscribe(mqttProperties.getTopic(), mqttProperties.getQos(), messageListener);        } catch (Exception e) {            log.error("MqttApiService ubscribe2 error:{}", e.getMessage());        }    }
    public void unsubscribe(String clientId) {        if (StringUtils.isBlank(clientId)) {            throw new RuntimeException("MqttApiService unsubscribe clientId is empty");        }        MqttClient mqttClient = this.getMqttClient(clientId);        MqttProperties mqttProperties = this.getMqttProperties(clientId);        try {            mqttClient.unsubscribe(mqttProperties.getTopic());        } catch (Exception e) {            log.error("MqttApiService unsubscribe error:{}", e.getMessage());        }    }}
MqttController类如下，项目中引入上面的依赖和配置好上面的配置即可使用：
package xxx.controller;
import com.zlf.starter.MqttApiService;import lombok.extern.slf4j.Slf4j;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.RestController;
@Slf4j@RestController@RequestMapping("mqtt")public class MqttController {
    @Autowired    private MqttApiService mqttApiService;
    @GetMapping("/pubMsg")    public String pubMsg(@RequestParam(value = "msg") String msg) {        //String broker = "tcp://192.168.40.47:1883";        //String username = "zlf1";        //String password = "xxxx1明文";        String clientId = "zlf1_publish";        //String topic = "mqtt/test";        mqttApiService.publish(clientId, msg);        return "ok";    }
}


4.4测试验证

调用接口后订阅了mqtt/test主题的客户端可以收到消息：

跟使用工具类是一样的结果，其它EMQX后台的截图就不截图了，跟工具类是一样的截图，所以省略：


5.总结

mqtt使用场景大多是物联网方向，具体可以去百度一下，这里重点说下这个利用EMQX这个大规模开源分布式的消息服务器可以用来干嘛，比如可以用来做聊天、客户端和服务端的消息推送，其主要的思想就是发布-订阅模式。
多客户端如何创建用户名密码和clientId的思路，该集成适合服务端集成使用，在多Android、IOS客户端的下需要集成其它编程的SDK，后端服务只要根据业务为不同的用户终端生成EMQX的客户端相关信息，账号、密码，客户端id,以及订阅的Topic和Qos消息等级，然后业务根据用户信息生成了这些信息，然后将这个用户分配的MQX的客户端相关信息关联信息入库，MQX的客户端相关信息根据官方文档要求加密存入对应的redis中或者mysql中（只要按照官方那个规则将MQX的客户端相关信息入库即可），这个也比较简单，可以参考官方文档，提前编写代码实现即可，通过本文的分享，可以简单优雅的集成Mqtt，只需要引入一个依赖，在项目中配置一下即可，希望我的分享对你有所帮助，请一键三连，么么么哒！

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