一分钟在SpringBoot项目中使用EMQ

先展示最终的结果:

生产者端:

@RestController
@RequiredArgsConstructor
public class TestController {private final MqttProducer mqttProducer;@GetMapping("/test")public String test() {User build = User.builder().age(100).sex(1).address("世界潍坊渤海之眼").build();// 延时发布mqttProducer.send("$delayed/10/cookie", 2, JSON.toJSONString(build));return "ok";}}

消费者端

/*** @author : Cookie* date : 2024/1/30*/
@Component
@Topic("cookie")
public class TestTopicHandler implements MsgHandler {@Overridepublic void process(String jsonMsg) {User user = JSON.parseObject(jsonMsg, User.class);System.out.println(user);}}

控制台结果:

具体解释在之前的笔记中, 需要的话可以查看 EMQ的介绍及整合SpringBoot的使用-CSDN博客

---

OK, 下面我们就开始实现上面的逻辑, 你要做的就是把 1-9 复制到项目即可

1. 依赖导入

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

2. yml 配置

# 顶格
mqtt:client:username: adminpassword: publicserverURI: tcp://192.168.200.128:1883clientId: monitor.task.${random.int[10000,99999]} # 注意: emq的客户端id 不能重复keepAliveInterval: 10  #连接保持检查周期  秒connectionTimeout: 30 #连接超时时间  秒producer:defaultQos: 2defaultRetained: falsedefaultTopic: topic/test1consumer:consumerTopics: $queue/cookie/#, $share/group1/yfs1024  #不带群组的共享订阅    多个主题逗号隔开# $queue/cookie/## 以$queue开头，不带群组的共享订阅   多个客户端只能有一个消费者消费# $share/group1/yfs1024# 以$share开头，群组的共享订阅 多个客户端订阅# 如果在一个组 只能有一个消费者消费# 如果不在一个组 都可以消费

3. 属性配置

@Data
@Configuration
@ConfigurationProperties(prefix = "mqtt.client")
public class MqttConfigProperties {private int defaultProducerQos;private boolean defaultRetained;private String defaultTopic;private String username;private String password;private String serverURI;private String clientId;private int keepAliveInterval;private int connectionTimeout;}

4. 定义主题注解

@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
public @interface Topic {String value();
}

5.Mqtt配置类

@Data
@Slf4j
@Configuration
@RequiredArgsConstructor
public class MqttConfig {private final MqttConfigProperties configProperties;private final MqttCallback mqttCallback;@Beanpublic MqttClient mqttClient() {try {MqttClient client = new MqttClient(configProperties.getServerURI(), configProperties.getClientId(), mqttClientPersistence());client.setManualAcks(true); //设置手动消息接收确认mqttCallback.setMqttClient(client);client.setCallback(mqttCallback);client.connect(mqttConnectOptions());return client;} catch (MqttException e) {log.error("emq connect error", e);return null;}}@Beanpublic MqttConnectOptions mqttConnectOptions() {MqttConnectOptions options = new MqttConnectOptions();options.setUserName(configProperties.getUsername());options.setPassword(configProperties.getPassword().toCharArray());options.setAutomaticReconnect(true);//是否自动重新连接options.setCleanSession(true);//是否清除之前的连接信息options.setConnectionTimeout(configProperties.getConnectionTimeout());//连接超时时间options.setKeepAliveInterval(configProperties.getKeepAliveInterval());//心跳options.setMqttVersion(MqttConnectOptions.MQTT_VERSION_3_1_1);//设置mqtt版本return options;}public MqttClientPersistence mqttClientPersistence() {return new MemoryPersistence();}}

6. 定义消息处理接口

/*** 消息处理接口*/
public interface MsgHandler {void process(String jsonMsg) throws IOException;}

7.定义消息上下文

/*** 消息处理上下文, 通过主题拿到topic*/
public interface MsgHandlerContext{MsgHandler getMsgHandler(String topic);}

8. 定义回调类

@Component
@Slf4j
public class MqttCallback implements MqttCallbackExtended {// 需要订阅的topic配置@Value("${mqtt.consumer.consumerTopics}")private List<String> consumerTopics;@Autowiredprivate MsgHandlerContext msgHandlerContext;@Overridepublic void connectionLost(Throwable throwable) {log.error("emq error.", throwable);}@Overridepublic void messageArrived(String topic, MqttMessage message) throws Exception {log.info("topic:" + topic + "  message:" + new String(message.getPayload()));//处理消息String msgContent = new String(message.getPayload());log.info("接收到消息:" + msgContent);try {// 根据主题名称 获取 该主题对应的处理器对象// 多态 父类的引用指向子类的对象MsgHandler msgHandler = msgHandlerContext.getMsgHandler(topic);if (msgHandler == null) {return;}msgHandler.process(msgContent); //执行} catch (IOException e) {log.error("process msg error,msg is: " + msgContent, e);}//处理成功后确认消息mqttClient.messageArrivedComplete(message.getId(), message.getQos());}@Overridepublic void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {log.info("deliveryComplete---------" + iMqttDeliveryToken.isComplete());}@Overridepublic void connectComplete(boolean b, String s) {log.info("连接成功");//和EMQ连接成功后根据配置自动订阅topicif (consumerTopics != null && consumerTopics.size() > 0) {// 循环遍历当前项目中配置的所有的主题.consumerTopics.forEach(t -> {try {log.info(">>>>>>>>>>>>>>subscribe topic:" + t);// 订阅当前集群中所有的主题 消息服务质量 2 -> 至少收到一个mqttClient.subscribe(t, 2);} catch (MqttException e) {log.error("emq connect error", e);}});}}private MqttClient mqttClient;// 在配置类中调用传入连接public void setMqttClient(MqttClient mqttClient) {this.mqttClient = mqttClient;}
}

8. 消息处理类加载器

作用: 将Topic跟处理类对应 通过 handlerMap

/*** 消息处理类加载器* 作用:* 1. 因为实现了Spring 的 ApplicationContextAware 接口, 项目启动后就会运行实现的方法* 2. 获取MsgHandler接口的所有的实现类* 3. 将实现类上的Topic注解的值,作为handlerMap的键,实现类(处理器)作为对应的值*/
@Component
public class MsgHandlerContextImp implements ApplicationContextAware, MsgHandlerContext {private final Map<String, MsgHandler> handlerMap = new HashMap<>();@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {// 从spring容器中获取 <所有> 实现了MsgHandler接口的对象// key 默认类名首字母小写 value 当前对象Map<String, MsgHandler> map = applicationContext.getBeansOfType(MsgHandler.class);map.values().forEach(obj -> {// 通过反射拿到注解中的值  即 当前类处理的 topicString topic =  obj.getClass().getAnnotation(Topic.class).value();// 将主题和当前主题的处理类建立映射handlerMap.put(topic,obj);});}@Overridepublic MsgHandler getMsgHandler(String topic) {return handlerMap.get(topic);}
}

9. 封装消息生产者

@Slf4j
@Component
public class MqttProducer {// @Value() 读取配置 当然也可以批量读取配置,这里就一个一个了@Value("${mqtt.producer.defaultQos}")private int defaultProducerQos;@Value("${mqtt.producer.defaultRetained}")private boolean defaultRetained;@Value("${mqtt.producer.defaultTopic}")private String defaultTopic;@Autowiredprivate MqttClient mqttClient;public void send(String payload) {this.send(defaultTopic, payload);}public void send(String topic, String payload) {this.send(topic, defaultProducerQos, payload);}public void send(String topic, int qos, String payload) {this.send(topic, qos, defaultRetained, payload);}public void send(String topic, int qos, boolean retained, String payload) {try {mqttClient.publish(topic, payload.getBytes(), qos, retained);} catch (MqttException e) {log.error("publish msg error.",e);}}public <T> void send(String topic, int qos, T msg) throws JsonProcessingException {String payload = JsonUtil.serialize(msg);this.send(topic,qos,payload);}
}

最终的实现的结果

• 生产者端: 在需要发送消息的地方注入 MqttProducer 发送消息
• 消费者端: 在需要处理对应主题的类上 实现 MsgHandler接口

代码示例

生产者端

@RestController
@RequiredArgsConstructor
public class TestController {private final MqttProducer mqttProducer;@GetMapping("/test")public String test() {User build = User.builder().age(100).sex(1).address("世界潍坊渤海之眼").build();// 延时发布mqttProducer.send("$delayed/10/cookie", 2, JSON.toJSONString(build));return "ok";}
}

消费者端

@Component
@Topic("cookie")
public class TestTopicHandler implements MsgHandler {@Overridepublic void process(String jsonMsg) {User user = JSON.parseObject(jsonMsg, User.class);System.out.println(user);}}

控制台结果展示:

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补充JsonUtil

public class JsonUtil {/*** 从json字符串中根据nodeName获取值* @param nodeName* @param json* @return* @throws IOException*/public static String getValueByNodeName(String nodeName, String json) throws IOException {ObjectMapper objectMapper = new ObjectMapper();JsonNode jsonNode = objectMapper.readTree(json);JsonNode node = jsonNode.findPath(nodeName);if(node == null) return null;return node.asText();}/*** 根据nodeName获取节点内容* @param nodeName* @param json* @return* @throws IOException*/public static JsonNode getNodeByName(String nodeName, String json) throws IOException {ObjectMapper objectMapper = new ObjectMapper();return objectMapper.readTree(json).findPath(nodeName);}/*** 反序列化* @param json* @param clazz* @param <T>* @return* @throws IOException*/public static <T> T getByJson(String json, Class<T> clazz) throws IOException {ObjectMapper mapper = new ObjectMapper();// 在反序列化时忽略在 json 中存在但 Java 对象不存在的属性mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);// 在序列化时日期格式默认为 yyyy-MM-dd'T'HH:mm:ss.SSSZmapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);return mapper.readValue(json, clazz);}/*** 反序列化（驼峰转换）* @param json* @param clazz* @param <T>* @return* @throws IOException*/public static <T> T getByJsonSNAKE(String json, Class<T> clazz) throws IOException {ObjectMapper mapper = new ObjectMapper();// 在反序列化时忽略在 json 中存在但 Java 对象不存在的属性mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);// 在序列化时日期格式默认为 yyyy-MM-dd'T'HH:mm:ss.SSSZmapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);// 设置驼峰和下划线之间的映射mapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);return mapper.readValue(json, clazz);}/*** 序列化* @param object* @return* @throws JsonProcessingException*/public static String serialize(Object object) throws JsonProcessingException {ObjectMapper mapper = new ObjectMapper();return mapper.writeValueAsString(object);}/*** 序列化（驼峰转换）* @param object* @return* @throws JsonProcessingException*/public static String serializeSNAKE(Object object) throws JsonProcessingException {ObjectMapper mapper = new ObjectMapper();// 设置驼峰和下划线之间的映射mapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);return mapper.writeValueAsString(object);}public static JsonNode getTreeNode(String json) throws JsonProcessingException {ObjectMapper objectMapper = new ObjectMapper();return objectMapper.readTree(json);}/*** 将对象转map* @param obj* @return* @throws IOException*/public static Map<String,Object> convertToMap(Object obj) throws IOException {ObjectMapper mapper = new ObjectMapper();return mapper.readValue(serialize(obj),Map.class);}
}