浅谈MQTT监听设备上线与离线方法

package com.mqtt.demo.controller; import com.alibaba.fastjson.JSONObject; import com.mqtt.demo.config.MessagePublish; import com.mqtt.demo.config.MqttConfig; import com.mqtt.demo.entity.QosEnum; 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.persist.MemoryPersistence; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; import javax.annotation.PostConstruct; import java.util.HashMap; import java.util.Map; import java.util.UUID; @Component public class OnOffLineController { @Autowired private MqttConfig mqttConfig; private Logger logger = LoggerFactory.getLogger(OnOffLineController.class); @PostConstruct public void getOnOfflineDevice(){ String uuid = UUID.randomUUID().toString(); MemoryPersistence persistence = new MemoryPersistence(); MqttClient mqttClient = null; try { mqttClient = new MqttClient(mqttConfig.getBroker(), uuid,persistence); } catch (MqttException e) { logger.info("mqtt连接失败!!!"); e.printStackTrace(); } MqttConnectOptions options = new MqttConnectOptions(); options.setUserName(mqttConfig.getUserName()); options.setPassword(mqttConfig.getPassword().toCharArray()); Map<String,String> res = new HashMap<>(); res.put("clientId",uuid); res.put("status","disconnected"); String resJson = JSONObject.toJSONString(res); //立遗嘱，mqtt断开的时候向该主题发送消息 options.setWill("mqtt.onOffLine.status",resJson.getBytes(),2,false); options.setKeepAliveInterval(2000); options.setCleanSession(true); try { mqttClient.connect(options); Map<String,String> connectRes = new HashMap<>(); connectRes.put("clientId",uuid); connectRes.put("status","connected"); MessagePublish messagePublish = new MessagePublish(mqttClient); messagePublish.isPublish( "mqtt.onOffLine.status", JSONObject.toJSONString(connectRes), QosEnum.QOS2.getType()); } catch (MqttException e) { e.printStackTrace(); } } }