MQTT 发布者订阅者
添加依赖:
<dependency> <groupId>org.eclipse.paho</groupId> <artifactId>org.eclipse.paho.client.mqttv3</artifactId> <version>1.1.1</version> </dependency>
MQ发布者:
package com.ra.car.utils; import org.eclipse.paho.client.mqttv3.MqttClient; import org.eclipse.paho.client.mqttv3.MqttConnectOptions; import org.eclipse.paho.client.mqttv3.MqttDeliveryToken; import org.eclipse.paho.client.mqttv3.MqttException; import org.eclipse.paho.client.mqttv3.MqttMessage; import org.eclipse.paho.client.mqttv3.MqttPersistenceException; import org.eclipse.paho.client.mqttv3.MqttTopic; import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * MQ发布者 * * @author lanhao * */ public class MQTTPubMsg { protected static final Logger logger = LoggerFactory .getLogger(MQTTPubMsg.class); public static final String HOST = "tcp://10.74.20.43:1883"; public static final String TOPIC = "toclient/124"; // public static final String TOPIC125 = "toclient/125"; private static final String clientid = "server"; private MqttClient client; private MqttTopic topic; // private MqttTopic topic125; private String userName = "root"; private String passWord = "Passw0rd"; private MqttMessage message; public MQTTPubMsg() throws MqttException { // MemoryPersistence设置clientid的保存形式，默认为以内存保存 client = new MqttClient(HOST, clientid, new MemoryPersistence()); connect(); } private void connect() { MqttConnectOptions options = new MqttConnectOptions(); options.setCleanSession(false); options.setUserName(userName); options.setPassword(passWord.toCharArray()); // 设置超时时间 options.setConnectionTimeout(10); // 设置会话心跳时间 options.setKeepAliveInterval(20); try { client.setCallback(new MQTTPushCallback()); client.connect(options); topic = client.getTopic(TOPIC); // topic125 = client.getTopic(TOPIC125); } catch (Exception e) { logger.error("MQ发布者connect异常......",e); } } public void publish(MqttTopic topic, MqttMessage message) throws MqttPersistenceException, MqttException { MqttDeliveryToken token = topic.publish(message); token.waitForCompletion(); logger.info("message is published completely! " + token.isComplete()); } public static void main(String[] args) throws MqttException { MQTTPubMsg server = new MQTTPubMsg(); String s="这是第一条消息"; server.message = new MqttMessage(); server.message.setQos(2); server.message.setRetained(true); server.message.setPayload(s.getBytes()); server.publish(server.topic, server.message); try { Thread.sleep(20000); } catch (InterruptedException e) { } for (int i = 0; i < 500; i++) { String str = "这是后续循环发送的消息" + i; server.message = new MqttMessage(); server.message.setQos(2); server.message.setRetained(true); server.message.setPayload(str.getBytes()); server.publish(server.topic, server.message); // 给另外一个topic发送消息 * server.message = new MqttMessage(); server.message.setQos(2); * server.message.setRetained(true); * server.message.setPayload("给客户端125推送的信息".getBytes()); * server.publish(server.topic125, server.message); logger.info(server.message.isRetained() + "------ratained状态"); } } }
MQ订阅者:
package com.ra.car.utils; 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.MqttTopic; import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * MQ订阅者 * * @author lanhao * */ public class MQTTSubMsg { protected static final Logger logger = LoggerFactory .getLogger(MQTTSubMsg.class); public static final String HOST = "tcp://10.74.20.43:1883"; public static final String TOPIC = "toclient/124"; private static final String clientid = "client124"; private MqttClient client; private MqttConnectOptions options; private String userName = "root"; private String passWord = "Passw0rd"; public void start() { try { logger.info("SubMsg----->start"); // host为主机名，clientid即连接MQTT的客户端ID，一般以唯一标识符表示，MemoryPersistence设置clientid的保存形式，默认为以内存保存 client = new MqttClient(HOST, clientid, new MemoryPersistence()); // MQTT的连接设置 options = new MqttConnectOptions(); // 设置是否清空session,这里如果设置为false表示服务器会保留客户端的连接记录，这里设置为true表示每次连接到服务器都以新的身份连接 options.setCleanSession(true); // 设置连接的用户名 options.setUserName(userName); // 设置连接的密码 options.setPassword(passWord.toCharArray()); // 设置超时时间 单位为秒 options.setConnectionTimeout(10); // 设置会话心跳时间 单位为秒 服务器会每隔1.5*20秒的时间向客户端发送个消息判断客户端是否在线，但这个方法并没有重连的机制 options.setKeepAliveInterval(20); // 设置回调 client.setCallback(new MQTTPushCallback()); MqttTopic topic = client.getTopic(TOPIC); // setWill方法，如果项目中需要知道客户端是否掉线可以调用该方法。设置最终端口的通知消息 options.setWill(topic, "close".getBytes(), 2, true); client.connect(options); // 订阅消息 int[] Qos = { 2 }; String[] topic1 = { TOPIC }; client.subscribe(topic1, Qos); } catch (Exception e) { logger.error("MQ订阅者异常",e); } } public static void main(String[] args) throws MqttException { MQTTSubMsg client = new MQTTSubMsg(); client.start(); } }
回调类:
package com.ra.car.utils; import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken; import org.eclipse.paho.client.mqttv3.MqttCallback; import org.eclipse.paho.client.mqttv3.MqttMessage; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * 发布消息的回调类 * * 必须实现MqttCallback的接口并实现对应的相关接口方法CallBack 类将实现 MqttCallBack。 * 每个客户机标识都需要一个回调实例。在此示例中，构造函数传递客户机标识以另存为实例数据。 在回调中，将它用来标识已经启动了该回调的哪个实例。 * 必须在回调类中实现三个方法 */ public class MQTTPushCallback implements MqttCallback{ protected static final Logger logger = LoggerFactory .getLogger(MQTTPushCallback.class); public void connectionLost(Throwable cause) { // 在断开连接时调用,连接丢失后,一般在这里面进行重连. logger.info("连接断开，可以做重连"); } public void deliveryComplete(IMqttDeliveryToken token) { //接收到已经发布的 QoS 1 或 QoS 2 消息的传递令牌时调用. 由 MqttClient.connect 激活此回调. logger.info("deliveryComplete---------" + token.isComplete()); } public void messageArrived(String topic, MqttMessage message) throws Exception { // subscribe后得到的消息会执行到这里面 logger.info("接收消息主题 : " + topic); logger.info("接收消息Qos : " + message.getQos()); logger.info("接收消息内容 : " + new String(message.getPayload())); } }
