正文
MQTT 发布者订阅者
小程序：扫一扫查出行【扫一扫了解最新限行尾号】
复制小程序
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()));
}
}
