# 测试程序
【pom.xml】
<dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId><version>2.3.12.RELEASE</version></dependency><dependency><groupId>org.eclipse.paho</groupId><artifactId>org.eclipse.paho.mqttv5.client</artifactId><version>1.2.5</version></dependency><dependency><groupId>com.alibaba.fastjson2</groupId><artifactId>fastjson2</artifactId><version>2.0.49</version></dependency><dependency><groupId>ch.qos.logback</groupId><artifactId>logback-classic</artifactId><version>1.2.11</version></dependency>
</dependencies>
【MyDemo3MqttV5Server1.java】模拟一个正常的消息接收服务
package com.chz.myMqttV5.demo3;import lombok.extern.slf4j.Slf4j;
import org.eclipse.paho.mqttv5.client.*;
import org.eclipse.paho.mqttv5.common.MqttException;
import org.eclipse.paho.mqttv5.common.MqttMessage;
import org.eclipse.paho.mqttv5.common.packet.MqttProperties;import java.util.concurrent.ThreadLocalRandom;@Slf4j
public class MyDemo3MqttV5Server1
{public static void main(String[] args) throws InterruptedException{String broker = "tcp://192.168.44.228:1883";String clientId = "MyDemo3MqttV5Server1";int subQos = 1;try {MqttClient client = new MqttClient(broker, clientId);MqttConnectionOptions options = new MqttConnectionOptions();options.setAutomaticReconnect(true);client.setCallback(new MyDemo3Server1Callback(clientId));client.connect(options);client.subscribe("$share/demo3/device/#", subQos);} catch (MqttException e) {e.printStackTrace();}}@Slf4jpublic static class MyDemo3Server1Callback implements MqttCallback{private String clientId;public MyDemo3Server1Callback(String clientId){this.clientId = clientId;}public void connectComplete(boolean reconnect, String serverURI) {log.info("{}::connectComplete, reconnect={}, serverURI={}", clientId, reconnect, serverURI);}public void disconnected(MqttDisconnectResponse disconnectResponse) {log.info("{}::disconnected, disconnectResponse={}", clientId, disconnectResponse.getReasonString());}public void deliveryComplete(IMqttToken token) {log.info("{}::deliveryComplete, disconnectResponse={}", clientId, token.isComplete());}public void messageArrived(String topic, MqttMessage message) throws Exception {log.info("{}::messageArrived, topic={}, qos={}, message={}", clientId, topic, message.getQos(), new String(message.getPayload()));}public void mqttErrorOccurred(MqttException exception) {log.info("{}::mqttErrorOccurred, disconnectResponse={}", clientId, exception.getMessage());}public void authPacketArrived(int reasonCode, MqttProperties properties) {log.info("{}::authPacketArrived, reasonCode={}", clientId, reasonCode);}}
}
【MyDemo3MqttV5Server2.java】模拟一个工作不正常的消息接收不服务
package com.chz.myMqttV5.demo3;import lombok.extern.slf4j.Slf4j;
import org.eclipse.paho.mqttv5.client.*;
import org.eclipse.paho.mqttv5.common.MqttException;
import org.eclipse.paho.mqttv5.common.MqttMessage;
import org.eclipse.paho.mqttv5.common.packet.MqttProperties;import java.util.concurrent.ThreadLocalRandom;@Slf4j
public class MyDemo3MqttV5Server2
{private static int subQos = 1;public static void main(String[] args) throws InterruptedException{String broker = "tcp://192.168.44.228:1883";String clientId = "MyDemo3MqttV5Server2";try {MqttClient client = new MqttClient(broker, clientId);MqttConnectionOptions options = new MqttConnectionOptions();options.setAutomaticReconnect(true);options.setKeepAliveInterval(3); // keepAliveInterval设置成3秒client.setCallback(new MyDemo3Server2Callback(clientId, client));client.connect(options);} catch (MqttException e) {e.printStackTrace();}}@Slf4jpublic static class MyDemo3Server2Callback implements MqttCallback{private String clientId;private MqttClient client;public MyDemo3Server2Callback(String clientId, MqttClient client){this.clientId = clientId;this.client = client;}public void connectComplete(boolean reconnect, String serverURI) {log.info("{}::connectComplete, reconnect={}, serverURI={}", clientId, reconnect, serverURI);try {if( client.isConnected() ){client.subscribe("$share/demo3/device/#", subQos);}} catch (MqttException e) {log.error("err", e);}}public void disconnected(MqttDisconnectResponse disconnectResponse) {log.info("{}::disconnected, disconnectResponse={}", clientId, disconnectResponse.getReasonString());}public void deliveryComplete(IMqttToken token) {log.info("{}::deliveryComplete, disconnectResponse={}", clientId, token.isComplete());}public void messageArrived(String topic, MqttMessage message) throws Exception {log.info("{}::messageArrived start, topic={}, qos={}, message={}", clientId, topic, message.getQos(), new String(message.getPayload()));if( ThreadLocalRandom.current().nextInt() % 20 ==0 ){try {log.info("{}::messageArrived ------------error1, topic={}, qos={}, message={}", clientId, topic, message.getQos(), new String(message.getPayload()));// 休眠10秒,因为前面设置了keepAliveInterval为3秒,所以一定会导致连接断开Thread.sleep(10000);log.info("{}::messageArrived ------------error2, topic={}, qos={}, message={}", clientId, topic, message.getQos(), new String(message.getPayload()));} catch (Exception e) {log.error("err", e);}}}public void mqttErrorOccurred(MqttException exception) {log.info("{}::mqttErrorOccurred, disconnectResponse={}", clientId, exception.getMessage());}public void authPacketArrived(int reasonCode, MqttProperties properties) {log.info("{}::authPacketArrived, reasonCode={}", clientId, reasonCode);}}
}
【MyDemo3MqttV5Sender.java】模拟一个发消息出来的设备
package com.chz.myMqttV5.demo3;import lombok.extern.slf4j.Slf4j;
import org.eclipse.paho.mqttv5.client.*;
import org.eclipse.paho.mqttv5.common.MqttException;
import org.eclipse.paho.mqttv5.common.MqttMessage;
import org.eclipse.paho.mqttv5.common.packet.MqttProperties;@Slf4j
public class MyDemo3MqttV5Sender {private static String clientId = MyDemo3MqttV5Sender.class.getSimpleName();public static void main(String[] args) throws InterruptedException {String broker = "tcp://192.168.44.228:1883";int subQos = 1;int pubQos = 1;String msg;try {MqttClient client = new MqttClient(broker, clientId);MqttConnectionOptions options = new MqttConnectionOptions();client.setCallback(new MyDemo3SenderCallback(clientId));client.connect(options);client.subscribe("device/#", subQos);for(int i=0; i<200; i++){int id = i;msg = id+"";MqttMessage message = new MqttMessage(msg.getBytes());message.setId(id); // 这个id很重要,否则qos=1不会生效message.setQos(pubQos); // 设置qos=1client.publish("device/1", message);Thread.sleep(1L);}} catch (MqttException e) {e.printStackTrace();}}@Slf4jpublic static class MyDemo3SenderCallback implements MqttCallback{private String clientId;public MyDemo3SenderCallback(String clientId){this.clientId = clientId;}public void connectComplete(boolean reconnect, String serverURI) {log.info("{}::MyMqttCallback, reconnect={}, serverURI={}", clientId, reconnect, serverURI);}public void disconnected(MqttDisconnectResponse disconnectResponse) {log.info("{}::disconnected, disconnectResponse={}", clientId, disconnectResponse.getReasonString());}public void deliveryComplete(IMqttToken token) {log.info("{}::deliveryComplete, disconnectResponse={}", clientId, token.isComplete());}public void messageArrived(String topic, MqttMessage message) throws Exception {log.info("{}::messageArrived, topic={}, qos={}, message={}", clientId, topic, message.getQos(), new String(message.getPayload()));}public void mqttErrorOccurred(MqttException exception) {log.info("{}::mqttErrorOccurred, disconnectResponse={}", clientId, exception.getMessage());}public void authPacketArrived(int reasonCode, MqttProperties properties) {log.info("{}::authPacketArrived, reasonCode={}", clientId, reasonCode);}}
}
# 开始测试
启动【MyDemo3MqttV5Server1、MyDemo3MqttV5Server2】
然后启动【MyDemo3MqttV5Sender】,输出日志如下:
可以看到【MyDemo3MqttV5Server2】接收到消息【74】的时候卡了10秒,然后连接就断开了。
可以看到【MyDemo3MqttV5Server2】断开连接之后,消息【74】之后的后续消息都被【MyDemo3MqttV5Server1】接收到了。换句话说不会因为某个消息接收服务的问题导致消息丢失。
# 参考资料
mqtt服务emqx的安装可以参考https://blog.csdn.net/chenhz2284/article/details/139411874