接上一节问题:
单使用@RefreshScope + @Value以上4种场景均不能生效(需要重启spring boot项目,mqtt服务器才能重新连接)
当我们修改nacos值时,发现控制台打印信息如下
查看 RefreshEventListener.class 代码,发现当naocs变化时handle方法会调用,并打印变化的key
public void handle(RefreshEvent event) {
if (this.ready.get()) {
log.debug("Event received " + event.getEventDesc());
Set keys = this.refresh.refresh();
log.info("Refresh keys changed: " + keys);
}
}
所以,只需要参考 RefreshEventListener.class 新建一个监听类 MqttConfigListener.java即可
说明:关键看
MqttConfigListener.java
package com.hzd.listener;
import com.hzd.mqtt.client.EmqClient;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.cloud.context.refresh.ContextRefresher;
import org.springframework.cloud.endpoint.event.RefreshEvent;
import org.springframework.cloud.endpoint.event.RefreshEventListener;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.event.SmartApplicationListener;
import org.springframework.stereotype.Component;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* Coding by 李炯 on 2022/11/11 11:24
*/
@Component
@Slf4j
public class MqttConfigListener implements SmartApplicationListener {
@Autowired
private EmqClient emqClient;
private ContextRefresher refresh;
private AtomicBoolean ready = new AtomicBoolean(false);
public MqttConfigListener(ContextRefresher refresh) {
this.refresh = refresh;
}
public boolean supportsEventType(Class eventType) {
return ApplicationReadyEvent.class.isAssignableFrom(eventType) || RefreshEvent.class.isAssignableFrom(eventType);
}
public void onApplicationEvent(ApplicationEvent event) {
if (event instanceof ApplicationReadyEvent) {
this.handle((ApplicationReadyEvent)event);
} else if (event instanceof RefreshEvent) {
this.handle((RefreshEvent)event);
}
}
public void handle(ApplicationReadyEvent event) {
this.ready.compareAndSet(false, true);
}
public void handle(RefreshEvent event) {
if (this.ready.get()) {
Set keys = this.refresh.refresh();
log.info("Refresh keys changed>>>>>>>>: " + keys.toString());
if (keys.toString().contains("mqtt")){
emqClient.disConnect();//断开之前的连接
emqClient.init();//重新连接EMQX
}
}
}
}
EmqClient.java
package com.hzd.mqtt.client;
import com.hzd.mqtt.enums.QosEnum;
import com.hzd.mqtt.properties.MqttProperties;
import lombok.extern.slf4j.Slf4j;
import org.eclipse.paho.client.mqttv3.*;
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.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Primary;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
/**
* Created by
*/
@Component
@Slf4j
public class EmqClient {
private IMqttClient mqttClient;
@Autowired
private MqttProperties mqttProperties;
@Autowired
private MqttCallback mqttCallback;
@Autowired
private MqttProperties properties;
@PostConstruct
public void init() {
MqttClientPersistence mempersitence = new MemoryPersistence();
try {
mqttClient = new MqttClient(mqttProperties.getBrokerUrl(), mqttProperties.getClientId(), mempersitence);
} catch (MqttException e) {
log.error("初始化客户端mqttClient对象失败,errormsg={},brokerUrl={},clientId={}", e.getMessage(), mqttProperties.getBrokerUrl(), mqttProperties.getClientId());
}
//连接服务端
connect(properties.getUsername(), properties.getPassword());
//订阅一个主题
String topic_hzd = "/hzd/pub/#";
String topic_device_connect = "/device/connect/#";
subscribe(topic_hzd, QosEnum.QoS2);
subscribe(topic_device_connect, QosEnum.QoS2);
log.info("EmqClient连接成功,订阅成功.topic={},{}", topic_hzd, topic_device_connect);
}
/**
* 连接broker
*
* @param username
* @param password
*/
public void connect(String username, String password) {
MqttConnectOptions options = new MqttConnectOptions();
options.setAutomaticReconnect(true);
options.setUserName(username);
options.setPassword(password.toCharArray());
options.setCleanSession(true);
mqttClient.setCallback(mqttCallback);
try {
mqttClient.connect(options);
} catch (MqttException e) {
log.error("mqtt客户端连接服务端失败,失败原因{}", e.getMessage());
}
}
/**
* 断开连接
*/
@PreDestroy
public void disConnect() {
try {
mqttClient.disconnect();
} catch (MqttException e) {
log.error("断开连接产生异常,异常信息{}", e.getMessage());
}
}
/**
* 重连
*/
public void reConnect() {
try {
mqttClient.reconnect();
} catch (MqttException e) {
log.error("重连失败,失败原因{}", e.getMessage());
}
}
/**
* 发布消息
*
* @param topic
* @param msg
* @param qos
* @param retain
*/
public void publish(String topic, String msg, QosEnum qos, boolean retain) {
MqttMessage mqttMessage = new MqttMessage();
mqttMessage.setPayload(msg.getBytes());
mqttMessage.setQos(qos.value());
mqttMessage.setRetained(retain);
try {
mqttClient.publish(topic, mqttMessage);
} catch (MqttException e) {
log.error("发布消息失败,errormsg={},topic={},msg={},qos={},retain={}", e.getMessage(), topic, msg, qos.value(), retain);
}
}
/**
* 订阅
*
* @param topicFilter
* @param qos
*/
public void subscribe(String topicFilter, QosEnum qos) {
try {
mqttClient.subscribe(topicFilter, qos.value());
} catch (MqttException e) {
log.error("订阅主题失败,errormsg={},topicFilter={},qos={}", e.getMessage(), topicFilter, qos.value());
}
}
/**
* 取消订阅
*
* @param topicFilter
*/
public void unSubscribe(String topicFilter) {
try {
mqttClient.unsubscribe(topicFilter);
} catch (MqttException e) {
log.error("取消订阅失败,errormsg={},topicfiler={}", e.getMessage(), topicFilter);
}
}
}