ActiveMQ笔记(7)：如何清理无效的延时消息？

ActiveMQ的延时消息是一个让人又爱又恨的功能，具体使用可参考上篇ActiveMQ笔记(6)：消息延时投递，在很多需要消息延时投递的业务场景十分有用，但是也有一个缺陷，在一些大访问量的场景，如果瞬间向MQ发送海量的延时消息，超过MQ的调度能力，就会造成很多消息到了该投递的时刻，却没有投递出去，形成积压，一直停留在ActiveMQ web控制台的Scheduled面板中。

下面的代码演示了，如何清理activemq中的延时消息（包括：全部清空及清空指定时间段的延时消息），这也是目前唯一可行的办法。

为了演示方便，先封装一个小工具类：

package cn.mwee.utils.mq;

import cn.mwee.utils.list.ListUtil;
import cn.mwee.utils.log4j2.MwLogger;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.springframework.jms.core.JmsTemplate;
import org.springframework.jms.core.MessagePostProcessor;

import javax.jms.ConnectionFactory;
import javax.jms.JMSException;
import javax.jms.TextMessage;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

/**
 * Created by yangjunming on 6/20/16.
 */
public final class MessageUtil {

    private Logger logger = new MwLogger(MessageUtil.class);//这里就是一个Log4j2的实例,大家可以换成原生的log4j2或类似工具

    private ConnectionFactory connectionFactory;
    private long receiveTimeout;//接收超时时间
    private JmsTemplate jmsTemplate;
    private List<String> destinationQueueNames;
    private final static String BACKUP_QUEUE_SUFFIX = "_B";
    private boolean autoBackup = false;//是否自动将消息备份到_b的队列，方便调试

    public MessageUtil(final ConnectionFactory connectionFactory, final long receiveTimeout, final List<String> destinationQueueNames) {
        this.connectionFactory = connectionFactory;
        this.receiveTimeout = receiveTimeout;
        this.destinationQueueNames = new ArrayList<>();
        this.destinationQueueNames.addAll(destinationQueueNames.stream().collect(Collectors.toList()));
        jmsTemplate = new JmsTemplate(this.connectionFactory);
        jmsTemplate.setReceiveTimeout(this.receiveTimeout);
    }

    public MessageUtil(ConnectionFactory connectionFactory, List<String> destinationQueueNames) {
        this(connectionFactory, 10000, destinationQueueNames);
    }

    public void convertAndSend(Object message) {
        if (ListUtil.isEmpty(destinationQueueNames)) {
            logger.error("目标队列为空，无法发送，请检查配置！message => " + message.toString());
            return;
        }
        for (String dest : destinationQueueNames) {
            jmsTemplate.convertAndSend(dest, message);
            if (autoBackup) {
                jmsTemplate.convertAndSend(dest + BACKUP_QUEUE_SUFFIX, message);
            }
        }
    }

    public void convertAndSend(Object message, MessagePostProcessor messagePostProcessor) {
        if (ListUtil.isEmpty(destinationQueueNames)) {
            logger.error("目标队列为空，无法发送，请检查配置！message => " + message.toString());
            return;
        }
        for (String dest : destinationQueueNames) {
            jmsTemplate.convertAndSend(dest, message, messagePostProcessor);
            if (autoBackup) {
                jmsTemplate.convertAndSend(dest + BACKUP_QUEUE_SUFFIX, message, messagePostProcessor);
            }
        }
    }

    public void convertAndSend(String destinationName, Object message) {
        if (StringUtils.isBlank(destinationName)) {
            logger.error("目标队列为空，无法发送，请检查配置！message => " + message.toString());
            return;
        }
        jmsTemplate.convertAndSend(destinationName, message);
        if (autoBackup) {
            jmsTemplate.convertAndSend(destinationName + BACKUP_QUEUE_SUFFIX, message);
        }
    }

    public void convertAndSend(String destinationName, Object message, MessagePostProcessor messagePostProcessor) {
        if (StringUtils.isBlank(destinationName)) {
            logger.error("目标队列为空，无法发送，请检查配置！message => " + message.toString());
            return;
        }
        jmsTemplate.convertAndSend(destinationName, message, messagePostProcessor);
        if (autoBackup) {
            jmsTemplate.convertAndSend(destinationName + BACKUP_QUEUE_SUFFIX, message, messagePostProcessor);
        }
    }

    public static String getText(javax.jms.Message message) {
        if (message instanceof TextMessage) {
            try {
                return ((TextMessage) message).getText();
            } catch (JMSException e) {
                return message.toString();
            }
        }
        return message.toString();
    }

    public String getFirstDestination() {
        if (ListUtil.isEmpty(destinationQueueNames)) {
            return null;
        }
        return destinationQueueNames.get(0);
    }

    public boolean isAutoBackup() {
        return autoBackup;
    }

    public void setAutoBackup(boolean autoBackup) {
        this.autoBackup = autoBackup;
    }
}

其中主要就用到了convertAndSend(Object message, MessagePostProcessor messagePostProcessor) 这个方法，其它代码可以无视。

先来模拟瞬间向MQ发送大量延时消息：

    /**
     * 发送延时消息
     *
     * @param messageUtil
     */
    private static void sendScheduleMessage(MessageUtil messageUtil) {
        for (int i = 0; i < 10000; i++) {
            Object obj = "test:" + i;
            messageUtil.convertAndSend(obj, new ScheduleMessagePostProcessor(1000 + i * 1000));
        }
    }

这里向MQ发送了1w条延时消息，每条消息延时1秒*i，上面代码中的ScheduleMessagePostProcessor类可在上篇中找到。

运行完之后，MQ中应该堆积着了很多消息了：

下面的代码可以清空所有延时消息：

    /**
     * 删除所有延时消息
     *
     * @param connectionFactory
     * @throws JMSException
     */
    private static void deleteAllScheduleMessage(final ConnectionFactory connectionFactory) throws JMSException {
        Connection conn = connectionFactory.createConnection();
        Session session = conn.createSession(false, Session.AUTO_ACKNOWLEDGE);
        Destination management = session.createTopic(ScheduledMessage.AMQ_SCHEDULER_MANAGEMENT_DESTINATION);
        MessageProducer producer = session.createProducer(management);
        Message request = session.createMessage();
        request.setStringProperty(ScheduledMessage.AMQ_SCHEDULER_ACTION, ScheduledMessage.AMQ_SCHEDULER_ACTION_REMOVEALL);
        producer.send(request);
    }

清空所有延时消息，有些用力过猛了，很多时候，我们只需要清理掉过期的延时消息（即：本来计划是8:00投递出去的消息，结果过了8点还没投递出去）

    /**
     * 删除过期的延时消息
     *
     * @param connectionFactory
     * @throws JMSException
     */
    private static void deleteExpiredScheduleMessage(final ConnectionFactory connectionFactory) throws JMSException {
        long start = System.currentTimeMillis() - TimeUnit.HOURS.toMillis(12);//删除：当前时间前12小时范围的延时消息
        long end = System.currentTimeMillis();
        Connection conn = connectionFactory.createConnection();
        Session session = conn.createSession(false, Session.AUTO_ACKNOWLEDGE);
        Destination management = session.createTopic(ScheduledMessage.AMQ_SCHEDULER_MANAGEMENT_DESTINATION);
        MessageProducer producer = session.createProducer(management);
        Message request = session.createMessage();
        request.setStringProperty(ScheduledMessage.AMQ_SCHEDULER_ACTION, ScheduledMessage.AMQ_SCHEDULER_ACTION_REMOVEALL);
        request.setStringProperty(ScheduledMessage.AMQ_SCHEDULER_ACTION_START_TIME, Long.toString(start));
        request.setStringProperty(ScheduledMessage.AMQ_SCHEDULER_ACTION_END_TIME, Long.toString(end));
        producer.send(request);
    }

与上一段代码基本相似，只是多指定了删除消息的起止时间段。　　

最后贴一段spring的配置文件及main函数入口

 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

     <bean id="jmsFactory" class="org.apache.activemq.pool.PooledConnectionFactory" destroy-method="stop">
         <property name="connectionFactory">
             <bean class="org.apache.activemq.ActiveMQConnectionFactory">
                 <property name="brokerURL"
                           value="failover:(tcp://localhost:61616,tcp://localhost:61626)?randomize=false&amp;backup=true"/>
                 <property name="maxThreadPoolSize" value="100"/>
             </bean>
         </property>
     </bean>

     <bean id="messageUtil" class="cn.mwee.utils.mq.MessageUtil">
         <constructor-arg index="0" ref="jmsFactory"/>
         <constructor-arg index="1" value="10000"/>
         <constructor-arg index="2">
             <list>
                 <value>dest1</value>
                 <value>dest2</value>
             </list>
         </constructor-arg>
         <property name="autoBackup" value="true"/>
     </bean>

 </beans>

main函数：

    public static void main(String[] args) throws InterruptedException, JMSException {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring-sender.xml");
        ConnectionFactory connectionFactory = context.getBean(ConnectionFactory.class, "jmsFactory");
        MessageUtil messageUtil = context.getBean(MessageUtil.class);
//        sendScheduleMessage(messageUtil);
//        deleteAllScheduleMessage(connectionFactory);
        deleteExpiredScheduleMessage(connectionFactory);
    }

参考文章：

Enhanced JMS Scheduler in ActiveMQ