ActiveMQ故障切换似乎不起作用

Question

我有一个超级简单的场景：一个代理和一个持久订阅的消费者。这是我的消费者应用程序的代码：

package test;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;
import org.apache.activemq.ActiveMQConnectionFactory;
import pojo.Event;
import pojo.StockUpdate;
public class Consumer
{
    private static transient ConnectionFactory factory;
    private transient Connection connection;
    private transient Session session;
    public static int counter = 0;
    public Consumer(String brokerURL) throws JMSException
    {
        factory = new ActiveMQConnectionFactory(brokerURL);
        connection = factory.createConnection();
        connection.setClientID("CLUSTER_CLIENT_1");
        connection.start();
        session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
    }
    public void close() throws JMSException
    {
        if (connection != null)
        {
            connection.close();
        }
    }
    public static void main(String[] args) throws JMSException
    {
        try
        {
            // extract topics from the rest of arguments
            String[] topics = new String[2];
            topics[0] = "CSCO";
            topics[1] = "ORCL";
            // define connection URI
            Consumer consumer = new Consumer("failover:(tcp://localhost:61616)?maxReconnectAttempts=-1&useExponentialBackOff=true");
            for (String stock : topics)
            {
                try
                {
                    Destination destination = consumer.getSession().createTopic("STOCKS." + stock);
                    // consumer.getSession().
                    MessageConsumer messageConsumer = consumer.getSession().createDurableSubscriber((Topic) destination, "STOCKS_DURABLE_CONSUMER_" + stock);
                    messageConsumer.setMessageListener(new Listener());
                }
                catch (JMSException e)
                {
                    e.printStackTrace();
                }
            }
        }
        catch (Throwable t)
        {
            t.printStackTrace();
        }
    }
    public Session getSession()
    {
        return session;
    }
}
class Listener implements MessageListener
{
    public void onMessage(Message message)
    {
        try
        {
            TextMessage textMessage = (TextMessage) message;
            String json = textMessage.getText();
            Event event = StockUpdate.fromJSON(json, StockUpdate.class);
            System.out.println("Consumed message #:" + ++Consumer.counter + "n" + event);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}

这是我的activemq.xml

<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
  http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/activemq-core.xsd">
    <!-- Allows us to use system properties as variables in this configuration file -->
    <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <value>file:${activemq.conf}/credentials.properties</value>
        </property>
    </bean>
    <!--
        The <broker> element is used to configure the ActiveMQ broker.
    -->
    <broker xmlns="http://activemq.apache.org/schema/core" brokerName="R6_cluster_broker1" persistent="true">
        <networkConnectors>
            <networkConnector uri="static:(failover:(tcp://remote_master:61616,tcp://remote_slave:61617))"/>
        </networkConnectors>
        <destinationPolicy>
            <policyMap>
              <policyEntries>
                <policyEntry topic=">" >
                    <!-- The constantPendingMessageLimitStrategy is used to prevent
                         slow topic consumers to block producers and affect other consumers
                         by limiting the number of messages that are retained
                         For more information, see:
                         http://activemq.apache.org/slow-consumer-handling.html
                    -->
                  <pendingMessageLimitStrategy>
                    <constantPendingMessageLimitStrategy limit="1000"/>
                  </pendingMessageLimitStrategy>
                </policyEntry>
              </policyEntries>
            </policyMap>
        </destinationPolicy>

        <!--
            The managementContext is used to configure how ActiveMQ is exposed in
            JMX. By default, ActiveMQ uses the MBean server that is started by
            the JVM. For more information, see:
            http://activemq.apache.org/jmx.html
        -->
        <managementContext>
            <managementContext createConnector="false"/>
        </managementContext>
        <!--
            Configure message persistence for the broker. The default persistence
            mechanism is the KahaDB store (identified by the kahaDB tag).
            For more information, see:
            http://activemq.apache.org/persistence.html
        -->
        <persistenceAdapter>
            <kahaDB directory="/work/temp/kahadb"/>
        </persistenceAdapter>

          <!--
            The systemUsage controls the maximum amount of space the broker will
            use before disabling caching and/or slowing down producers. For more information, see:
            http://activemq.apache.org/producer-flow-control.html
          -->
          <systemUsage>
            <systemUsage>
                <memoryUsage>
                    <memoryUsage percentOfJvmHeap="70" />
                </memoryUsage>
                <storeUsage>
                    <storeUsage limit="100 gb"/>
                </storeUsage>
                <tempUsage>
                    <tempUsage limit="50 gb"/>
                </tempUsage>
            </systemUsage>
        </systemUsage>
        <!--
            The transport connectors expose ActiveMQ over a given protocol to
            clients and other brokers. For more information, see:
            http://activemq.apache.org/configuring-transports.html
        -->
        <transportConnectors>
            <!-- DOS protection, limit concurrent connections to 1000 and frame size to 100MB -->
            <transportConnector name="openwire" uri="tcp://0.0.0.0:61616?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
            <!-- <transportConnector name="amqp" uri="amqp://0.0.0.0:5672?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
            <transportConnector name="stomp" uri="stomp://0.0.0.0:61613?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
            <transportConnector name="mqtt" uri="mqtt://0.0.0.0:1883?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
            <transportConnector name="ws" uri="ws://0.0.0.0:61614?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/> -->
        </transportConnectors>
        <!-- destroy the spring context on shutdown to stop jetty -->
        <shutdownHooks>
            <bean xmlns="http://www.springframework.org/schema/beans" class="org.apache.activemq.hooks.SpringContextHook" />
        </shutdownHooks>
    </broker>
    <!--
        Enable web consoles, REST and Ajax APIs and demos
        The web consoles requires by default login, you can disable this in the jetty.xml file
        Take a look at ${ACTIVEMQ_HOME}/conf/jetty.xml for more details
    -->
    <import resource="jetty.xml"/>
</beans>

当我让经纪人和消费者都在运行，然后停止经纪人时，我的消费者会在几分钟后退出。据我所知，它必须尝试重新连接，但事实并非如此。我做错了什么，请劝告。

注意！我在Eclipse中启动了我的消费者，我没有为此任务构建一个独立的jar。

我已经将我的经纪人更新到最新的5.9.1，并对我的消费者进行了同样的更新。结果是一样的——在我停止经纪人后，我的消费者在几秒钟后死亡。若broker已经启动并运行，它就可以正常工作。

Answer 1

对于任何无法通过ConnectionFactory中的URI/URL参数设置故障转移的人，因为在ARTEMIS中找不到架构：

据我所知，在ActiveMQ中，URL如下：

failover:(tcp://localhost:61616,tcp://localhost:51516)?randomize=false

但在Artemis中，由于找不到架构，上述操作将失败，因此只删除failover:前缀：

(tcp://localhost:61616,tcp://localhost:51516)?randomize=false

Answer 2

好吧，问题实际上在我的代码中：没有什么可以阻止主线程退出。由于实现故障转移的线程是一个守护进程线程，所以消费者应用程序在没有任何可保留的东西（没有非守护进程线程）之后立即终止。

Answer 3

很可能您使用的ActiveMQ版本存在错误，导致存在所有守护进程线程，这意味着没有任何东西可以保持客户端运行。升级到更高版本，如v5.9.1，看看这是否有帮助。如果不发布更多的信息，因为你还没有真正提供太多。