Spring JMS with ActiveMQ

ActiveMq is a powerful open source messaging broker, and is very easy and straightforward to use with Spring as the below classes and XML will prove. The example below is the bar minimum needed to get up and running with transactions and message converters.

On the sending side, the ActiveMq connection factory needs to be created with the url of the broker. This in turn is used to create the Spring JMS connection factory and as no session cache property is supplied the default cache is one. The template is then used in turn to create the Message Sender class:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:amq="http://activemq.apache.org/schema/core" 
 xmlns:context="http://www.springframework.org/schema/context"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns:tx="http://www.springframework.org/schema/tx"
 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-5.5.0.xsd  
  http://www.springframework.org/schema/context 
  http://www.springframework.org/schema/context/spring-context.xsd  
  http://www.springframework.org/schema/jms 
  http://www.springframework.org/schema/jms/spring-jms.xsd
  http://www.springframework.org/schema/tx
  http://www.springframework.org/schema/tx/spring-tx.xsd">

    <!-- Activemq connection factory -->
    <bean id="amqConnectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
        <constructor-arg index="0" value="${jms.broker.url}"/>
    </bean>

    <!-- ConnectionFactory Definition -->
    <bean id="connectionFactory" class="org.springframework.jms.connection.CachingConnectionFactory">
        <constructor-arg ref="amqConnectionFactory" />
    </bean>

    <!--  Default Destination Queue Definition-->
    <bean id="defaultDestination" class="org.apache.activemq.command.ActiveMQQueue">
        <constructor-arg index="0" value="${jms.queue.name}"/>
    </bean>

    <!-- JmsTemplate Definition -->
    <bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate">
        <property name="connectionFactory" ref="connectionFactory" />
        <property name="defaultDestination" ref="defaultDestination" /> 
    </bean>

    <!-- Message Sender Definition -->
    <bean id="messageSender" class="com.city81.jms.MessageSender">
        <constructor-arg index="0" ref="jmsTemplate" />
    </bean>

</beans> 

An example sending class is below. It uses the convertandSend method of the JmsTemplate class. As there is no destination arg, the message will be sent to the default destination which was set up in the XML file:

import java.util.Map;
import org.springframework.jms.core.JmsTemplate;

public class MessageSender {

    private final JmsTemplate jmsTemplate;

    public MessageSender(final JmsTemplate jmsTemplate) {
        this.jmsTemplate = jmsTemplate;
    }

    public void send(final Map map) {
        jmsTemplate.convertAndSend(map);
    }

}

On the receiving side, there needs to be a listener container. The simplest example of this is the SimpleMessageListenerContainer. This requires a connection factory, a destination (or destination name) and a message listener.

An example of the Spring configuration for the receiving messages is below:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:amq="http://activemq.apache.org/schema/core"

 xmlns:jms="http://www.springframework.org/schema/jms"
 xmlns:context="http://www.springframework.org/schema/context"
 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-5.5.0.xsd  
  http://www.springframework.org/schema/context 
  http://www.springframework.org/schema/context/spring-context.xsd  
  http://www.springframework.org/schema/jms 
  http://www.springframework.org/schema/jms/spring-jms.xsd">

    <!-- Activemq connection factory -->
    <bean id="amqConnectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
        <constructor-arg index="0" value="${jms.broker.url}"/>
    </bean>

    <!-- ConnectionFactory Definition -->
    <bean id="connectionFactory" class="org.springframework.jms.connection.CachingConnectionFactory">
        <constructor-arg ref="amqConnectionFactory" />
    </bean>  

    <!-- Message Receiver Definition -->
    <bean id="messageReceiver" class="com.city81.jms.MessageReceiver">
    </bean>

    <bean class="org.springframework.jms.listener.SimpleMessageListenerContainer">
        <property name="connectionFactory" ref="connectionFactory" />
        <property name="destinationName" value="${jms.queue.name}" />
        <property name="messageListener" ref="messageReceiver" />
    </bean>

</beans> 

The listening/receiving class needs to extend javax.jms.MessageListener and implement the onMessage method:

import javax.jms.MapMessage;
import javax.jms.Message;
import javax.jms.MessageListener;

public class MessageReceiver implements MessageListener {

    public void onMessage(final Message message) {
        if (message instanceof MapMessage) {
            final MapMessage mapMessage = (MapMessage) message;
            // do something
        }
    }

}

To then send a message would be as simple as getting the sending bean from the bean factory as shown in the below code:

    MessageSender sender = (MessageSender) factory.getBean("messageSender");
    Map map = new HashMap();
    map.put("Name", "MYNAME");
    sender.send(map);

Will try to expand and build up JMS and Spring articles with examples of using transactions and other brokers like MQSeries.