Implementing JMS with Spring: Message Driven POJO

The previous post described how to implement a JMS messaging client using Spring JMS. This post will describe how to implement the Message listener as a spring Message driven POJO. Follow these steps to implement the Message driven POJO

1. Create the Message Driven POJO: The only requirement for the Message Driven POJO is to implement the MessageListener interface. The following listing shows the code for the MDP

   public class SpringMDP implements MessageListener {
   public void onMessage(Message message) {
   try {
   System.out.println(((TextMessage) message).getText());
   } catch (JMSException ex) {
   throw new RuntimeException(ex);
   }
   }
   }

   SpringMDP.java
2. Create the bean definition in applicationContext.xml file.

   <?xml version="1.0" encoding="UTF-8"?>
   <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN"
   "http://www.springframework.org/dtd/spring-beans.dtd">
   <beans>
     <!-- this is the Message Driven POJO (MDP) -->
     <bean id="messageListener" class="jms.SpringMDP" />
   
   <bean id="jndiTemplate" class="org.springframework.jndi.JndiTemplate">
   <property name="environment">
   <props>
   <prop key="java.naming.factory.initial">weblogic.jndi.WLInitialContextFactory</prop>
   <prop key="java.naming.provider.url">t3://localhost:20001</prop>
   </props>
   </property>
   </bean>
   <bean id="connectionFactory" class="org.springframework.jndi.JndiObjectFactoryBean">
   <property name="jndiTemplate">
   <ref bean="jndiTemplate" />
   </property>
   <property name="jndiName">
   <value>jms/connectionFactory</value>
   </property>
   </bean>
   
   <bean id="queue" class="org.springframework.jndi.JndiObjectFactoryBean">
   <property name="jndiTemplate">
   <ref bean="jndiTemplate" />
   </property>
   <property name="jndiName">
   <value>jms/testQueue</value>
   </property>
   </bean>
   
   
     <bean id="listenerContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
       <property name="concurrentConsumers" value="5" />
       <property name="connectionFactory" ref="connectionFactory" />
       <property name="destination" ref="queue" />
       <property name="messageListener" ref="messageListener" />
     </bean>
   </beans>
   

   WEB-INF/applicationContext.xml
   The Message listener container handles all the required functions for making the Simple POJO a Message Driven POJO.
3. Update Web.xml to include a listener for spring.

   <listener>  <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
   </listener>