JBoss MDB - Middleware Wonders

This post describes usage of Jboss JMS Feature using a Message Driven Bean (MDB) consumer.

Note: In this article , we would be using the default JMS queue ‘/queue/DLQ’.

1. Create a Message Driven Bean with bean class TestMDB.java

import java.io.PrintStream;
import javax.ejb.MessageDrivenBean;
import javax.jms.*;
import weblogic.ejb.GenericMessageDrivenBean;
import javax.ejb.MessageDrivenBean;
import javax.ejb.MessageDrivenContext;
import javax.ejb.EJBException;
import javax.jms.MessageListener;
import javax.jms.Message;
public class TestMDB implements MessageDrivenBean, MessageListener {
private MessageDrivenContext ctx = null;
public TestMDB() {
}
//--- MessageDrivenBean
public void setMessageDrivenContext(MessageDrivenContext ctx)
throws EJBException {
this.ctx = ctx;
}
public void ejbCreate() {}
public void ejbRemove() {ctx=null;}
//--- MessageListener
public void onMessage(Message msg)
{
try
{
System.out.println("****** Inside onMessage() *********");
String msgText;
if(msg instanceof TextMessage)
msgText = ((TextMessage)msg).getText();
else
msgText = msg.toString();
System.out.println((new StringBuilder("Message Received: ")).append(msgText).toString());
}
catch(JMSException jmse)
{
jmse.printStackTrace();
}
}
}

2. Generate the ejb-jar.xml as below.

<?xml version="1.0" encoding="UTF-8"?>

<ejb-jar

xmlns="http://java.sun.com/xml/ns/j2ee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/ejb-jar_2_1.xsd"

version="2.1">

<enterprise-beans>

<message-driven>

<ejb-name>TestMDB</ejb-name>

<ejb-class>TestMDB</ejb-class>

<transaction-type>Container</transaction-type>

<activation-config>

<activation-config-property>

<activation-config-property-name>destinationType</activation-config-property-name>

<activation-config-property-value>javax.jms.Queue</activation-config-property-value>

</activation-config-property>

</activation-config>

</message-driven>

</enterprise-beans>

</ejb-jar>

Note: Specify the ejb bean class name in the attribute <ejb-class> of the element <message-driven>.

3. Generate the jboss.xml to specify the name of the Jboss Queue, which the MDB bean would be listening to.

<?xml version="1.0" encoding="Cp1252"?>

<jboss>

<enterprise-beans>

<message-driven>

<ejb-name>TestMDB</ejb-name>

<configuration-name>Standard Message Driven Bean</configuration-name>

<destination-jndi-name>/queue/DLQ</destination-jndi-name>

</message-driven>

</enterprise-beans>

</jboss>

4. Create a jar file as below.

jar -cvf TestMDB.jar .

5. Copy the jar file and paste it under Deploy folder of any server profiles.

$JBOSS_HOMEserverdefaultdeploy

The deployment is automatically picked up by the server and you would see the relevant messages in the server logs and the console.

****************************************************************************

21:09:18,968 INFO [EjbDeployer] installing bean: ejb/#TestMDB,uid6458583

21:09:18,968 INFO [EjbDeployer] with dependencies:

21:09:18,968 INFO [EjbDeployer] and supplies:

21:09:18,968 INFO [EjbDeployer] jndi:null

21:09:19,046 INFO [EjbModule] Deploying TestMDB

****************************************************************************

6. Open a command prompt and set the class path to the jbossall-client.jar file.

set classpath=%classpath%;G:jboss-5.1.0.GAclientjbossall-client.jar

7. Compile and execute the below QueueSend.java program

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.Hashtable;

import javax.jms.*;

import javax.naming.Context;

import javax.naming.InitialContext;

import javax.naming.NamingException;

import java.util.Properties;

public class QueueSend

{

public final static String JNDI_FACTORY="org.jboss.naming.HttpNamingContextFactory";

public final static String JMS_FACTORY="ConnectionFactory";

public final static String QUEUE="/queue/DLQ";

private QueueConnectionFactory qconFactory;

private QueueConnection qcon;

private QueueSession qsession;

private QueueSender qsender;

private Queue queue;

private TextMessage msg;

public void init(Context ctx, String queueName)

throws NamingException, JMSException

{

qconFactory = (QueueConnectionFactory) ctx.lookup(JMS_FACTORY);

qcon = qconFactory.createQueueConnection();

qsession = qcon.createQueueSession(false, Session.AUTO_ACKNOWLEDGE);

queue = (Queue) ctx.lookup(queueName);

qsender = qsession.createSender(queue);

msg = qsession.createTextMessage();

qcon.start();

}

public void send(String message) throws JMSException {

msg.setText(message);

qsender.send(msg);

}

public void close() throws JMSException {

qsender.close();

qsession.close();

qcon.close();

}

public static void main(String[] args) throws Exception {

if (args.length != 1) {

System.out.println("Usage: java examples.jms.queue.QueueSend JBossURL");

return;

}

InitialContext ic = getInitialContext(args[0]);

QueueSend qs = new QueueSend();

qs.init(ic, QUEUE);

readAndSend(qs);

qs.close();

}

private static void readAndSend(QueueSend qs)

throws IOException, JMSException

{

BufferedReader msgStream = new BufferedReader(new InputStreamReader(System.in));

String line=null;

boolean quitNow = false;

do {

System.out.print("Enter message ("quit" to quit): n");

line = msgStream.readLine();

if (line != null && line.trim().length() != 0) {

qs.send(line);

System.out.println("JMS Message Sent: "+line+"n");

quitNow = line.equalsIgnoreCase("quit");

}

} while (! quitNow);

}

private static InitialContext getInitialContext(String url)

throws NamingException

{

Properties env = new Properties();

env.setProperty(Context.INITIAL_CONTEXT_FACTORY, JNDI_FACTORY);

env.setProperty(Context.PROVIDER_URL,url);

return new InitialContext(env);

}

}

****************************************************************************

java QueueSend http://127.0.0.1:8080/invoker/JNDIFactory

The deployed MDB will consume the messages from the Jboss Queue as shown below.

For reference I have uploaded the sample TestMDB.jar to the below link.

http://www.4shared.com/file/TjO6i_DR/TestMDB.html

Best Regards,

Wonders

Related