In this example we shall show you how to create a simple hello World example in JMS, using JBoss 5.1. JMS is a very popular API standard for messaging, and most messaging systems provide a JMS API. To create a simple JMS example that produces and consumes a simple hello World message one should perform the following steps:
- Create a JNDI InitialContext from which to lookup our JMS objects. We are using the
InitialContext(Hashtable<?,?> environment)constructor with a Hashtable where we have set the properties needed for connecting to JBoss, such as the initial context factory to use, the service provider that is the localhost, on port 1099 and the package prefix to use when loading in the context factory. - Lookup the JMS connection factory from the JBoss 5.1 object store, using
lookup(String name)API method of Context. - Lookup a queue from the JBoss 5.1 object store, using
lookup(String name)API method of Context. - Create a connection to the JBoss 5.1 Message Service, using
createConnection()API method ofjavax.jms.ConnectionFactory. - Create a non transacted JMS Session, with
AUTO_ACKNOWLEDGEacknowledge mode within the connection, usingcreateSession(boolean arg0, int arg1)API method ofjavax.jms.Connection. - Create a message producer to put messages on the queue, with
createProducer(Destination arg0)API method ofjavax.jms.Session. - Create a message, with
createTextMessage()API method ofjavax.jms.SessionandsetText(String arg0)API method ofjavax.jms.TextMessageand send it to the queue, withsend(Message arg)method of javax.jms.MessageProducer. - Create a message consumer that will consume orders from the queue, with
createConsumer(Destination arg0)API method ofjavax.jms.Session. - Make sure to start the connection, or delivery won’t occur on it. Use
start()method ofjavax.jms.Connection. - Receive the message from the queue, using
receive()API method ofjavax.jms.MessageConsumerand get the contents of the message, withgetText()API method ofjavax.jms.TextMessage. - Close the session and connection resources, using
close()API methods ofjavax.jms.Sessionandjavax.jms.Connection.
Let’s take a look at the code snippet that follows:
package com.javacodegeeks.snippets.enterprise;
import java.util.Hashtable;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.naming.Context;
import javax.naming.InitialContext;
public class HelloWorldJMS {
public static void main(String[] args) {
try {
/*
* Connecting to JBoss naming service running on local host and on
* default port 1099 the environment that should be created is like the
* one shown below :
*/
Hashtable env = new Hashtable();
env.put(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
env.put(Context.PROVIDER_URL, "jnp://localhost:1099");
env.put(Context.URL_PKG_PREFIXES, "org.jboss.naming:org.jnp.interfaces");
// Create the initial context
Context ctx = new InitialContext(env);
// Lookup the JMS connection factory from the JBoss 5.1 object store
ConnectionFactory connectionFactory = (ConnectionFactory) ctx.lookup("ConnectionFactory");
// Lookup a queue from the JBoss 5.1 object store
Queue queue = (javax.jms.Queue)ctx.lookup("/queue/DLQ");
// Create a connection to the JBoss 5.1 Message Service
Connection connection = connectionFactory.createConnection();
// Create a session within the connection
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
// Create a message producer to put messages on the queue
MessageProducer messageProducer = session.createProducer(queue);
//Create and send a message to the queue
TextMessage textMessage = session.createTextMessage();
textMessage.setText("Hello World");
System.out.println("Sending Message: " + textMessage.getText());
messageProducer.send(textMessage);
// Create a message consumer
MessageConsumer messageConsumer = session.createConsumer(queue);
// Start the Connection created
connection.start();
// Receive a message from the queue.
Message msg = messageConsumer.receive();
// Retrieve the contents of the message.
if (msg instanceof TextMessage) {
TextMessage txtMsg = (TextMessage) msg;
System.out.println("Read Message: " + txtMsg.getText());
}
//Close the session and connection resources.
session.close();
connection.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
Output:
Sending Message: Hello World
Read Message: Hello World
This was an example of how to create a simple JMS example using JBoss 5.1.
