The latest AS 7.0.1 release made finally available the last EJB component which was missing: Message Driven Beans. Let's see how to develop a simple MDB on AS 7 with this 5 minute tutorial!
In the current AS 7 release, the messaging domain is included into the *-preview.xml configuration files. In the future 7.1 release, the messaging configuration will be merged in the main configuration file.
However that's not a big issue: for example if you want to run JMS applications on AS 7 standalone, you should start your server using the standalone-preview.xml configuration file.
In practice this just requires using the --server-config when starting your server. For example:
standalone.bat --server-config=standalone-preview.xml
Ok, so we want to roll MDB. Here's a very simple one which does a simple job of printing the text message received:
package com.mdb;
import javax.ejb.ActivationConfigProperty;
import javax.ejb.MessageDriven;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;
@MessageDriven(name = "MessageMDBSample", activationConfig = {
@ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue"),
@ActivationConfigProperty(propertyName = "destination", propertyValue = "queue/sampleQueue"),
@ActivationConfigProperty(propertyName = "acknowledgeMode", propertyValue = "Auto-acknowledge") })
public class MDBSample implements MessageListener {
public void onMessage(Message message) {
TextMessage tm = (TextMessage) message;
try {
System.out.println("Received message "+tm.getText());
} catch (JMSException e) {
e.printStackTrace();
}
}
}
This MDB consumes messages from the queue sampleQueue. In order to add this queue from the CLI just issue:
[standalone@localhost:9999 /] add-jms-queue --name=sampleQueue --entries=queue/sampleQueue
If you want to skip this step, you could just use the queue/test which is by default configured in the AS 7.
Ok. Now all you need is a JMS sender. To make things super fast just add a Servlet to your application:
package com.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.jms.*;
import javax.naming.*;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
@WebServlet("/JMSClientServlet")
public class JMSClientServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String destinationName = "queue/sampleQueue";
PrintWriter out = response.getWriter();
Context ic = null;
ConnectionFactory cf = null;
Connection connection = null;
try {
ic = new InitialContext();
cf = (ConnectionFactory)ic.lookup("/ConnectionFactory");
Queue queue = (Queue)ic.lookup(destinationName);
connection = cf.createConnection();
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
MessageProducer publisher = session.createProducer(queue);
connection.start();
TextMessage message = session.createTextMessage("Hello AS 7 !");
publisher.send(message);
out.println("Message sento to the JMS Provider");
}
catch (Exception exc) {
exc.printStackTrace();
}
finally {
if (connection != null) {
try {
connection.close();
} catch (JMSException e) {
e.printStackTrace();
}
}
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}By invoking your Servlet one JMS message will be sent to the defined queue, resulting in:
16:03:22,853 INFO [stdout] (Thread-3 (group:HornetQ-client-global-threads-903047498)) Received message Hello AS 7 !<
