How to create EJB3 MDB Queue project in Eclipse (JBoss 7.1)

By Nithya Vasudevan

Environment Used

  • JDK 6 (Java SE 6)
  • JMS Sender/Client – Servlet 2.5 API
  • JMS Consumer – EJB 3.0 Message Driven Bean (MDB)
  • Eclipse Indigo IDE for Java EE Developers (3.7.1)
  • JBoss Tools – Core 3.3.0 M5 for Eclipse Indigo (3.7.1)
  • JBoss Application Server (AS) 7.1.0 Final

Setting up development environment:
Read this page for installing and setting up the environment for developing and deploying EJB 3.0 Session bean on JBoss application server.

Project Description

  • We are going to create a simple EJB 3 Message Driven Bean and a Web client (Servlet) which sends messages to the Queue destination.
  • This example explains how to develop, deploy and run EJB3 MDB as a message consumer in JBoss application server.
  • For testing this MDB listener we write a Web client (a servlet) as a message producer which sends a simple text message and an object message.
  • The message driven bean (message consumer) and the Servlet (message producer) are deployed on the same server instance (JBoss AS).

Creating New EJB Project

  • Open Eclipse IDE and create a new EJB project which can be done in three ways,
    • Right click on Project Explorer -> New -> EJB Project
    • File menu -> New -> EJB Project
    • Click on the down arrow on New icon on toolbar -> EJB Project

  • Enter the project name as “FirstMDBProject” and make sure the JBoss 7.1 Runtime has been selected with the EJB 3.0 Module version.
  • This project uses Java 1.6 version. The default Java version in Eclipse Indigo is 1.7 so to change the “Configuration” click on “Modify…” button to make changes.
  • Click Next -> Next -> and Finish.
  • You will see an EJB project in the Project Explorer view.

Creating object message class

  • Right click on ejbModule -> New -> Class
  • Enter the Java package name as com.theopentutorials.mdb.to
  • Enter the Class name as Employee
  • Click “Finish“

Copy the following code:

package com.theopentutorials.mdb.to;
import java.io.Serializable;
public class Employee implements Serializable {
	private int id;
	private String name;
	private String designation;
	private double salary;
	
	public Employee() {	}
	
	public Employee(int id, String name, String designation, 
			double salary) 
	{
		this.id = id;
		this.name = name;
		this.designation = designation;
		this.salary = salary;
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getDesignation() {
		return designation;
	}
	public void setDesignation(String designation) {
		this.designation = designation;
	}
	public double getSalary() {
		return salary;
	}
	public void setSalary(double salary) {
		this.salary = salary;
	}
	@Override
	public String toString() {
		return "Employee [id=" + id + ", name=" + name + ", designation="
				+ designation + ", salary=" + salary + "]";
	}
}

Creating Message Driven Bean Consumer

  • Right click on ejbModule -> New -> Message-Driven Bean (EJB 3.x)
  • Enter the Java package name as com.theopentutorials.mdb
  • Enter the Class name as QueueListenerMDB
  • Select the Destination type as Queue
  • Click “Finish“

package com.theopentutorials.mdb;

import java.util.Date;
import javax.ejb.ActivationConfigProperty;
import javax.ejb.MessageDriven;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.ObjectMessage;
import javax.jms.TextMessage;
import com.theopentutorials.mdb.to.Employee;

@MessageDriven(activationConfig = {
		@ActivationConfigProperty(
		propertyName = "destinationType", propertyValue = "javax.jms.Queue"),
		@ActivationConfigProperty(
		propertyName = "destination", propertyValue = "queue/MyQueue") })
public class QueueListenerMDB implements MessageListener {
	public QueueListenerMDB() {
	}

	public void onMessage(Message message) {
		try {
			if (message instanceof TextMessage) {
				System.out.println("Queue: I received a TextMessage at " 
								+ new Date());
				TextMessage msg = (TextMessage) message;
				System.out.println("Message is : " + msg.getText());
			} else if (message instanceof ObjectMessage) {
				System.out.println("Queue: I received an ObjectMessage at " 
								+ new Date());
				ObjectMessage msg = (ObjectMessage) message;
				Employee employee = (Employee) msg.getObject();
				System.out.println("Employee Details: ");
				System.out.println(employee.getId());
				System.out.println(employee.getName());
				System.out.println(employee.getDesignation());
				System.out.println(employee.getSalary());
			} else {
				System.out.println("Not a valid message for this Queue MDB");
			}

		} catch (JMSException e) {
			e.printStackTrace();
		}
	}
}
  • The activationConfig property of @MessageDriven is an array of ActivationConfigProperty and it should specify the destinationType (Queue or Topic) and destination (Queue/Topic’s JNDI name).
  • In the onMessage() we are receiving two types of message, TextMessage and ObjectMessage.

Configuring messaging services on JBoss AS 7

In the previous version of JBoss AS we had an option to configure the messaging destinations (Queue or Topic) in META-INF/*-service.xml with element. In JBoss AS 7, it is configured in main application server configuration file (standalone.xml) which is found in JBossAS_Home/standalone/configuration.

  • Open standalone.xml and follow the steps below to configure messaging services.

Add entension element

Add

<extension module="org.jboss.as.messaging"/>

in the <extensions> element.

Add subsystem element

Add the following <subsystem> inside <profile> element.

<subsystem xmlns="urn:jboss:domain:messaging:1.1">
            <hornetq-server>
                <persistence-enabled>true</persistence-enabled>
                <journal-file-size>102400</journal-file-size>
                <journal-min-files>2</journal-min-files>

                <connectors>
                    <netty-connector name="netty" socket-binding="messaging"/>
                    <netty-connector name="netty-throughput" socket-binding="messaging-throughput">
                        <param key="batch-delay" value="50"/>
                    </netty-connector>
                    <in-vm-connector name="in-vm" server-id="0"/>
                </connectors>

                <acceptors>
                    <netty-acceptor name="netty" socket-binding="messaging"/>
                    <netty-acceptor name="netty-throughput" socket-binding="messaging-throughput">
                        <param key="batch-delay" value="50"/>
                        <param key="direct-deliver" value="false"/>
                    </netty-acceptor>
                    <in-vm-acceptor name="in-vm" server-id="0"/>
                </acceptors>

                <security-settings>
                    <security-setting match="#">
                        <permission type="send" roles="guest"/>
                        <permission type="consume" roles="guest"/>
                        <permission type="createNonDurableQueue" roles="guest"/>
                        <permission type="deleteNonDurableQueue" roles="guest"/>
                    </security-setting>
                </security-settings>

                <address-settings>
                    <address-setting match="#">
                        <dead-letter-address>jms.queue.DLQ</dead-letter-address>
                        <expiry-address>jms.queue.ExpiryQueue</expiry-address>
                        <redelivery-delay>0</redelivery-delay>
                        <max-size-bytes>10485760</max-size-bytes>
                        <address-full-policy>BLOCK</address-full-policy>
                        <message-counter-history-day-limit>10</message-counter-history-day-limit>
                    </address-setting>
                </address-settings>

                <jms-connection-factories>
                    <connection-factory name="InVmConnectionFactory">
                        <connectors>
                            <connector-ref connector-name="in-vm"/>
                        </connectors>
                        <entries>
                            <entry name="java:/ConnectionFactory"/>
                        </entries>
                    </connection-factory>
                    <connection-factory name="RemoteConnectionFactory">
                        <connectors>
                            <connector-ref connector-name="netty"/>
                        </connectors>
                        <entries>
                            <entry name="RemoteConnectionFactory"/>
                            <entry name="java:jboss/exported/jms/RemoteConnectionFactory"/>
                        </entries>
                    </connection-factory>
                    <pooled-connection-factory name="hornetq-ra">
                        <transaction mode="xa"/>
                        <connectors>
                            <connector-ref connector-name="in-vm"/>
                        </connectors>
                        <entries>
                            <entry name="java:/JmsXA"/>
                        </entries>
                    </pooled-connection-factory>
                </jms-connection-factories>

                <jms-destinations>
                    <jms-queue name="testQueue">
                        <entry name="queue/MyQueue"/>
                    </jms-queue>
                    <jms-topic name="testTopic">
                        <entry name="topic/MyTopic"/>
                    </jms-topic>
                </jms-destinations>
            </hornetq-server>
        </subsystem>

The entry name for jms-queue should match the destination activation config property in @MessageDriven.

Add messaging port

In <socket-binding-group> add these two elements

<socket-binding name="messaging" port="5445"/>
<socket-binding name="messaging-throughput" port="5455"/>

Add MDB Resource Adapter Reference

Under <subsystem xmlns=”urn:jboss:domain:ejb3:1.2″> add this <mdb> element

<mdb>
    <resource-adapter-ref resource-adapter-name="hornetq-ra"/>
    <bean-instance-pool-ref pool-name="mdb-strict-max-pool"/>
</mdb>

Deploying EJB project

  • Now we need to deploy the EJB project “FirstMDBProject” on server..
  • Deploying the project can be done in two ways,
    • Right click on the EJB project -> Run As -> Run On Server. Select the existing “JBoss 7.1 Runtime Server” and click Finish.
    • Right click on “JBoss 7.1 Runtime Server” available in Servers view -> Add and Remove… -> Select the EJB JAR file from the left pane and click Add-> and then Finish.

Start/Restart the Server

Right click on “JBoss 7.1 Runtime Server” from Servers view and click on Start if it has not yet been started.

If the project is deployed properly with global JNDI mapping then you will see the following message in the console.

Bound messaging object to jndi name java:/queue/MyQueue
Started message driven bean ‘QueueListenerMDB’ with ‘hornetq-ra’ resource adapter
Deployed “FirstMDBProject.jar”

Creating JMS client (Dynamic Web Project)

  • The next step is to write a Web Client (a Servlet) which produces the message and sends to the Queue.
  • The servlet uses JNDI to lookup ConnectionFactory and the Queue.
  • Creating a new ‘Dynamic Web project’ can be done in three ways,
    • Right click on Project Explorer -> New -> Dynamic Web Project
    • File menu -> New -> Dynamic Web Project
    • Click on the down arrow on New icon on toolbar -> Dynamic Web Project

  • Enter the project name as “MDBWebClient” and make sure the JBoss 7.1 Runtime has been selected with the Dynamic web module version as 2.5.
  • This project uses Java 1.6 version. The default Java version in Eclipse Indigo is 1.7 so to change the “Configuration” click on “Modify…” button to make changes.
  • Click “Next” -> “Next” -> and “Finish”.
  • You will see the Dynamic web project in the “Project Explorer” view.

To send object message servlet needs Employee class which we have created in FirstMDBProject.

Creating JAR file

  • Right click on Employee.java file in FirstMDBProject -> Export.
  • Expand Java folder and select “JAR file” and click Next.
  • Click on Browse… and enter the file name and Finish.

Now copy the created JAR file and paste it in MDBWebClient/WebContent/WEB-INF/lib folder.

Creating Servlet class

  • Right click on src or Project -> New -> Servlet

  • Enter the Java package name as com.theopentutorials.servlets
  • Enter the Class name as ServletMessageProducer
  • Click “Finish“

In the doGet() method copy the following code.

package com.theopentutorials.servlets;

import java.io.IOException;
import java.io.PrintWriter;
import javax.jms.ObjectMessage;
import javax.jms.Queue;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.QueueSender;
import javax.jms.QueueSession;
import javax.jms.TextMessage;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.theopentutorials.mdb.to.Employee;

public class ServletMessageProducer extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    public ServletMessageProducer() {
        super();
    }

	protected void doGet(HttpServletRequest request, 
			HttpServletResponse response) 
			throws ServletException, IOException {
		final String QUEUE_LOOKUP = "queue/MyQueue";
		final String CONNECTION_FACTORY = "ConnectionFactory";
		
		PrintWriter out = response.getWriter();
		try{
			Context context = new InitialContext();
			QueueConnectionFactory factory = 
				(QueueConnectionFactory)context.lookup(CONNECTION_FACTORY);
			QueueConnection connection = factory.createQueueConnection();
			QueueSession session = 
				connection.createQueueSession(false, 
					QueueSession.AUTO_ACKNOWLEDGE);
			
			Queue queue = (Queue)context.lookup(QUEUE_LOOKUP);
			QueueSender sender = session.createSender(queue);
			
			//1. Sending TextMessage to the Queue 
			TextMessage message = session.createTextMessage();
			message.setText("Hello EJB3 MDB Queue!!!");
			sender.send(message);
			out.println("1. Sent TextMessage to the Queue");
			
			//2. Sending ObjectMessage to the Queue
			ObjectMessage objMsg = session.createObjectMessage();
			
			Employee employee = new Employee();
			employee.setId(2163);
			employee.setName("Kumar");
			employee.setDesignation("CTO");
			employee.setSalary(100000);
			objMsg.setObject(employee);						
			sender.send(objMsg);
			out.println("2. Sent ObjectMessage to the Queue");
			
			session.close();
		}catch(Exception e){e.printStackTrace();}
	}
}

Deploying Dynamic Web Project

  • Now we need to deploy the servlet’s project “MDBWebClient” on server.
  • Deploying the project can be done in two ways,
    • Right click on the “MDBWebClient” Dynamic Web project -> Run As -> Run On Server. Select the existing “JBoss 7.1 Runtime Server” and click Finish.
    • Right click on “JBoss 7.1 Runtime Server” available in Servers view -> Add and Remove… -> Select the WAR file from the left pane and click Add-> and then Finish.

Start/Restart the Server

  • Right click on “JBoss 7.1 Runtime Server” from Servers view and click on Start if it has not yet been started.
  • If the projects are deployed properly then you will see the following message in the console.

Deployed “MDBWebClient.war”
Deployed “FirstMDBProject.jar”

Folder Structure

The figure below shows the final directory structure of EJB project “FirstMDBProject”.

The figure below shows the final directory structure of Dynamic Web project “MDBWebClient”

Run the Servlet

Eclipse Internal Web Browser will display the following output

JBoss Runtime Server Console will display the following output.

[stdout] Queue: I received a TextMessage at Fri Feb 17 18:03:41 IST 2012
[stdout] Message is : Hello EJB3 MDB Queue!!!
[stdout] Queue: I received an ObjectMessage at Fri Feb 17 18:03:41 IST 2012
[stdout] Employee Details:
[stdout] 2163
[stdout] Kumar
[stdout] CTO
[stdout] 100000.0

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