Activemq client configuration and usage

1. Use activemq through JNDI

1. Configure the JMS object in JNDI

java.naming.factory.initial = org.apache.activemq.jndi.ActiveMQInitialContextFactory # use the following property to configure the default connectorjava.naming.provider.url = vm://localhost # use the following property to specify the JNDI name the connection factory# should appear as.#connectionFactoryNames = connectionFactory, queueConnectionFactory, topicConnectionFactry # register some queues in JNDI using the form# queue.[jndiName] = [physicalName]queue.MyQueue = example.MyQueue  # register some topics in JNDI using the form# topic.[jndiName] = [physicalName]topic.MyTopic = example.MyTopic

2. client code usage

// create a new intial context, which loads from jndi.properties filejavax.naming.Context ctx = new javax.naming.InitialContext();// lookup the connection factoryjavax.jms.TopicConnectionFactory factory = (javax.jms.TopicConnectionFactory)ctx.lookup("ConnectionFactory");// create a new TopicConnection for pub/sub messagingjavax.jms.TopicConnection conn = factory.getTopicConnection();// lookup an existing topicjavax.jms.Topic mytopic = (javax.jms.Topic)ctx.lookup("MyTopic");// create a new TopicSession for the clientjavax.jms.TopicSession session = conn.createTopicSession(false,TopicSession.AUTO_ACKNOWLEDGE);// create a new subscriber to receive messagesjavax.jms.TopicSubscriber subscriber = session.createSubscriber(mytopic);

Notice the name of the topic in the sample is "mytopic ". activemq will read the JNDI. properties files and creates the topics and queues in a lazy fashion. the prefix topic and queue is stripped, so the JNDI name begins after the prefix.

Once you have the JNDI. properties edited and ready, it needs to be accessible to your application. the easiest way is to add JNDI. properties to a jar file. when "New initialcontext ()" is called, it will scan the resources and find the file. if you get "javax. naming. namingexception ", it usually means the JNDI. properties file is not accessible.

 

3. Set Through porperties

Properties props = new Properties();props.setProperty(Context.INITIAL_CONTEXT_FACTORY,"org.apache.activemq.jndi.ActiveMQInitialContextFactory");props.setProperty(Context.PROVIDER_URL,"tcp://hostname:61616");javax.naming.Context ctx = new InitialContext(props);

4. example Java code

import javax.jms.Connection;import javax.jms.ConnectionFactory;import javax.jms.Destination;import javax.jms.JMSException;import javax.jms.MessageProducer;import javax.jms.Session;import javax.jms.TextMessage;import javax.naming.Context;import javax.naming.InitialContext;import javax.naming.NamingException; import org.slf4j.Logger;import org.slf4j.LoggerFactory; /** * A simple polymorphic JMS producer which can work with Queues or Topics which * uses JNDI to lookup the JMS connection factory and destination * * */public final class SimpleProducer {     private static final Logger LOG = LoggerFactory.getLogger(SimpleProducer.class);     private SimpleProducer() {    }     /**     * @param args the destination name to send to and optionally, the number of     *                messages to send     */    public static void main(String[] args) {        Context jndiContext = null;        ConnectionFactory connectionFactory = null;        Connection connection = null;        Session session = null;        Destination destination = null;        MessageProducer producer = null;        String destinationName = null;        final int numMsgs;         if ((args.length < 1) || (args.length > 2)) {            LOG.info("Usage: java SimpleProducer <destination-name> [<number-of-messages>]");            System.exit(1);        }        destinationName = args[0];        LOG.info("Destination name is " + destinationName);        if (args.length == 2) {            numMsgs = (new Integer(args[1])).intValue();        } else {            numMsgs = 1;        }         /*         * Create a JNDI API InitialContext object         */        try {            jndiContext = new InitialContext();        } catch (NamingException e) {            LOG.info("Could not create JNDI API context: " + e.toString());            System.exit(1);        }         /*         * Look up connection factory and destination.         */        try {            connectionFactory = (ConnectionFactory)jndiContext.lookup("ConnectionFactory");            destination = (Destination)jndiContext.lookup(destinationName);        } catch (NamingException e) {            LOG.info("JNDI API lookup failed: " + e);            System.exit(1);        }         /*         * Create connection. Create session from connection; false means         * session is not transacted. Create sender and text message. Send         * messages, varying text slightly. Send end-of-messages message.         * Finally, close connection.         */        try {            connection = connectionFactory.createConnection();            session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);            producer = session.createProducer(destination);            TextMessage message = session.createTextMessage();            for (int i = 0; i < numMsgs; i++) {                message.setText("This is message " + (i + 1));                LOG.info("Sending message: " + message.getText());                producer.send(message);            }             /*             * Send a non-text control message indicating end of messages.             */            producer.send(session.createMessage());        } catch (JMSException e) {            LOG.info("Exception occurred: " + e);        } finally {            if (connection != null) {                try {                    connection.close();                } catch (JMSException e) {                }            }        }    }}

Ii. Use spring to use activemq

1. Use spring to configure connectionfactory

<bean id="jmsFactory" class="org.apache.activemq.ActiveMQConnectionFactory">    <property name="brokerURL">      <value>tcp://localhost:61616</value>    </property>  </bean>

Or use zeroconf to query available brokers.

<bean id="jmsFactory" class="org.apache.activemq.ActiveMQConnectionFactory">    <property name="brokerURL">      <value>zeroconf://_activemq.broker.development.</value>    </property>  </bean>

If spring2.0 or later is used, you do not need to explicitly configure the factory Bean

<beans  xmlns="http://www.springframework.org/schema/beans"  xmlns:amq="http://activemq.apache.org/schema/core"  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd  http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/activemq-core.xsd">   <amq:broker useJmx="false" persistent="false">    <amq:transportConnectors>      <amq:transportConnector uri="tcp://localhost:0" />    </amq:transportConnectors>  </amq:broker>   <amq:connectionFactory id="jmsFactory" brokerURL="vm://localhost"/></beans>

2. Configure jmstemplate. The connection pool that comes with activemq is used here.

!-- a pooling based JMS provider -->  <bean id="jmsFactory" class="org.apache.activemq.pool.PooledConnectionFactory" destroy-method="stop">    <property name="connectionFactory">      <bean class="org.apache.activemq.ActiveMQConnectionFactory">        <property name="brokerURL">          <value>tcp://localhost:61616</value>        </property>      </bean>    </property>  </bean>   <!-- Spring JMS Template -->  <bean id="myJmsTemplate" class="org.springframework.jms.core.JmsTemplate">    <property name="connectionFactory">      <ref local="jmsFactory"/>    </property>  </bean>