116 lines
5.0 KiB
HTML
116 lines
5.0 KiB
HTML
<html>
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<head>
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<title>ActiveMQ JMS HTTP Transport Example</title>
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<link rel="stylesheet" type="text/css" href="../common/common.css" />
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<link rel="stylesheet" type="text/css" href="../common/prettify.css" />
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<script type="text/javascript" src="../common/prettify.js"></script>
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</head>
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<body onload="prettyPrint()">
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<h1>JMS HTTP Example</h1>
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<p>This example shows you how to configure ActiveMQ to use the HTTP protocol as its transport layer.</p>
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<p>ActiveMQ supports a variety of network protocols to be its underlying transport without any specific code change.</p>
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<p>This example is taken from the queue example without any code change. By changing the configuration file, one can get ActiveMQ working with HTTP transport.</p>
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<p>All you need to do is open the server0/activemq-configuration.xml and enable HTTP like the following</p>
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<pre class="prettyprint">
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<code>
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<connector name="netty-connector">
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<factory-class>org.apache.activemq.core.remoting.impl.netty.NettyConnectorFactory</factory-class>
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<param key="activemq.remoting.netty.http-enabled" value="true" type="Boolean"/>
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<param key="activemq.remoting.netty.port" value="8080" type="Integer"/>
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</connector>
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<!-- Acceptors -->
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<acceptor name="netty-acceptor">
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<factory-class>org.apache.activemq.core.remoting.impl.netty.NettyAcceptorFactory</factory-class>
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<param key="activemq.remoting.netty.port" value="8080" type="Integer"/>
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</acceptor>
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</code>
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</pre>
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<h2>Example step-by-step</h2>
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<p><i>To run the example, simply type <code>mvn verify</code> from this directory</i></p>
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<ol>
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<li>First we need to get an initial context so we can look-up the JMS connection factory and destination objects from JNDI. This initial context will get it's properties from the <code>client-jndi.properties</code> file in the directory <code>../common/config</code></li>
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<pre class="prettyprint">
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<code>InitialContext initialContext = getContext();</code>
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</pre>
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<li>We look-up the JMS queue object from JNDI</li>
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<pre class="prettyprint">
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<code>Queue queue = (Queue) initialContext.lookup("/queue/exampleQueue");</code>
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</pre>
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<li>We look-up the JMS connection factory object from JNDI</li>
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<pre class="prettyprint">
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<code>ConnectionFactory cf = (ConnectionFactory) initialContext.lookup("/ConnectionFactory");</code>
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</pre>
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<li>We create a JMS connection</li>
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<pre class="prettyprint">
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<code>connection = cf.createConnection();</code>
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</pre>
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<li>We create a JMS session. The session is created as non transacted and will auto acknowledge messages.</li>
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<pre class="prettyprint">
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<code>Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);</code>
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</pre>
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<li>We create a JMS message producer on the session. This will be used to send the messages.</li>
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<pre class="prettyprint">
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<code>MessageProducer messageProducer = session.createProducer(topic);</code>
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</pre>
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<li>We create a JMS text message that we are going to send.</li>
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<pre class="prettyprint">
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<code>TextMessage message = session.createTextMessage("This is a text message");</code>
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</pre>
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<li>We send message to the queue</li>
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<pre class="prettyprint">
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<code>messageProducer.send(message);</code>
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</pre>
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<li>We create a JMS Message Consumer to receive the message.</li>
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<pre class="prettyprint">
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<code>MessageConsumer messageConsumer = session.createConsumer(queue);</code>
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</pre>
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<li>We start the connection. In order for delivery to occur on any consumers or subscribers on a connection, the connection must be started</li>
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<pre class="prettyprint">
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<code>connection.start();</code>
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</pre>
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<li>The message arrives at the consumer. In this case we use a timeout of 5000 milliseconds but we could use a blocking 'receive()'</li>
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<pre class="prettyprint">
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<code>TextMessage messageReceived = (TextMessage) messageConsumer.receive(5000);</code>
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</pre>
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<li>And finally, <b>always</b> remember to close your JMS connections and resources after use, in a <code>finally</code> block. Closing a JMS connection will automatically close all of its sessions, consumers, producer and browser objects</li>
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<pre class="prettyprint">
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<code>finally
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{
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if (initialContext != null)
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{
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initialContext.close();
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}
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if (connection != null)
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{
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connection.close();
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}
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}</code>
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</pre>
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</ol>
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</body>
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</html>
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