2014-10-31 06:20:28 -04:00
< html >
< head >
2014-11-19 03:44:57 -05:00
< title > ActiveMQ JMS Topic Example< / title >
2014-10-31 06:20:28 -04:00
< link rel = "stylesheet" type = "text/css" href = "../common/common.css" / >
< link rel = "stylesheet" type = "text/css" href = "../common/prettify.css" / >
< script type = "text/javascript" src = "../common/prettify.js" > < / script >
< / head >
< body onload = "prettyPrint()" >
< h1 > JMS Topic Example< / h1 >
2014-11-19 03:44:57 -05:00
< p > This example shows you how to send and receive a message to a JMS Topic with ActiveMQ.< / p >
2014-10-31 06:20:28 -04:00
< p > Topics are a standard part of JMS, please consult the JMS 1.1 specification for full details.< / p >
< p > A Topic is used to send messages using the publish-subscribe model, from a producer to 1 or more consumers.< / p >
< h2 > Example step-by-step< / h2 >
< p > < i > To run the example, simply type < code > mvn verify< / code > from this directory< / i > < / p >
< ol >
< 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 >
< pre class = "prettyprint" >
< code > InitialContext initialContext = getContext();< / code >
< / pre >
< li > We look-up the JMS topic object from JNDI< / li >
< pre class = "prettyprint" >
< code > Topic topic = (Topic) initialContext.lookup("/topic/exampleTopic");< / code >
< / pre >
< li > We look-up the JMS connection factory object from JNDI< / li >
< pre class = "prettyprint" >
< code > ConnectionFactory cf = (ConnectionFactory) initialContext.lookup("/ConnectionFactory");< / code >
< / pre >
< li > We create a JMS connection< / li >
< pre class = "prettyprint" >
< code > connection = cf.createConnection();< / code >
< / pre >
< li > We create a JMS session. The session is created as non transacted and will auto acknowledge messages.< / li >
< pre class = "prettyprint" >
< code > Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);< / code >
< / pre >
< li > We create a JMS message producer on the session. This will be used to send the messages.< / li >
< pre class = "prettyprint" >
< code > MessageProducer messageProducer = session.createProducer(topic);< / code >
< / pre >
< li > We create a JMS Message Consumer, messageConsumer1, to receive the message.< / li >
< pre class = "prettyprint" >
< code > MessageConsumer messageConsumer = session.createConsumer(topic);< / code >
< / pre >
< li > We create a JMS Message Consumer, messageConsumer2, to also receive the message.< / li >
< pre class = "prettyprint" >
< code > MessageConsumer messageConsumer2 = session.createConsumer(topic);< / code >
< / pre >
< li > We create a JMS text message that we are going to send.< / li >
< pre class = "prettyprint" >
< code > TextMessage message = session.createTextMessage("This is a text message");< / code >
< / pre >
< li > We send message to the topic< / li >
< pre class = "prettyprint" >
< code > messageProducer.send(message);< / code >
< / pre >
< 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 >
< pre class = "prettyprint" >
< code > connection.start();< / code >
< / pre >
< li > The message arrives at the first consumer< / li >
< pre class = "prettyprint" >
< code > TextMessage messageReceived = (TextMessage) messageConsumer1.receive();< / code >
< / pre >
< li > The message arrives at the second consumer< / li >
< pre class = "prettyprint" >
< code > messageReceived = (TextMessage) messageConsumer2.receive();< / code >
< / pre >
< 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 >
< pre class = "prettyprint" >
< code > finally
{
if (initialContext != null)
{
initialContext.close();
}
if (connection != null)
{
connection.close();
}
}< / code >
< / pre >
< / ol >
< / body >
< / html >
