ActiveMQ embedded broker topic-to-queue bridge wit

2019-08-08 13:12发布

问题:

My Goal + Progress

I'm interested in using ActiveMQ to publish a message to a topic and have it bridge to multiple queues. I have managed to achieve this with the command-line broker by providing an xml-config containing a composite topic:

<destinationInterceptors>
    <virtualDestinationInterceptor>
        <virtualDestinations>
            <compositeTopic name="LOCAL.EC.T">
                <forwardTo>
                    <queue physicalName="LOCAL.EC.Q.1" />
                    <queue physicalName="LOCAL.EC.Q.2" />                       
                </forwardTo>
            </compositeTopic>
        </virtualDestinations>
    </virtualDestinationInterceptor>
</destinationInterceptors>

Using this start-up command: activemq start xbean:amq.xml. In this case, amq.xml is my active MQ XML configuration file. There is more on xml configuration here: http://activemq.apache.org/xml-configuration.html.

My Problem

If I publish a message to the topic above using the web console, it shows up in both queues as expected. But now I want to switch to using an embedded broker.


In the following code, I can tell that it is using my amq.xml file (as when I change it I get relevant errors), but when I publish to the topic, the receive on the queue blocks forever. If I publish and receive to the same topic or queue though, everything works fine. Why is my composite topic not working here?


//Create the broker using the xbean configuration and start it.
brokerService = BrokerFactory.createBroker(new URI("xbean:amq.xml"));
brokerService.setBrokerName("localhost");
brokerService.setPersistent(false);
brokerService.setDeleteAllMessagesOnStartup(true);
brokerService.setUseJmx(false);
brokerService.start();

//Create the connection factory and JMS template.
connectionFactory = new ActiveMQConnectionFactory();
connectionFactory.setBrokerURL("vm://localhost?create=false&jms.redeliveryPolicy.maximumRedeliveries=-1");

//Send the message to the topic.
template = new JmsTemplate(connectionFactory);
ActiveMQMapMessage message = new ActiveMQMapMessage();
message.setString("batch", "Hello World!");
template.convertAndSend("LOCAL.EC.T",message);

//Read the message from the queues.
final Message receive = template.receive("LOCAL.EC.Q.1");
MapMessage received = (MapMessage)receive;
System.out.println(received.getString("batch"));  

回答1:

I found an example on a website which demonstrated how to produce a message in a slightly different way. Unfortunately, I closed the tab and can't find the link to reference it.

Either way, I combined that message-production style with my xbean configuration and now everything is working. Here's the working code:

brokerService = BrokerFactory.createBroker(new URI("xbean:amq.xml"));
brokerService.setPersistent(false);
brokerService.setDeleteAllMessagesOnStartup(true);
brokerService.setUseJmx(false);
brokerService.start();

connectionFactory = new ActiveMQConnectionFactory("vm://localhost");
template = new JmsTemplate(connectionFactory);

//Create a connection.
Connection connection = connectionFactory.createConnection();
connection.start();

//Create a session.
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);

//Create a topic and publish to it - it should be linked to 4 queues by the configuration.
System.out.println("Posting message to topic:");
Destination destination = session.createTopic("LOCAL.EC.T");
MessageProducer producer = session.createProducer(destination);
producer.setDeliveryMode(DeliveryMode.PERSISTENT);
ActiveMQMapMessage message = new ActiveMQMapMessage();
message.setString("batch", "Hello World!");
producer.send(message);

//Read the message from the queues.
System.out.println("Q1: " + ((MapMessage)receive("LOCAL.EC.Q.1")).getString("batch"));
System.out.println("Q2: " + ((MapMessage)receive("LOCAL.EC.Q.2")).getString("batch"));
System.out.println("Q3: " + ((MapMessage)receive("LOCAL.EC.Q.3")).getString("batch"));
System.out.println("Q4: " + ((MapMessage)receive("LOCAL.EC.Q.4")).getString("batch"));

Output:

Posting message to topic:

Q1: Hello World!

Q2: Hello World!

Q3: Hello World!

Q4: Hello World!

Ending application.

Hopefully it helps someone else out!