WildFly JavaEE - 在运行时启动/停止消息驱动 Bean

Question

我有一个关于消息驱动 Bean (MDB) 的问题。有没有办法只在运行时生成这些？我想在我的后端提供一种方法来开始或停止接收消息。它应该通过数据库中的配置条目进行控制。在启动 WildFly 时，还应首先检查 MDB 是否可以启动。

在没有 MDB 的情况下手动创建侦听器是否符合 Java EE？

我目前正在使用以下代码

@MessageDriven(name = "MyMDB", activationConfig = {
        @ActivationConfigProperty(propertyName = "maxSession", propertyValue = "2"),
        @ActivationConfigProperty(propertyName = "destination", propertyValue = "java:/jms/queue/Test"),
        @ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue"),
        @ActivationConfigProperty(propertyName = "acknowledgeMode", propertyValue = "Auto-acknowledge")})
public class JmsConsumer implements MessageListener {

    @Override
    public void onMessage(final Message msg) {

        if (msg instanceof TextMessage) {
            try {
                final String text = ((TextMessage) msg).getText();

                System.out.println("message: " + text + " (" + msg.getJMSRedelivered() + ")");

            } catch (final JMSException e) {
                e.printStackTrace();
            }
        }
    }
}

此代码是否也符合 Java EE？

@Singleton
@LocalBean
public class QueueWorkerManager {
    private InitialContext initialContext = null;
    private QueueConnectionFactory queueConnectionFactory = null;
    private Queue queue = null;
    private QueueConnection queueConnection = null;
    private QueueSession queueSession = null;
    private MessageConsumer consumer = null;

    @PostConstruct
    public void init() {
        try {
            this.initialContext = new InitialContext();
            this.queueConnectionFactory = (QueueConnectionFactory) initialContext
                    .lookup("java:/ConnectionFactory");

            this.queue = (Queue) initialContext.lookup(MyQueueSender.WORKER_QUEUE);
            this.queueConnection = queueConnectionFactory.createQueueConnection();
            this.queueSession = queueConnection.createQueueSession(false, Session.CLIENT_ACKNOWLEDGE);

            this.consumer = queueSession.createConsumer(this.queue);
            this.consumer.setMessageListener(new ConsumerMessageListener());

            this.queueConnection.start();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    @PreDestroy
    public void destroy() {
        this.stopConsumer(this.consumer;
        if(this.consumer != null) {
            try {
                this.consumer.close();
            } catch (JMSException e) {
            }
            this.consumer = null;
        }

        if(this.queueSession != null) {
            try {
                this.queueSession.close();
            } catch (JMSException e) {
            }
            this.queueSession = null;
        }

        if(this.queueConnection != null) {
            try {
                this.queueConnection.close();
            } catch (JMSException e) {
            }
            this.queueConnection = null;
        }
    }
}

public class ConsumerMessageListener implements MessageListener {

    @Override
    public void onMessage(Message message) {
        TextMessage textMessage = (TextMessage) message;
        try {
             System.out.println("message: " + textMessage.getText() + " (" + msg.getJMSRedelivered() + ")");
            message.acknowledge();
        } catch (JMSException | InterruptedException e) {          
            e.printStackTrace();
        }
    }

}

Answer 1

我建议你去

• 向您的 MDB 添加 @DeliveryActive(false/true) 注释，以便在所需的初始状态下启动它
• 使用 JMX 或 JBoss CLI 以编程方式更改 MDB 的 active 属性的值

这里解释了一切： https://docs.wildfly.org/16/Developer_Guide.html#Message_Driven_Beans_Controlled_Delivery

祝你好运