ActiveMQ - 虚拟topics

当我们需要广播的时候，我们采用发布订阅模式。生产者往broker发送1，2，3，4，5，6，消费者1和消费者2都收到1，2，3，4，5，6。

activemq提供了一个虚拟topics的功能，首先元素的开头必须是VirtualTopic.开头的，消费端的格式是Consumer..VirtualTopic.. ，比如生产者的是VirtualTopic.topic，那消费者A是Consumer.a.VirtualTopic.topic，a表示消费端组的名称，名字一样的话，会类似ptp一样消费。

示例

生产者主要代码是：

Topic destination = session.createTopic("VirtualTopic.topic");

生产者这边发送6个数据：

public static void main(String[] args) {
    ConnectionFactory connectionFactory;
    Connection connection = null;
    Session session = null;
    MessageProducer producer = null;
    boolean useTransaction = false;
    try {
        // 创建一个ConnectionFactory
        connectionFactory = new ActiveMQConnectionFactory();
        // 创建一个Connection
        connection = connectionFactory.createConnection();
        // 启动消息传递的连接
        connection.start();
        // 创建一个session
        session = connection.createSession(useTransaction, Session.AUTO_ACKNOWLEDGE);
        // 创建一个destination，把消息发送到test.queue
        Topic destination = session.createTopic("VirtualTopic.topic");
        // 创建一个生产者
        producer = session.createProducer(destination);
        // 创建一个消息
        for (int i = 0; i < 6; i++) {
            // 创建一个消息
            Message message = session.createTextMessage("this is VirtualTopic:" + i);
            // 发送消息
            producer.send(message);
        }
    } catch (JMSException e) {
        e.printStackTrace();
    } finally {
        try {
            if (producer != null) {
                producer.close();
            }
            if (session != null) {
                session.close();
            }
            if (connection != null) {
                connection.close();
            }
        } catch (JMSException e) {
            e.printStackTrace();
        }
    }
}

消费者a-1和消费者a-2，同时消费数据，这边仅贴消费者a-1的代码

public static void main(String[] args) {
    ConnectionFactory connectionFactory;
    Connection connection = null;
    Session session = null;
    Destination destination;
    MessageConsumer consumer = null;
    Message message;
    boolean useTransaction = false;
    try {
        // 创建一个ConnectionFactory
        connectionFactory = new ActiveMQConnectionFactory();
        // 创建一个Connection
        connection = connectionFactory.createConnection();
        // 启动消息传递的连接
        connection.start();
        // 创建一个session
        session = connection.createSession(useTransaction, Session.AUTO_ACKNOWLEDGE);
        // 创建一个destination，把消息发送到test.queue
        destination = session.createQueue("Consumer.a.VirtualTopic.topic");
        // 创建一个消费者
        consumer = session.createConsumer(destination);
        // 接收一个消息
        while (null != (message = consumer.receive())) {
            System.out.println("consumer-a-1 receive:" + ((TextMessage) message).getText());
        }
    } catch (JMSException e) {
        e.printStackTrace();
    } finally {
        try {
            if (consumer != null) {
                consumer.close();
            }
            if (session != null) {
                session.close();
            }
            if (connection != null) {
                connection.close();
            }
        } catch (JMSException e) {
            e.printStackTrace();
        }
    }
}

消费者b自己消费消息：

public static void main(String[] args) {
    ConnectionFactory connectionFactory;
    Connection connection = null;
    Session session = null;
    Destination destination;
    MessageConsumer consumer = null;
    Message message;
    boolean useTransaction = false;
    try {
        // 创建一个ConnectionFactory
        connectionFactory = new ActiveMQConnectionFactory();
        // 创建一个Connection
        connection = connectionFactory.createConnection();
        // 启动消息传递的连接
        connection.start();
        // 创建一个session
        session = connection.createSession(useTransaction, Session.AUTO_ACKNOWLEDGE);
        // 创建一个destination，把消息发送到test.queue
        destination = session.createQueue("Consumer.b.VirtualTopic.topic");
        // 创建一个消费者
        consumer = session.createConsumer(destination);
        // 接收一个消息
        while (null != (message = consumer.receive())) {
            System.out.println("consumer-b-2 receive:" + ((TextMessage) message).getText());
        }
    } catch (JMSException e) {
        e.printStackTrace();
    } finally {
        try {
            if (consumer != null) {
                consumer.close();
            }
            if (session != null) {
                session.close();
            }
            if (connection != null) {
                connection.close();
            }
        } catch (JMSException e) {
            e.printStackTrace();
        }
    }
}

运行结果如下：
消费者a-1消费了024