深入掌握JMS（八）：JMSReplyTo

在下面的例子中，首先建立兩個Queue，寄件者給一個Queue發送，接收者接收到訊息之後給另一個Queue回複一個Message，然後再建立一個消費者來接受所回複的訊息。

            import javax.jms.Connection;
            import javax.jms.JMSException;
            import javax.jms.Message;
            import javax.jms.MessageConsumer;
            import javax.jms.MessageListener;
            import javax.jms.MessageProducer;
            import javax.jms.Queue;
            import javax.jms.Session;
            import javax.jms.TextMessage;

            import org.apache.activemq.ActiveMQConnectionFactory;
            import org.apache.activemq.command.ActiveMQQueue;

            public class MessageSendReceiveAndReply {

                public static void main(String[] args) throws Exception {
                    ActiveMQConnectionFactory factory = new
            ActiveMQConnectionFactory("vm://localhost");
                    Connection connection = factory.createConnection();
                    connection.start();
                    //訊息發送到這個Queue
                    Queue queue = new ActiveMQQueue("testQueue");

                    //訊息回複到這個Queue
                    Queue replyQueue = new ActiveMQQueue("replyQueue");
                    final Session session = connection.createSession(false,
            Session.AUTO_ACKNOWLEDGE);

                    //建立一個訊息，並設定它的JMSReplyTo為replyQueue。
                    Message message = session.createTextMessage("Andy");
                    message.setJMSReplyTo(replyQueue);
                    MessageProducer producer = session.createProducer(queue);
                    producer.send(message);
                    //訊息的接收者
                    MessageConsumer comsumer = session.createConsumer(queue);
                    comsumer.setMessageListener(new MessageListener(){
                        public void onMessage(Message m) {
                            try {
                                //建立一個新的MessageProducer來發送一個回複訊息。
                                MessageProducer producer =
            session.createProducer(m.getJMSReplyTo());
                                producer.send(session.createTextMessage("Hello "
            + ((TextMessage) m).getText()));
                            } catch (JMSException e1) {
                                e1.printStackTrace();
                            }
                        }
                    });
                    //這個接收者用來接收回複的訊息
                    MessageConsumer comsumer2 =
            session.createConsumer(replyQueue);
                    comsumer2.setMessageListener(new MessageListener(){
                        public void onMessage(Message m) {
                            try {
                                System.out.println(((TextMessage) m).getText());
                            } catch (JMSException e) {
                                e.printStackTrace();
                            }
                        }
                    });
                }

            }

                首先訊息生產者發送一個訊息，內容為“Andy”，
            然後消費者收到這個訊息之後根據訊息的JMSReplyTo，回複一個訊息，內容為“Hello Andy'。
            最後在回複的Queue上建立一個接收回複訊息的消費者，它輸出所回複的內容。

                運行上面的程式，可以得到下面的輸出結果：

            Hello Andy