【转】DeliveryMode例子
在下面的例子中，分别发送一个Persistent和nonpersistent的消息，然后关闭退出JMS。
??????????? import javax.jms.Connection;
??????????? import javax.jms.DeliveryMode;
??????????? import javax.jms.MessageProducer;
??????????? import javax.jms.Queue;
??????????? import javax.jms.Session;
??????????? import org.apache.activemq.ActiveMQConnectionFactory;
??????????? import org.apache.activemq.command.ActiveMQQueue;
??????????? public class DeliveryModeSendTest {
??????????????? public static void main(String[] args) throws Exception {
??????????????????? ActiveMQConnectionFactory factory = new
??????????? ActiveMQConnectionFactory("vm://localhost");
??????????????????? Connection connection = factory.createConnection();
??????????????????? connection.start();
??????????????????? Queue queue = new ActiveMQQueue("testQueue");
??????????????????? Session session = connection.createSession(false,
??????????? Session.AUTO_ACKNOWLEDGE);
??????????????????? MessageProducer producer = session.createProducer(queue);
??????????????????? producer.setDeliveryMode(DeliveryMode.PERSISTENT);
??????????????????? producer.send(session.createTextMessage("A persistent
??????????? Message"));
??????????????????? producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
??????????????????? producer.send(session.createTextMessage("A non persistent
??????????? Message"));
??????????????????? System.out.println("Send messages sucessfully!");
??????????????? }
??????????? }
??????????????? 运行上面的程序，当输出“Send messages
??????????? sucessfully!”时，说明两个消息都已经发送成功，然后我们结束它，来停止JMS Provider。
??????????????? 接下来我们重新启动JMS Provicer，然后添加一个消费者：
??????????? import javax.jms.Connection;
??????????? import javax.jms.JMSException;
??????????? import javax.jms.Message;
??????????? import javax.jms.MessageConsumer;
??????????? import javax.jms.MessageListener;
??????????? 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 DeliveryModeReceiveTest {
??????????????? public static void main(String[] args) throws Exception {
??????????????????? ActiveMQConnectionFactory factory = new
??????????? ActiveMQConnectionFactory("vm://localhost");
??????????????????? Connection connection = factory.createConnection();
??????????????????? connection.start();
??????????????????? Queue queue = new ActiveMQQueue("testQueue");
??????????????????? Session session = connection.createSession(false,
??????????? Session.AUTO_ACKNOWLEDGE);
??????????????????? MessageConsumer comsumer = session.createConsumer(queue);
??????????????????? comsumer.setMessageListener(new MessageListener(){
??????????????????????? public void onMessage(Message m) {
??????????????????????????? try {
??????????????????????????????? System.out.println("Consumer get " +
??????????? ((TextMessage)m).getText());
??????????????????????????? } catch (JMSException e) {
??????????????????????????????? e.printStackTrace();
??????????????????????????? }
??????????????????????? }
??????????????????? });
??????????????? }
??????????? }
??????????? 运行上面的程序，可以得到下面的输出结果：
??????????? Consumer get A persistent Message
??????????? 可以看出消息消费者只接收到一个消息，它是一个Persistent的消息。而刚才发送的non persistent消息已经丢失了。
??????????? 另外, 如果发送一个non persistent消息, 而刚好这个时候没有消费者在监听, 这个消息也会丢失.
