?在下面的例子中，分別發送一個Persistent和nonpersistent的消息，然后關閉退出JMS。

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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!");??

????}??

}??

?
??? 運行上面的程序，當輸出“Send messages sucessfully!”時，說明兩個消息都已經發送成功，然后我們結束它，來停止JMS Provider。

??? 接下來我們重新啟動JMS Provicer，然后添加一個消費者：

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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();??

????????????????}??

????????????}??

????????});??

????}??

}??

運行上面的程序，可以得到下面的輸出結果：

Consumer get A persistent Message

可以看出消息消費者只接收到一個消息，它是一個Persistent的消息。而剛才發送的non persistent消息已經丟失了。

另外, 如果發送一個non persistent消息, 而剛好這個時候沒有消費者在監聽, 這個消息也會丟失.

總結

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