ejb3学习札记5

ejb3学习笔记5

开发消息驱动bean

1定义消息驱动bean 服务

定义queue 和topic 消息驱动bean。

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1. <?xml?version="1.0"?encoding="UTF-8"?>??<server>??
2. ????<mbean?code="org.jboss.mq.server.jmx.Queue"?? ?????????????????name="jboss.mq.destination:service=Queue,name=itcastQueue">??
3. ?????<attribute?name="JNDIName">queue/itcastQueue</attribute>?? ?????<depends?optional-attribute-name="DestinationManager">jboss.mq:service=DestinationManager</depends>??
4. ??</mbean>????<mbean?code="org.jboss.mq.server.jmx.Topic"??
5. ?????????????????name="jboss.mq.destination:service=Topic,name=itcastTopic">?? ?????<attribute?name="JNDIName">topic/itcastTopic</attribute>??
6. ?????<depends?optional-attribute-name="DestinationManager">jboss.mq:service=DestinationManager</depends>?? ??</mbean>??
7. </server>??

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2 向bean 发送消息

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1. InitialContext?ctx?=?new?InitialContext();??QueueConnectionFactory?factory?=?(QueueConnectionFactory)ctx.lookup("QueueConnectionFactory");??
2. QueueConnection?conn?=?factory.createQueueConnection();??QueueSession?session?=?conn.createQueueSession(false,?QueueSession.AUTO_ACKNOWLEDGE);//事物?消息确认模式? ??
3. Destination?destination?=?(Destination)ctx.lookup("queue/itcastQueue");?? MessageProducer?producer?=?session.createProducer(destination);??
4. producer.send(session.createTextMessage("你好"));?? session.close();??
5. conn.close();??

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topic消息 只需要将Queue改成Topic 即可

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3 从bean中接受消息

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1. @MessageDriven(activationConfig={??????@ActivationConfigProperty(propertyName="destinationType",?propertyValue="javax.jms.Queue"),??
2. ????@ActivationConfigProperty(propertyName="destination",?propertyValue="queue/itcastQueue")?????????? })??
3. public?class?MessageDrivenBean?implements?MessageListener{?? ??
4. ????public?void?onMessage(Message?message)?{?? ????????try?{??
5. ????????????TextMessage?msg?=?(TextMessage)message;??????????????System.out.println(msg.getText());??
6. ????????}?catch?(JMSException?e)?{?? ????????????e.printStackTrace();??
7. ????????}??????}??
8. }??

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4 消息：

消息，由消息头和消息正文组成

JMS的异步性：JMS生产者发送消息后，无需阻塞进程，不需要管谁是消费者。

JMS消息传递模型：JMS Provider提供两种消息传递模型，及发布-订阅模型（Pub/Sub）和点对点模型（PtP）。

StreamMessage

MapMessage

TextMessage

ObjectMessage

BytesMessage