EJB之讯息驱动bean

EJB之消息驱动bean
java消息服务(简称JMS)是用于访问企业消息系统的开发商的API，可以概括为应用程序A发送一条消息到消息服务器的某个目的地，然后消息服务器将消息发送给监听这个目的地的程序B，JMS支持两种消息传递模型，点对点(简称PTP)和发布/订阅(简称pub/sub)，PTP规定一条消息只能发送给一个接收方，pub/sub允许一条消息发送给多个接收方，以下是个JMS的小例子
1.首先我们需要配置消息到达的目的地址，命名规范为*-service.xml,每个应用服务器的配置都不同，我用的是JBoss，代码如下

<?xml version="1.0" encoding="UTF-8"?> <server>  <mbean code="org.jboss.mq.server.jmx.Queue" name="jboss.mq.destination:service=Queue,name=liaokangQueue"> <attribute name="JNDIName">queue/liaokangQueue</attribute> <depends optional-attribute-name="DestinationManager">jboss.mq:service=DestinationManager</depends>    </mbean>   <mbean code="org.jboss.mq.server.jmx.Topic" name="jboss.mq.destination:service=Topic,name=liaokangTopic"> <attribute name="JNDIName">topic/liaokangTopic</attribute> <depends optional-attribute-name="DestinationManager">jboss.mq:service=DestinationManager</depends>    </mbean> </server>

将其部署在server\default\deploy目录下

2.新建一个java项目，并将jboss的client目录下的jar文件全部引入，新建一个类来向目的地发送消息，代码如下，这是Queue消息

package com.lamp.app;import javax.jms.Destination;import javax.jms.JMSException;import javax.jms.MessageProducer;import javax.jms.QueueConnection;import javax.jms.QueueConnectionFactory;import javax.jms.QueueSession;import javax.naming.InitialContext;import javax.naming.NamingException;public class QueueSender {public static void main(String[] args) {try {InitialContext ctx = new InitialContext();QueueConnectionFactory factory = (QueueConnectionFactory)ctx.lookup("QueueConnectionFactory");QueueConnection conn = factory.createQueueConnection();QueueSession session = conn.createQueueSession(false, QueueSession.AUTO_ACKNOWLEDGE);Destination destination = (Destination) ctx.lookup("queue/liaokangQueue");MessageProducer producer = session.createProducer(destination);producer.send(session.createTextMessage("欢迎来到消息驱动的世界,这是queue消息"));session.close();conn.close();} catch (NamingException e) {e.printStackTrace();} catch (JMSException e) {e.printStackTrace();}}}

当然不要忘记在src目录下新建JNDI的配置文件jndi.properties
java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory
java.naming.provider.url=localhost:1099

然后采用消息驱动bean来接受消息

package com.lamp.message;import javax.ejb.ActivationConfigProperty;import javax.ejb.MessageDriven;import javax.jms.JMSException;import javax.jms.Message;import javax.jms.MessageListener;import javax.jms.TextMessage;@MessageDriven(activationConfig={@ActivationConfigProperty(propertyName="destinationType",propertyValue="javax.jms.Queue"),@ActivationConfigProperty(propertyName="destination",propertyValue="queue/liaokangQueue")})public class MessageDriverBean implements MessageListener{public void onMessage(Message message) {TextMessage tmsg = (TextMessage)message;try {System.out.println(tmsg.getText());} catch (JMSException e) {e.printStackTrace();}}}

以下是Topic消息的发送
Topic消息发送类

package com.lamp.app;import javax.jms.Destination;import javax.jms.JMSException;import javax.jms.MessageProducer;import javax.jms.TopicConnection;import javax.jms.TopicConnectionFactory;import javax.jms.TopicSession;import javax.naming.InitialContext;import javax.naming.NamingException;public class TopicSender {public static void main(String[] args) {try {InitialContext ctx = new InitialContext();TopicConnectionFactory factory = (TopicConnectionFactory) ctx.lookup("TopicConnectionFactory");TopicConnection conn = factory.createTopicConnection();TopicSession session = conn.createTopicSession(false,TopicSession.AUTO_ACKNOWLEDGE);Destination destination = (Destination) ctx.lookup("topic/liaokangTopic");MessageProducer producer = session.createProducer(destination);producer.send(session.createTextMessage("欢迎来到消息驱动的世界,这是topic消息"));session.close();conn.close();} catch (NamingException e) {e.printStackTrace();} catch (JMSException e) {e.printStackTrace();}}}

topic消息类型接收类

package com.lamp.message;import javax.ejb.ActivationConfigProperty;import javax.ejb.MessageDriven;import javax.jms.JMSException;import javax.jms.Message;import javax.jms.MessageListener;import javax.jms.TextMessage;@MessageDriven(activationConfig={@ActivationConfigProperty(propertyName="destinationType",propertyValue="javax.jms.Topic"),@ActivationConfigProperty(propertyName="destination",propertyValue="topic/liaokangTopic")})public class TopicReceiver implements MessageListener {public void onMessage(Message message) {TextMessage tmsg = (TextMessage)message;try {System.out.println(tmsg.getText());} catch (JMSException e) {e.printStackTrace();}}}

不同Queue的是你可以新建多个消息接受类来接受同一个目的地Topic类型的消息
最后将工程打包成jar，部署到JBossserver\default\deploy目录下，在发送方类中运行main方法


   

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