JMS入门——开发起步之ActiveMQ

J2EE与JMS

JMS是J2EE的13种核心技术规范之一，是J2EE众多应用程序组件中的重要一员。J2EE有标准的JMS API开放，以支持各个JMS应用生产厂商的产品,开源的有jbossmq，openjms，mantamq，ActiveMQ等，不过大多已停止发展; 商业的有IBM WebSphere MQ, BEA WebLogic JMS, Oracle AQ等。

它功能强大,支持多种语言编写的客户端,符合J2EE1.4规范,支持持久化,甚至支持Ajax等等.

JMS开发入门

环境: jdk1.5以上, eclipse for j2ee版本, ${download}/activemq5.4.2/bin/activemq.exe运行起来

jar包: activemq-all-5.4.2.jar(官方发布里有)   commons-logging-1.1.jar 

废话不多说, 上代码先, demo1代码：

/*
 * xcch@cnic.cn
 * 消息发送者
 */
import java.util.Date;
import javax.jms.*;
import org.apache.activemq.ActiveMQConnectionFactory;

public class MessageSender {

     public static void main(String[] args) throws Exception {
         //ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("failover:(tcp://primary:61616)?timeout=3000&startupMaxReconnectAttempts=1&maxReconnectAttempts=0");//failover:失效转移
         ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://primary:61616?connectionTimeout=3000");

         Connection connection = connectionFactory.createConnection();
         //connection.setExceptionListener(new MyJmsException());
         connection.start();

         Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
         Destination destination = session.createQueue("my-queue");

         MessageProducer producer = session.createProducer(destination);
         for(int i=0; i<3; i++) {
             MapMessage message = session.createMapMessage();
             message.setLong("count", new Date().getTime());
             Thread.sleep(1000);
             //通过消息生产者发出消息
             producer.send(message);
         }
         session.commit();
         session.close();
         connection.close();
    } 
}
 

/*
 * 消息接收者
 */
import java.util.Date;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.MapMessage;
import javax.jms.MessageConsumer;
import javax.jms.Session;

import org.apache.activemq.ActiveMQConnectionFactory;

public class MessageReceiver {
    public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ActiveMQConnectionFactory();

        Connection connection = connectionFactory.createConnection();
        connection.start();

        final Session session = connection.createSession(Boolean.TRUE,
                Session.AUTO_ACKNOWLEDGE);
        Destination destination = session.createQueue("my-queue");

        MessageConsumer consumer = session.createConsumer(destination);

        int i = 0;
        while (i < 3) {
            i++;
            MapMessage message = (MapMessage) consumer.receive();
            session.commit();

            // TODO something....
            System.out.println("收到消息：" + new Date(message.getLong("count")));
        }

        session.close();
        connection.close();
    }
} 

注意,这里要求先将activemq.exe运行起来,作为JMS的Provider.其实J2EE官方发行版里面应该也带有JMS的一个Provider,相关的demo参考2

字符串 "tcp://primary:61616?connectionTimeout=3000" 表示一个URI,它包括了协议部分,url部分,及选项. ActiveMQ其实支持多种transport(参考2),不同的transport对应不同的URI(格式,选项参数等不同).

参考：

1. Oracle-JMS部分参考/javaee/1.3/jms/tutorial/1_3_1-fcs/doc/client.html
2. J2EE-JMS部分参考：/javaee/6/tutorial/doc/bncdr.html
3. JMS常见transport参考:/blog/164933