ActiveMQ学习教程（一）——安装与示例

原文转自：http://shhyuhan.iteye.com/blog/1278103

背景：ActiveMQ 是Apache出品，最流行的，能力强劲的开源消息总线。 
选择ActiveMQ作为JMS的入门学习中间件，是因为其拥有以下优点 

1.多种语言和协议编写客户端。语言: Java, C, C++, C#, Ruby, Perl, Python, PHP。应用协议: OpenWire,Stomp REST,WS Notification,XMPP,AMQP 
2.完全支持JMS1.1和J2EE 1.4规范 (持久化,XA消息,事务) 
3.对Spring的支持,ActiveMQ可以很容易内嵌到使用Spring的系统里面去,而且也支持Spring2.0的特性 
4.完全支持JMS1.1和J2EE 1.4规范 (持久化,XA消息,事务) 
5.通过了常见J2EE服务器(如 Geronimo,JBoss 4, GlassFish,WebLogic)的测试,其中通过JCA 1.5 resource adaptors的配置,可以让ActiveMQ可以自动的部署到任何兼容J2EE 1.4 商业服务器上 
6.支持多种传送协议:in-VM,TCP,SSL,NIO,UDP,JGroups,JXTA 
7.从设计上保证了高性能的集群,客户端-服务器,点对点 
8.支持Ajax 
9.支持与Axis的整合 
10.可以很容易得调用内嵌JMS provider,进行测试 

学会了ActiveMQ之后，其它供应商的MQ也可以在短时间内快速上手。 

安装： 
ActiveMQ（本文简称MQ）要求JDK1.5以上，推荐1.6以上版本。还没安装JDK的朋友，请先安装，在此不赘诉了。 
安装完JDK后，从  http://activemq.apache.org/download.html 下载MQ的最新版本，本教程使用版本为5.5。 
解压后，可以看到MQ目录下有以下文件和目录 

activemq-all-5.5.0.jar:所有MQ JAR包的集合，用于用户系统调用 
bin:其中包含MQ的启动脚本 
conf:包含MQ的所有配置文件 
data:日志文件及持久性消息数据 
example:MQ的示例 
lib:MQ运行所需的所有Lib 
webapps:MQ的Web控制台及一些相关的DEMO 

启动MQ： 
双击bin目录下的activemq.bat文件即可启动MQ 


第一个示例： 

新建一个JAVA工程，引用activemq-all-5.5.0.jar，SLFAPI其及对应版本LOG4J的JAR包（懒的上网找的到附件里下载） 

Publisher.java 

 import java.util.Hashtable;
 import java.util.Map;

 import javax.jms.Connection;
 import javax.jms.ConnectionFactory;
 import javax.jms.Destination;
 import javax.jms.JMSException;
 import javax.jms.MapMessage;
 import javax.jms.Message;
 import javax.jms.MessageProducer;
 import javax.jms.Session;

 import org.apache.activemq.ActiveMQConnectionFactory;
 import org.apache.activemq.command.ActiveMQMapMessage;

 public class Publisher {

     protected int MAX_DELTA_PERCENT = 1;
     protected Map<String, Double> LAST_PRICES = new Hashtable<String, Double>();
     protected static int count = 10;
     protected static int total;

     protected static String brokerURL = "tcp://localhost:61616";
     protected static transient ConnectionFactory factory;
     protected transient Connection connection;
     protected transient Session session;
     protected transient MessageProducer producer;

     public Publisher() throws JMSException {
         factory = new ActiveMQConnectionFactory(brokerURL);
         connection = factory.createConnection();
         try {
         connection.start();
         } catch (JMSException jmse) {
             connection.close();
             throw jmse;
         }
         session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
         producer = session.createProducer(null);
     }

     public void close() throws JMSException {
         if (connection != null) {
             connection.close();
         }
     }

     public static void main(String[] args) throws JMSException {
         Publisher publisher = new Publisher();
         while (total < 1000) {
             for (int i = 0; i < count; i++) {
                 publisher.sendMessage(args);
             }
             total += count;
             System.out.println("Published '" + count + "' of '" + total + "' price messages");
             try {
               Thread.sleep(1000);
             } catch (InterruptedException x) {
             }
         }
         publisher.close();
     }

     protected void sendMessage(String[] stocks) throws JMSException {
         int idx = 0;
         while (true) {
             idx = (int)Math.round(stocks.length * Math.random());
             if (idx < stocks.length) {
                 break;
             }
         }
         String stock = stocks[idx];
         Destination destination = session.createTopic("STOCKS." + stock);
         Message message = createStockMessage(stock, session);
         System.out.println("Sending: " + ((ActiveMQMapMessage)message).getContentMap() + " on destination: " + destination);
         producer.send(destination, message);
     }

     protected Message createStockMessage(String stock, Session session) throws JMSException {
         Double value = LAST_PRICES.get(stock);
         if (value == null) {
             value = new Double(Math.random() * 100);
         }

         // lets mutate the value by some percentage
         double oldPrice = value.doubleValue();
         value = new Double(mutatePrice(oldPrice));
         LAST_PRICES.put(stock, value);
         double price = value.doubleValue();

         double offer = price * 1.001;

         boolean up = (price > oldPrice);

         MapMessage message = session.createMapMessage();
         message.setString("stock", stock);
         message.setDouble("price", price);
         message.setDouble("offer", offer);
         message.setBoolean("up", up);
         return message;
     }

     protected double mutatePrice(double price) {
         double percentChange = (2 * Math.random() * MAX_DELTA_PERCENT) - MAX_DELTA_PERCENT;

         return price * (100 + percentChange) / 100;
     }

 }

Consumer.java 

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

 import org.apache.activemq.ActiveMQConnectionFactory;

 public class Consumer {

     private static String brokerURL = "tcp://localhost:61616";
     private static transient ConnectionFactory factory;
     private transient Connection connection;
     private transient Session session;

     public Consumer() throws JMSException {
         factory = new ActiveMQConnectionFactory(brokerURL);
         connection = factory.createConnection();
         connection.start();
         session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
     }

     public void close() throws JMSException {
         if (connection != null) {
             connection.close();
         }
     }

     public static void main(String[] args) throws JMSException {
         Consumer consumer = new Consumer();
         for (String stock : args) {
             Destination destination = consumer.getSession().createTopic("STOCKS." + stock);
             MessageConsumer messageConsumer = consumer.getSession().createConsumer(destination);
             messageConsumer.setMessageListener(new Listener());
         }
     }

     public Session getSession() {
         return session;
     }

 }

Listener.java 

 import java.text.DecimalFormat;

 import javax.jms.MapMessage;
 import javax.jms.Message;
 import javax.jms.MessageListener;

 public class Listener implements MessageListener {

     public void onMessage(Message message) {
         try {
             MapMessage map = (MapMessage)message;
             String stock = map.getString("stock");
             double price = map.getDouble("price");
             double offer = map.getDouble("offer");
             boolean up = map.getBoolean("up");
             DecimalFormat df = new DecimalFormat( "#,###,###,##0.00" );
             System.out.println(stock + "\t" + df.format(price) + "\t" + df.format(offer) + "\t" + (up?"up":"down"));
         } catch (Exception e) {
             e.printStackTrace();
         }
     }

 }

先运行Consumer.java, 输入参数ORCL，然后运行Publisher.java，输入参数ORCL， 
就可以看到Publisher在发送消息，Consumer在接收消息了。 
（不知道怎么在ECLIPSE里带参数运行程序的，请自行GOOGLE。） 
好了，MQ的安装与第一个示例程序的介绍就到此为止了。 

下一节将介绍JMS的一些概念以帮助我们进行后续的学习。