JMS笔记-

Jms是Sun为了提供企业级的message server而制定的规范,象JDCBC,JNDI等等规范一样,jms得到了很多厂商的
   支持和实现,象IBM的MQSeries,SonicMQ,Weblogic..  
       jms提供了二个基本模型,pub/sub( publish/subscribe ) 和 P2P ( point to point ). pub/sub model,简单来
   说就是发布订阅模型,在网络中的任一一台机器都可以作为jms的信息发布者(sender)或订阅者(receiver),sender将
   组织完的message放到topics里,receivers从topics里取得message信息,这是一个典型的pull-base model. P2P model
   ,点对点模式,信息发布者将信息放送到queues,client端可以从queues里取得信息,与pub/sub模式不同的是,queues里的
   每一个message只能由一个jms client接受.
       所有的这些机制,均有MOM(Message-oriented Middleware)提供,而对于信息的发布者和接收者来说,他们彼此之间是
   松偶合的,并没有直接的消息通讯,而是通过中间件。这种loosely couple特性,使得jms十分适合在企业信息整合
   (EAI Enterprise Application Integration)中使用.当然，对于企业遗留系统来说，相互之间的信息交换的技术还有很多,
   RPC,XML-RPC,SOAP 都是比较好的技术.jms相比较这些技术,最明显的优势是jms使的信息的发布者和接收者之间是松偶合的，
   并且是异步的。这也提供了良好的扩展性和性能上的优势。

       JMS提供了多种类型的消息.
       1.TextMessage  包含了Java.lang.String为信息的内容,当然也可以存放xml的String类型,灵活性还是比较大的。
       2.ObjectMessage 包含串行化的java对象。
       3.BytesMessage  包含简单的字节数组。
       4.StreamMessage 包含java原始类型的流对象。
       5.MapMessage 包含名称-值对内容,这里的值只能是原始类型或他们的外附对象。

一个实际的例子,首先我们在webogic8.1里建立2个JMS连接工厂,一个给TopicSender使用,另一个则分配给TopicReceiver使用

okay,首先建立TopicSender:

/*
 * Created on 2005-5-7
 *
 */
package org.jjyao.jms;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Properties;

import javax.jms.JMSException;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;
import javax.jms.TopicConnection;
import javax.jms.TopicConnectionFactory;
import javax.jms.TopicPublisher;
import javax.jms.TopicSession;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.rmi.PortableRemoteObject;

import org.apache.log4j.Logger;

/**
 * JMS
 *
 * @author jjyao 2005-5-7
 */
public class TopicSender {

    private final static Logger logger = Logger.getLogger(TopicSender.class);
   
    /**
     * Defines jndi factory name for weblogic
     */
    private final static String JNDI_FACTORY = "weblogic.jndi.WLInitialContextFactory";
   
    /**
     * Defines jndi factory name for jms
     */
    private final static String JMS_FACTORY = "weblogic.jms.TopicConnectionFactory";
   
    /**
     * Defines jndi name for topic
     */
    private final static String TOPIC = "weblogic.jms.topic";
   
    /**
     * Defines the url
     */
    private final static String PROVIDER_URL = "t3://localhost:7001";

    private TopicConnectionFactory tconFactory;

    private TopicConnection tcon;

    private TopicSession tsession;

    private TopicPublisher tPublisher;

    private Topic topic;

    private TextMessage msg;
   
    /**
     *
     * @param ctx
     * @throws ClassCastException
     * @throws NamingException
     * @throws JMSException
     */
    public void init(Context ctx) throws ClassCastException, NamingException, JMSException {

        tconFactory = (TopicConnectionFactory) PortableRemoteObject.narrow(ctx.lookup(JMS_FACTORY),
                TopicConnectionFactory.class);
       
        tcon = tconFactory.createTopicConnection();
        tsession = tcon.createTopicSession(false,Session.AUTO_ACKNOWLEDGE);
        topic = (Topic) PortableRemoteObject.narrow(ctx.lookup(TOPIC),Topic.class);
       
        tPublisher = tsession.createPublisher(topic);
        msg = tsession.createTextMessage();
       
        if(logger.isInfoEnabled()){
            logger.info("tcon : " + tcon);
            logger.info("tsession : " + tsession);
            logger.info("topic : " + topic);
            logger.info("tPublisher : " + tPublisher);
            logger.info("msg : " + msg);
        }
       
        tcon.start();
    }
   
    /**
     *
     * @throws JMSException
     */
    public void close() throws JMSException{
        tPublisher.close();
        tsession.close();
        tcon.close();
    }
   
    /**
     *
     * @param message
     * @throws JMSException
     */
    public void send(String message) throws JMSException{
        this.msg.setText(message);
        this.tPublisher.publish(msg);
    }
   
    /**
     *
     * @param sender
     * @throws IOException
     * @throws JMSException
     */
    protected void readAndSend(TopicSender sender) throws IOException, JMSException{
       
        BufferedReader reader = new BufferedReader( new InputStreamReader(System.in));
        String line = null;
       
        do{
            System.out.println(" Enter message /"quit to quit/" : ");
            line = reader.readLine();
            if(line != null && !"".equals(line)){
                this.send(line);
               
                if(logger.isDebugEnabled()){
                    logger.debug(" Send jms message : " + line);
                }
            }
        }while( line != null && !"QUIT".equalsIgnoreCase(line));  
    }

    public static void main(String[] args) throws Exception {
       
        Properties env = new Properties();
        env.put(Context.SECURITY_PRINCIPAL,"weblogic");
        env.put(Context.SECURITY_CREDENTIALS,"weblogic");
        env.put(Context.INITIAL_CONTEXT_FACTORY, JNDI_FACTORY);
        env.put(Context.PROVIDER_URL, PROVIDER_URL);
        env.put("weblogic.jndi.createIntermediateContexts", "true");
        InitialContext context = new InitialContext(env);
       
        TopicSender topicSender = new TopicSender();
        topicSender.init(context);
        topicSender.readAndSend(topicSender);
        topicSender.close();
    }
}

建立TopicReceive:

/*
 * Created on 2005-5-8
 *
 */
package org.jjyao.jms;

import java.util.Properties;

import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;
import javax.jms.TopicConnection;
import javax.jms.TopicConnectionFactory;
import javax.jms.TopicSession;
import javax.jms.TopicSubscriber;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.rmi.PortableRemoteObject;

import org.apache.log4j.Logger;

/**
 * JMS
 *
 * @author jjyao 2005-5-8
 */
public class TopicReceive implements MessageListener {

    private final static Logger logger = Logger.getLogger(TopicReceive.class);

    /**
     * Defines jndi factory name for weblogic
     */
    private final static String JNDI_FACTORY = "weblogic.jndi.WLInitialContextFactory";

    /**
     * Defines jndi factory name for jms
     */
    private final static String JMS_FACTORY = "weblogic.jms.TopicConnectionFactory_2";

    /**
     * Defines jndi name for topic
     */
    private final static String TOPIC = "weblogic.jms.topic";

    /**
     * Defines the url
     */
    private final static String PROVIDER_URL = "t3://localhost:7001";

    private boolean quit = false;

    private TopicConnectionFactory tconFactory;

    private TopicConnection tcon;

    private TopicSession tsession;

    private TopicSubscriber tSubscriber;

    private Topic topic;
   
   
   
    /**
     *
     */
    public void onMessage(Message msg) {

        String msgText = null;
        try {

            if (msg instanceof TextMessage) {

                msgText = ((TextMessage) msg).getText();

            } else {

                msgText = msg.toString();

            }

            logger.info(" MsgText : " + msgText);
            if ("quit".equals(msgText)) {
                synchronized (this) {
                    this.quit = true;
                    this.notifyAll();
                }
            }

        } catch (JMSException e) {
            logger.error(e, e);
        }

    }
   
    /**
     *
     * @param ctx
     * @throws ClassCastException
     * @throws NamingException
     * @throws JMSException
     */
    private void init(Context ctx) throws ClassCastException, NamingException, JMSException {

        tconFactory = (TopicConnectionFactory) PortableRemoteObject.narrow(
                ctx.lookup(JMS_FACTORY), TopicConnectionFactory.class);
        tcon = tconFactory.createTopicConnection();

        tsession = tcon.createTopicSession(false, Session.AUTO_ACKNOWLEDGE);

        topic = (Topic) PortableRemoteObject.narrow(ctx.lookup(TOPIC), Topic.class);

        tSubscriber = tsession.createSubscriber(topic);
        tSubscriber.setMessageListener(this);

        if (logger.isDebugEnabled()) {
            logger.debug(" tconFactory : " + tconFactory);
            logger.debug(" tcon : " + tcon);
            logger.debug(" tsession : " + tsession);
            logger.debug(" topic : " + topic);
        }

        tcon.start();

    }
   
    /**
     *
     * @throws JMSException
     */
    private void close() throws JMSException {
        tSubscriber.close();
        tsession.close();
        tcon.close();
    }

    public static void main(String[] args) throws Exception {

        Properties env = new Properties();
        env.put(Context.SECURITY_PRINCIPAL, "weblogic");
        env.put(Context.SECURITY_CREDENTIALS, "weblogic");
        env.put(Context.INITIAL_CONTEXT_FACTORY, JNDI_FACTORY);
        env.put(Context.PROVIDER_URL, PROVIDER_URL);
        env.put("weblogic.jndi.createIntermediateContexts", "true");
        InitialContext context = new InitialContext(env);
       
        TopicReceive topicReceive = new TopicReceive();
        topicReceive.init(context);
       
        System.out.println("JMS Ready To Receive Messages (To quit, send a /"quit/" message).");
       
        synchronized(topicReceive){
            while(!topicReceive.quit){
                topicReceive.wait();
            }
        }
        topicReceive.close();
    }
}

一个简单的JMS的pub/sub模型就建立好了...