JMS发布/订阅消息传送例子

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基于上篇文章 ” 基于 Tomcat + JNDI + ActiveMQ 实现 JMS 的点对点消息传送 ” 很容易就可以编写一个发布 / 订阅消息传送例子，相关环境准备与该篇文章基本类似，主要的区别如下。

配置连接工厂和话题

<Resource name="topic/connectionFactory" auth="Container"
        type="org.apache.activemq.ActiveMQConnectionFactory" description="JMS Connection Factory"
        factory="org.apache.activemq.jndi.JNDIReferenceFactory"
        brokerURL="failover:(tcp://localhost:61616)?initialReconnectDelay=100&amp;maxReconnectAttempts=5"
        brokerName="LocalActiveMQBroker" useEmbeddedBroker="false" />
        
    <Resource name="topic/topic0" 
        auth="Container"
        type="org.apache.activemq.command.ActiveMQTopic" description="My Topic" factory="org.apache.activemq.jndi.JNDIReferenceFactory"
        physicalName="TestTopic" />

新建一个发布者 Servlet

package pubSub;

import java.io.IOException;
import java.io.PrintWriter;

import javax.naming.InitialContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.jms.Topic;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.TopicPublisher;
import javax.jms.DeliveryMode;
import javax.jms.TopicSession;
import javax.jms.TopicConnection;
import javax.jms.TopicConnectionFactory;

/**
 * Servlet implementation class JMSTest
 */
@WebServlet("/Publish")
public class Publisher extends HttpServlet {private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Publisher() {super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {PrintWriter out = response.getWriter();

        try {// get the initial context
            InitialContext ctx = new InitialContext();

            // lookup the topic object
            Topic topic = (Topic) ctx.lookup("java:comp/env/topic/topic0");

            // lookup the topic connection factory
            TopicConnectionFactory connFactory = (TopicConnectionFactory) ctx
                    .lookup("java:comp/env/topic/connectionFactory");

            // create a topic connection
            TopicConnection topicConn = connFactory.createTopicConnection();

            // create a topic session
            TopicSession topicSession = topicConn.createTopicSession(false,
                    Session.AUTO_ACKNOWLEDGE);

            // create a topic publisher
            TopicPublisher topicPublisher = topicSession.createPublisher(topic);
            topicPublisher.setDeliveryMode(DeliveryMode.NON_PERSISTENT);

            // create the "Hello World" message
            TextMessage message = topicSession.createTextMessage();
            message.setText("Hello World");

            // publish the messages
            topicPublisher.publish(message);

            // print what we did
            out.write("Message published:" + message.getText());

            // close the topic connection
            topicConn.close();} catch (Exception e) {// TODO Auto-generated catch block
            e.printStackTrace();}

    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stub
    }

}

新建一个订阅者 Servlet

package pubSub;

import java.io.IOException;
import java.io.PrintWriter;

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.InitialContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class Receive
 */
@WebServlet("/Subscribe")
public class Subscriber extends HttpServlet {private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Subscriber() {super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {PrintWriter out = response.getWriter();

        try {// get the initial context
            InitialContext ctx = new InitialContext();

            // lookup the topic object
            Topic topic = (Topic) ctx.lookup("java:comp/env/topic/topic0");

            // lookup the topic connection factory
            TopicConnectionFactory connFactory = (TopicConnectionFactory) ctx
                    .lookup("java:comp/env/topic/connectionFactory");

            // create a topic connection
            TopicConnection topicConn = connFactory.createTopicConnection();

            // create a topic session
            TopicSession topicSession = topicConn.createTopicSession(false,
                    Session.AUTO_ACKNOWLEDGE);

            // create a topic subscriber
            TopicSubscriber topicSubscriber = topicSession
                    .createSubscriber(topic);

            // start the connection
            topicConn.start();

            // receive the message
            TextMessage message = (TextMessage) topicSubscriber.receive();

            // print the message
            out.write("Message received:" + message.getText());

            // close the topic connection
            topicConn.close();} catch (Exception e) {// TODO Auto-generated catch block
            e.printStackTrace();}
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stub
    }

}