基于Tomcat + JNDI + ActiveMQ实现JMS的点对点消息传送

写了一个简单的JMS例子，之所以使用JNDI 是出于通用性考虑，该例子使用JMS规范提供的通用接口，没有使用具体JMS提供者的接口，这样可以保证我们编写的程序适用于任何一种JMS实现(ActiveMQ、HornetQ...)。

什么是JNDI

JNDI(Java Naming and Directory Interface)是一个标准规范，类似于JDBC，JMS等规范，为开发人员提供了查找和访问各种命名和目录服务的通用、统一的接口。J2EE 规范要求所有 J2EE 容器都要提供 JNDI 规范的实现，因此Tomcat就实现了JNDI 规范。

使用Tomcat配置JNDI

　　找到Tomcat安装路径下的conf文件夹，打开context.xml，添加如下配置：

<Resource name="queue/connectionFactory" auth="Container" type="org.apache.activemq.ActiveMQConnectionFactory" description="JMS Connection Factory" factory="org.apache.activemq.jndi.JNDIReferenceFactory" brokerURL="tcp://localhost:61616" brokerName="LocalActiveMQBroker" /> <Resource name="queue/queue0" auth="Container" type="org.apache.activemq.command.ActiveMQQueue" description="My Queue" factory="org.apache.activemq.jndi.JNDIReferenceFactory" physicalName="TomcatQueue" />

启动ActiveMQ

　　CMD到ActiveMQ安装路径下的bin目录，输入“activemq start”指令即可启动，可在浏览器中输入地址:8161/admin，查看队列、话题等信息。

编写一个Web工程

　　eclipse上新建web工程，添加ActiveMQ依赖的jar包，然后开始编写两个Servlet，一个用于生产消息，另一个用于消费消息，如下代码：

消息生产者Servlet：

import java.io.IOException; import java.io.PrintWriter; import javax.jms.DeliveryMode; import javax.jms.Queue; import javax.jms.QueueConnection; import javax.jms.QueueConnectionFactory; import javax.jms.QueueSender; import javax.jms.QueueSession; import javax.jms.Session; import javax.jms.TextMessage; 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 JMSTest */ @WebServlet("/Send") public class Send extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public Send() { 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 context = new InitialContext(); // lookup the queue object Queue queue = (Queue) context.lookup("java:comp/env/queue/queue0"); // lookup the queue connection factory QueueConnectionFactory conFactory = (QueueConnectionFactory) context .lookup("java:comp/env/queue/connectionFactory"); // create a queue connection QueueConnection queConn = conFactory.createQueueConnection(); // create a queue session QueueSession queSession = queConn.createQueueSession(false, Session.DUPS_OK_ACKNOWLEDGE); // create a queue sender QueueSender queSender = queSession.createSender(queue); queSender.setDeliveryMode(DeliveryMode.NON_PERSISTENT); // create a simple message to say "Hello World" TextMessage message = queSession.createTextMessage("Hello World"); // send the message queSender.send(message); // print what we did out.write("Message Sent: " + message.getText()); // close the queue connection queConn.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 } }

消息消费者Servlet：