JMS与Spring之一(用JmsTemplate同步收发消息)

在Spring框架中使用JMS传递消息有两种方式:JMS template和message listener container,前者用于同步收发消息,后者用于异步收发消息。

本文主要讲述用JMS template同步收发消息。

1.       JMS template综述

使用JmsTemplate收发消息可以显著减少开发的精力投入。使用JmsTemplate时,不需要费心考虑连接到JMS provider(如ActiveMQ),建立JMS Session(如QueueSession),建立消息生产者(如QueueSender),甚至不用新建一个JMS消息(如TextMessage)。JmsTemplate能够自动将各种类型如String、Byte[]等转换为响应的JMS消息对象类型,当然也可以自己写Converter转换复杂的消息。

JmsTemplate常用的方法有send、convertAndSend、receive和convertAndReceive。

2.       详细步骤

下面通过一个例子详细讲解使用JmsTemplate同步收发消息。

(1)       环境

JMS1.1;apache-activemq-5.4.0;Spring-2.5.4;JDK-1.5;myeclipse7.5

(2)       源代码(Java Project)

i)                结构

JMS与Spring之一(用JmsTemplate同步收发消息)

ii)              源代码

.classpath:

<?xml version="1.0" encoding="UTF-8"?>

<classpath>

         <classpathentry kind="src" path="src/main/java"/>

         <classpathentry kind="src" path="src/main/resources"/>

         <classpathentry exported="true" kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>

         <classpathentry exported="true" kind="lib" path="lib/jms-1.1.jar"/>

         <classpathentry exported="true" kind="lib" path="lib/spring.jar"/>

         <classpathentry exported="true" kind="lib" path="lib/activemq-all-5.4.0.jar"/>

         <classpathentry kind="output" path="bin"/>

</classpath>

 jndi.properties:

java.naming.factory.initial = org.apache.activemq.jndi.ActiveMQInitialContextFactory

java.naming.provider.url = tcp://localhost:61616

java.naming.security.principal=system

java.naming.security.credentials=manager

connectionFactoryNames = QueueCF

queue.queue1 = jms.queue1

 app-context.xml:

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

            xmlns:jms="http://www.springframework.org/schema/jms"

       xsi:schemaLocation="

       http://www.springframework.org/schema/beans spring-beans-2.0.xsd

            http://www.springframework.org/schema/jms

            http://www.springframework.org/schema/jms/spring-jms-2.5.xsd">

 

         <bean id="jndiTemplate" class="org.springframework.jndi.JndiTemplate">

       <property name="environment">

          <props>

             <prop key="java.naming.factory.initial">

                   org.apache.activemq.jndi.ActiveMQInitialContextFactory</prop>

             <prop key="java.naming.provider.url">tcp://localhost:61616</prop>

             <prop key="java.naming.security.principal">system</prop>

             <prop key="java.naming.security.credentials">manager</prop>

          </props>

       </property>

    </bean>  

         <bean id="jndiQueueConnectionFactory" class="org.springframework.jndi.JndiObjectFactoryBean">

       <property name="jndiTemplate" ref="jndiTemplate"/>

       <property name="jndiName" value="QueueCF"/>

    </bean>  

    <bean id="queueConnectionFactory" class="org.springframework.jms.connection.CachingConnectionFactory">

        <property name="targetConnectionFactory" ref="jndiQueueConnectionFactory"/>

        <property name="sessionCacheSize" value="1"/>

    </bean> 

         <bean id="queueDestination"

            class="org.springframework.jndi.JndiObjectFactoryBean">

            <property name="jndiTemplate" ref="jndiTemplate"/>

            <property name="jndiName" value="queue1"/>

         </bean> 

         <bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate">

            <property name="connectionFactory" ref="queueConnectionFactory"/>

            <property name="defaultDestinationName" value="queue1"/>

            <property name="pubSubDomain" value="false"/>

         </bean>         

         <bean id="jmsSender" class="com.jms.client.JMSSender">

            <property name="jmsTemplate" ref="jmsTemplate"/>

            <property name="queueName" value="queue1"/>

         </bean> 

</beans>

 JMSReceiverSync.java:

package com.jms.server; 

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import org.springframework.jms.core.JmsTemplate;

 

public class JMSReceiverSync { 

         public static void main(String[] args) {                  

                   try {

                            ApplicationContext ctx =

                                     new ClassPathXmlApplicationContext("app-context.xml");

                            JmsTemplate jmsTemplate = (JmsTemplate)ctx.getBean("jmsTemplate"); 

                            int counter = 0;

                            while(counter < 10) {

                    Object msg = jmsTemplate.receiveAndConvert();

                    if (msg instanceof String) {

                             System.out.println("Received: " + msg);

                    }

                    counter++;

                            }                           

                            System.exit(0);

                   } catch (Exception up) {

                            up.printStackTrace();

                   }

         }

}

 JMSSender.java:

package com.jms.client; 

import javax.jms.JMSException;

import javax.jms.Message;

import javax.jms.Session;

import javax.jms.TextMessage;

import org.springframework.jms.core.JmsTemplate;

import org.springframework.jms.core.MessageCreator; 

public class JMSSender { 

         public void sendMessage() throws Exception { 

                   MessageCreator msg = new MessageCreator() {

                            public Message createMessage(Session session)throws JMSException {

                                     TextMessage msg = session.createTextMessage("TEST 1");

                          return msg;

                 }

                   };                           

                   jmsTemplate.send(queueName, msg);

                   System.out.println("Message Sent...");                                

         }

 

         public JmsTemplate jmsTemplate = null;

         public String queueName = null;        

         public void setJmsTemplate(JmsTemplate jmsTemplate) {

                   this.jmsTemplate = jmsTemplate;

         }        

         public void setQueueName(String queueName) {

                   this.queueName = queueName;

         }

}

 JMSSenderApp.java:

package com.jms.client; 

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext; 

public class JMSSenderApp { 

         public static void main(String[] args) {                  

             try {

                            ApplicationContext ctx =

                                     new ClassPathXmlApplicationContext("app-context.xml");

                            JMSSender jmsSender = (JMSSender)ctx.getBean("jmsSender");

                            jmsSender.sendMessage();

             System.exit(0);

             } catch (Exception exception) {

                 exception.printStackTrace();

             }

         }      

} 

 (3)       说明

可以看到,用JmsTemplate收发消息非常简单,因为JmsTemplate几乎帮我们做了大多数的工作,相关关系如下图所示(可结合app-context.xml理解):

JMS与Spring之一(用JmsTemplate同步收发消息)

    步骤与不使用Spring相似,只是都是通过配置完成的。

3.       疑惑

明明用app-context.xml就包含所有的上下文信息了,可是删掉jndi.properties依然会出错。

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