Spring jms 和 ActiveMQ 开发消息服务

ActiveMQ 是高性能消息中间件，主要针对JMS实现，当然其他语言也可以使用。其支持点对点、发布/订阅、推拉模式，具体看官网，这里略。

1、先下载ActiveMQ，并成功启动服务。

2、建立maven项目，添加依赖

activemq-all-5.6.0.jar

<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-jms</artifactId>
	<version>3.1.1.RELEASE</version>
</dependency>

<dependency>
			<groupId>log4j</groupId>
			<artifactId>log4j</artifactId>
			<version>1.2.16</version>
		</dependency>

3、jms.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:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
         http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
         http://www.springframework.org/schema/context 
         http://www.springframework.org/schema/context/spring-context-3.0.xsd
	     http://www.springframework.org/schema/aop 
	     http://www.springframework.org/schema/aop/spring-aop-3.0.xsd"
	default-autowire="byName" default-lazy-init="false">


	<!-- 连接工厂 -->
	<bean id="connectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
		<property name="brokerURL" value="tcp://127.0.0.1:61616?jms.useAsyncSend=true" />
		<!-- jms.useAsyncSend=true 指定异步方式，性能比同步方式提升5倍 -->
	</bean>


	<!-- 消息列队（目的地） -->
	<bean id="demoQueue" class="org.apache.activemq.command.ActiveMQQueue">
		<constructor-arg value="demo" />
	</bean>
	
</beans>

4、编写发送消息和接收消息的简单java类

public class JmsMQ {


	private JmsTemplate jmsTemplate;
	private Queue demoQueue;


	public void setConnectionFactory(ConnectionFactory connectionFactory) {
		this.jmsTemplate = new JmsTemplate(connectionFactory);
//		this.jmsTemplate.setDeliveryMode(DeliveryMode.NON_PERSISTENT);//消息不持久化
//		this.jmsTemplate.setDeliveryPersistent(false);//消息不持久化
	}


	public void setDemoQueue(Queue demoQueue) {
		this.demoQueue = demoQueue;
	}

	//发送消息
	public void simpleSend(final Long size) {
		this.jmsTemplate.send(this.demoQueue, new MessageCreator() {
			public Message createMessage(Session session) throws JMSException {
				ObjectMessage msg = session.createObjectMessage();
				msg.setObject(size);
				return msg;
			}
		});
	}
	//接收消息
	public void simpleReceive() {
		Message message = jmsTemplate.receive(demoQueue);
		if (message instanceof ObjectMessage) {
			ObjectMessage msg = (ObjectMessage) message;
			Long size;
			try {
				size = (Long) msg.getObject();
				System.out.println("onMessage [" + size + "]");
			} catch (JMSException e) {
				e.printStackTrace();
			}
		} else {
			throw new IllegalArgumentException("Message must be of type ObjectMessage.");
		}
	}


}

5、jmsexample.xml

<bean id="jmsMQ" class="jmsexample.JmsMQ" />

5、编写测试类

public class JmsMQTest {


	public static void main(String[] args) {
		ApplicationContext ctx = new ClassPathXmlApplicationContext("jms.xml", "jmsexample.xml");
		JmsMQ mq = (JmsMQ) ctx.getBean("jmsMQ");
		
		long start = System.currentTimeMillis();
		for(long i=0;i<1000;i++){ 
			mq.simpleSend(i);//发送消息，异步方式下1000次发送7000毫秒。
		}
		System.out.println("耗时：" + (System.currentTimeMillis() - start));
//		
//		long start1 = System.currentTimeMillis();
//		for(long i=0;i<10000;i++){
//			mq.simpleReceive();//获取消息
//		}
//		System.out.println("耗时：" + (System.currentTimeMillis() - start1));
	}


}

上面已经完成了JMS开发过程，测试类包含发送消息，接收消息。但是接收消息是主动的，这种方式叫做“拉”模式。

下面是一个监听指定列队上消息的例子，也就是“推”模式：

1、编写监听消息的java类，需要实现接口

public class ExampleListener implements MessageListener {

	public void onMessage(Message message) {
		if (message instanceof ObjectMessage) {
			ObjectMessage msg = (ObjectMessage) message;
			Long size;
			try {
				size = (Long) msg.getObject();
				System.out.println("onMessage [" + size + "]");
			} catch (JMSException e) {
				e.printStackTrace();
			}
		} else {
			throw new IllegalArgumentException(
					"Message must be of type ObjectMessage.");
		}
	}

}

2、jmsexample-listener.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:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
         http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
         http://www.springframework.org/schema/context 
         http://www.springframework.org/schema/context/spring-context-3.0.xsd
	     http://www.springframework.org/schema/aop 
	     http://www.springframework.org/schema/aop/spring-aop-3.0.xsd"
	default-autowire="byName" default-lazy-init="false">

	<!-- this is the Message Driven POJO (MDP) -->
	<bean id="exampleListener" class="jmsexample.ExampleListener" />

	<!-- and this is the message listener container -->
	<bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
		<property name="connectionFactory" ref="connectionFactory" />
		<property name="destination" ref="demoQueue" />
		<property name="messageListener" ref="exampleListener" />
	</bean>
	
</beans>

3、启动消息监听

/**
 * 监听消息列队
 * */
public class ListenerTest {

	public static void main(String[] args) {
		new ClassPathXmlApplicationContext("jms.xml", "jmsexample-listener.xml");
	}

}

到这里已经讲了推拉模式，发消息和接消息。

另外、Spring对JMS进行了包装，可以将远程方法调用（RPC）封装到JMS中，下面请看JMS实现消息方法调用的过程。

重点：MQ不仅可以缓解系统压力，还可以让系统与系统之间解耦。通过消息传递，可以实现两个系统之间交互。像观察者模式一样，减少了交互对象之间的耦合度。

1、编写接口

public interface CheckingAccountService {

	public void cancelAccount(Long accountId);
	
	public void saveAccount(Long accountId);
}

2、编写实现类

public class SimpleCheckingAccountService implements CheckingAccountService {

    public void cancelAccount(Long accountId) {
        double result = 0D;
		for(int i=0; i<accountId; ){
			result = 31/++i;
		}
		
		System.out.println("Cancelling account [" + accountId + "]" + ",result=" + result);
    }

	public void saveAccount(Long accountId) {
		System.out.println("Saving account [" + accountId + "]");
	}
    
}

3、编写客户端 client.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:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
         http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
         http://www.springframework.org/schema/context 
         http://www.springframework.org/schema/context/spring-context-3.0.xsd
	     http://www.springframework.org/schema/aop 
	     http://www.springframework.org/schema/aop/spring-aop-3.0.xsd" 
	     default-autowire="byName" default-lazy-init="false">
	
	<bean id="checkingAccountService" class="org.springframework.jms.remoting.JmsInvokerProxyFactoryBean"><!-- 这是个工厂，返回接口代理，将方法调用封装为消息，发送到指定列队 -->
        <property name="serviceInterface" value="com.foo.CheckingAccountService"/>
        <property name="connectionFactory" ref="connectionFactory"/>
        <property name="queue" ref="demoQueue"/>
    </bean>
   
</beans>

4、编写服务端 server.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:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
         http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
         http://www.springframework.org/schema/context 
         http://www.springframework.org/schema/context/spring-context-3.0.xsd
	     http://www.springframework.org/schema/aop 
	     http://www.springframework.org/schema/aop/spring-aop-3.0.xsd" 
	     default-autowire="byName" default-lazy-init="false">
	
    <bean id="checkingAccountService" class="org.springframework.jms.remoting.JmsInvokerServiceExporter"><!-- 这是个代理，将接到的消息转换为方法的调用 -->
        <property name="serviceInterface" value="com.foo.CheckingAccountService"/>
        <property name="service">
            <bean class="com.foo.SimpleCheckingAccountService"/>
        </property>
   </bean>
	
	<!-- 监听指定列队-->
   <bean class="org.springframework.jms.listener.SimpleMessageListenerContainer">
       <property name="connectionFactory" ref="connectionFactory"/>
       <property name="destination" ref="demoQueue"/>
       <property name="concurrentConsumers" value="10"/>
       <property name="messageListener" ref="checkingAccountService"/><!-- 当列队有消息，将触发指定方法，形成方法调用 -->
   </bean>
   
</beans>

5、编写测试类  Client.java

/**使用Spring JMS调用服务器端方法*/
public class Client {

	public static void main(String[] args) throws Exception {
		ApplicationContext ctx = new ClassPathXmlApplicationContext("jms.xml", "client.xml");
		CheckingAccountService service = (CheckingAccountService) ctx.getBean("checkingAccountService");
		service.cancelAccount(1000000000L);
		System.out.println("Invoke cancelAccount 1000000000L!");
		
		long start1 = System.currentTimeMillis();
		for(long i=0;i<1000;i++){
			service.saveAccount(i);
		}
		System.out.println("耗时：" + (System.currentTimeMillis() - start1));
	}
}

6、编写测试类 Server.java

public class Server {
//启动服务器，监听列队，获得消息，通过反射调用
	public static void main(String[] args) throws Exception {
		new ClassPathXmlApplicationContext("jms.xml","server.xml");
	}
}

快下班了，细节就不写了，反正这个东西很简单，大家一看明了！