使用 ActiveMQ 示例-优快云博客

原文出处：http://blog.chenlb.com/2010/01/activemq-hello.html

企业中各项目中相互协作的时候可能用得到消息通知机制。比如有东西更新了，可以通知做索引。

在 Java 里有 JMS 的多个实现。其中 apache 下的 ActiveMQ 就是不错的选择。还有一个比较热的是 RabbitMQ （是 erlang 语言实现的）。这里示例下使用 ActiveMQ

用 ActiveMQ 最好还是了解下 JMS

JMS 公共	点对点域	发布/订阅域
ConnectionFactory	QueueConnectionFactory	TopicConnectionFactory
Connection	QueueConnection	TopicConnection
Destination	Queue	Topic
Session	QueueSession	TopicSession
MessageProducer	QueueSender	TopicPublisher
MessageConsumer	QueueReceiver	TopicSubscriber

JMS 定义了两种方式：Quere（点对点）；Topic（发布/订阅）。

ConnectionFactory 是连接工厂，负责创建Connection。

Connection 负责创建 Session。

Session 创建 MessageProducer（用来发消息）和 MessageConsumer（用来接收消息）。

Destination 是消息的目的地。

详细的可以网上找些 JMS 规范（有中文版）。

下载 apache-activemq-5.3.0。http://activemq.apache.org/download.html ，解压，然后双击 bin/activemq.bat。运行后，可以在 http://localhost:8161/admin 观察。也有 demo， http://localhost:8161/demo 。把 activemq-all-5.3.0.jar 加入 classpath。

Jms 发送代码：

public static void main(String[] args) throws Exception {
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory();
Connection connection = connectionFactory.createConnection();
connection.start();
Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
Destination destination = session.createQueue("my-queue" );
MessageProducer producer = session.createProducer(destination);
for ( int i= 0 ; i< 3 ; i++) {
MapMessage message = session.createMapMessage();
message.setLong("count" , new Date().getTime());
Thread.sleep(1000 );
//通过消息生产者发出消息
producer.send(message);
}
session.commit();
session.close();
connection.close();
}

public static void main(String[] args) throws Exception {
	ConnectionFactory connectionFactory = new ActiveMQConnectionFactory();

	Connection connection = connectionFactory.createConnection();
	connection.start();

	Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
	Destination destination = session.createQueue("my-queue");

	MessageProducer producer = session.createProducer(destination);
	for(int i=0; i<3; i++) {
		MapMessage message = session.createMapMessage();
		message.setLong("count", new Date().getTime());
		Thread.sleep(1000);
		//通过消息生产者发出消息
		producer.send(message);
	}
	session.commit();
	session.close();
	connection.close();
}

Jms 接收代码：

public static void main(String[] args) throws Exception {
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory();
Connection connection = connectionFactory.createConnection();
connection.start();
final Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
Destination destination = session.createQueue("my-queue" );
MessageConsumer consumer = session.createConsumer(destination);
/*//listener 方式
consumer.setMessageListener(new MessageListener() {
public void onMessage(Message msg) {
MapMessage message = (MapMessage) msg;
//TODO something....
System.out.println("收到消息：" + new Date(message.getLong("count")));
session.commit();
}
});
Thread.sleep(30000);
*/
int i= 0 ;
while (i< 3 ) {
i++;
MapMessage message = (MapMessage) consumer.receive();
session.commit();
//TODO something....
System.out.println("收到消息：" + new Date(message.getLong( "count" )));
}
session.close();
connection.close();
}

public static void main(String[] args) throws Exception {
	ConnectionFactory connectionFactory = new ActiveMQConnectionFactory();

	Connection connection = connectionFactory.createConnection();
	connection.start();

	final Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
	Destination destination = session.createQueue("my-queue");

	MessageConsumer consumer = session.createConsumer(destination);
	/*//listener 方式
	consumer.setMessageListener(new MessageListener() {

		public void onMessage(Message msg) {
			MapMessage message = (MapMessage) msg;
			//TODO something....
			System.out.println("收到消息：" + new Date(message.getLong("count")));
			session.commit();
		}

	});
	Thread.sleep(30000);
	*/
	int i=0;
	while(i<3) {
		i++;
		MapMessage message = (MapMessage) consumer.receive();
		session.commit();

		//TODO something....
		System.out.println("收到消息：" + new Date(message.getLong("count")));
	}

	session.close();
	connection.close();
}

启动 JmsReceiver 和 JmsSender 可以在看输出三条时间信息。当然 Jms 还指定有其它格式的数据，如 TextMessage

结合 Spring 的 JmsTemplate 方便用：

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"
xsi:schemaLocation = "http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd" >
<!-- 在非 web / ejb 容器中使用 pool 时，要手动 stop，spring 不会为你执行 destroy-method 的方法
< bean id = "jmsFactory" class = "org.apache.activemq.pool.PooledConnectionFactory" destroy-method = "stop" >
< property name = "connectionFactory" >
< bean class = "org.apache.activemq.ActiveMQConnectionFactory" >
< property name = "brokerURL" value = "tcp://localhost:61616" />
</ bean >
</ property >
</ bean >
-->
< bean id = "jmsFactory" class = "org.apache.activemq.ActiveMQConnectionFactory" >
< property name = "brokerURL" value = "tcp://localhost:61616" />
</ bean >
< bean id = "jmsTemplate" class = "org.springframework.jms.core.JmsTemplate" >
< property name = "connectionFactory" ref = "jmsFactory" />
< property name = "defaultDestination" ref = "destination" />
< property name = "messageConverter" >
< bean class = "org.springframework.jms.support.converter.SimpleMessageConverter" />
</ property >
</ bean >
< bean id = "destination" class = "org.apache.activemq.command.ActiveMQQueue" >
< constructor-arg index = "0" value = "my-queue" />
</ bean >
</ beans >

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<!-- 在非 web / ejb 容器中使用 pool 时，要手动 stop，spring 不会为你执行 destroy-method 的方法
	<bean id="jmsFactory" class="org.apache.activemq.pool.PooledConnectionFactory" destroy-method="stop">
		<property name="connectionFactory">
			<bean class="org.apache.activemq.ActiveMQConnectionFactory">
				<property name="brokerURL" value="tcp://localhost:61616" />
			</bean>
		</property>
	</bean>
-->
	<bean id="jmsFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
		<property name="brokerURL" value="tcp://localhost:61616" />
	</bean>
	<bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate">
		<property name="connectionFactory" ref="jmsFactory" />
		<property name="defaultDestination" ref="destination" />
		<property name="messageConverter">
			<bean class="org.springframework.jms.support.converter.SimpleMessageConverter" />
		</property>
	</bean>

	<bean id="destination" class="org.apache.activemq.command.ActiveMQQueue">
		<constructor-arg index="0" value="my-queue" />
	</bean>

</beans>

sender：

public static void main(String[] args) {
ApplicationContext ctx = new FileSystemXmlApplicationContext( "classpath:app*.xml" );
JmsTemplate jmsTemplate = (JmsTemplate) ctx.getBean("jmsTemplate" );
jmsTemplate.send(new MessageCreator() {
public Message createMessage(Session session) throws JMSException {
MapMessage mm = session.createMapMessage();
mm.setLong("count" , new Date().getTime());
return mm;
}
});
}

public static void main(String[] args) {
	ApplicationContext ctx = new FileSystemXmlApplicationContext("classpath:app*.xml");

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

	jmsTemplate.send(new MessageCreator() {

		public Message createMessage(Session session) throws JMSException {
			MapMessage mm = session.createMapMessage();
			mm.setLong("count", new Date().getTime());
			return mm;
		}

	});
}

receiver：

public static void main(String[] args) {
ApplicationContext ctx = new FileSystemXmlApplicationContext( "classpath:app*.xml" );
JmsTemplate jmsTemplate = (JmsTemplate) ctx.getBean("jmsTemplate" );
while ( true ) {
Map<String, Object> mm = (Map<String, Object>) jmsTemplate.receiveAndConvert();
System.out.println("收到消息：" + new Date((Long)mm.get( "count" )));
}
}

public static void main(String[] args) {
	ApplicationContext ctx = new FileSystemXmlApplicationContext("classpath:app*.xml");

	JmsTemplate jmsTemplate = (JmsTemplate) ctx.getBean("jmsTemplate");
	while(true) {
		Map<String, Object> mm =  (Map<String, Object>) jmsTemplate.receiveAndConvert();
		System.out.println("收到消息：" + new Date((Long)mm.get("count")));
	}
}

注意：直接用 Jms 接口时接收了消息后要提交一下，否则下次启动接收者时还可以收到旧数据。有了 JmsTemplate 就不用自己提交 session.commit() 了。如果使用了 PooledConnectionFactory 要把 apache-activemq-5.3.0\lib\optional\activemq-pool-5.3.0.jar 加到 classpath

参考资料：

Hello ActiveMQ

Spring2.5整合ActiveMQ 5.2

spring-support

JMS 相关资料