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>
<?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！