与spring结合

在Spring中嵌入ActiveMQ有四种方式：纯Spring配置文件、在Spring的配置文件中引入ActiveMQ的配置文件、使用硬代码及ActiveMQ配置文件和在Spring配置文件中使用特定的schema。

纯Spring配置文件

<?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:p="http://www.springframework.org/schema/p"  
    xmlns:context="http://www.springframework.org/schema/context"  
    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">  
    
	<bean id="admins" class="org.apache.activemq.security.AuthenticationUser">
		<constructor-arg index="0" value="admin" />
		<constructor-arg index="1" value="password" />
		<constructor-arg index="2" value="admins,publishers,consumers" />
	</bean>
	<bean id="publishers" class="org.apache.activemq.security.AuthenticationUser">
		<constructor-arg index="0" value="publisher" />
		<constructor-arg index="1" value="password" />
		<constructor-arg index="2" value="publishers,consumers" />
	</bean>
	<bean id="consumers" class="org.apache.activemq.security.AuthenticationUser">
		<constructor-arg index="0" value="consumer" />
		<constructor-arg index="1" value="password" />
		<constructor-arg index="2" value="consumers" />
	</bean>
	<bean id="guests" class="org.apache.activemq.security.AuthenticationUser">
		<constructor-arg index="0" value="guest" />
		<constructor-arg index="1" value="password" />
		<constructor-arg index="2" value="guests" />
	</bean>
	<bean id="simpleAuthPlugin" class="org.apache.activemq.security.SimpleAuthenticationPlugin">
		<property name="users">
			<list>
				<ref bean="admins" />
				<ref bean="publishers" />
				<ref bean="consumers" />
				<ref bean="guests" />
			</list>
		</property>
	</bean>
	<bean id="broker" class="org.apache.activemq.broker.BrokerService" init-method="start" destroy-method="stop">
		<property name="brokerName" value="myBroker" />
		<property name="persistent" value="false" />
		<property name="transportConnectorURIs">
			<list>
				<value>tcp://localhost:61616</value>
			</list>
		</property>
		<property name="plugins">
			<list>
				<ref bean="simpleAuthPlugin" />
			</list>
		</property>
	</bean>
</beans>  

在Spring的配置文件中引入ActiveMQ的配置文件

<?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:p="http://www.springframework.org/schema/p"  
    xmlns:context="http://www.springframework.org/schema/context"  
    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">  
    
    <!-- 其他Spring配置 -->
    
	<bean id="broker" class="org.apache.activemq.xbean.BrokerFactoryBean">
		<property name="config" value="activemq.xml" />
		<property name="start" value="true"></property>
	</bean>
</beans>  

硬编码+activemq配置文件方式

public static void main(String[] args) throws Exception {  
        String configUri = MyConfiguration3.class.getResource("/")  
                + "activemq.xml";  
        System.setProperty("activemq.base", System.getProperty("user.dir"));  
        new FileSystemXmlApplicationContext(configUri);  
    }  

使用特定的Schema

<?xml version="1.0" encoding="UTF-8"?>  
<beans xmlns="http://www.springframework.org/schema/beans"  
	<span style="color:#ff0000;">xmlns:amq="http://activemq.apache.org/schema/core"</span>
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"  
    xmlns:context="http://www.springframework.org/schema/context"  
    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
    <span style="color:#ff0000;">http://activemq.apache.org/schema/core
    http://activemq.apache.org/schema/core/activemq-core.xsd</span>
    ">  
    
    <!-- 其他Spring配置 -->
    
	<amq:broker brokerName="myBroker" dataDirectory="${activemq.base}/data">
		<amq:transportConnectors>
			<amq:transportConnector name="openwire" uri="tcp://localhost:61616" />
		</amq:transportConnectors>
		<amq:plugins>
			<amq:simpleAuthenticationPlugin>
				<amq:users>
					<amq:authenticationUser username="admin" password="password" groups="admins,publishers,consumers" />
					<amq:authenticationUser username="publisher" password="password" groups="publishers,consumers" />
					<amq:authenticationUser username="consumer" password="password" groups="consumers" />
					<amq:authenticationUser username="guest" password="password" groups="guests" />
				</amq:users>
			</amq:simpleAuthenticationPlugin>
		</amq:plugins>
	</amq:broker>
</beans>  

客户端配置

<bean id="jmsConnectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
  <property name="brokerURL" value="tcp://localhost:61616" />
  <property name="userName" value="admin" />
  <property name="password" value="password" />
</bean>

可以使用连接池

<bean id="pooledJmsConnectionFactory" class="org.apache.activemq.pool.PooledConnectionFactory" destroy-method="stop">
  <property name="connectionFactory" ref="jmsConnectionFactory" />
</bean>

配置JMS消息目的地

<bean id="cscoDest" class="org.apache.activemq.command.ActiveMQTopic">
  <constructor-arg value="STOCKS.CSCO" />
</bean>
 
<bean id="orclDest" class="org.apache.activemq.command.ActiveMQTopic">
  <constructor-arg value="STOCKS.ORCL" />
</bean>

消息消费者和消息生产者
Spring中接收消息的基本抽象机制是使用消息监听器容器(MLC: 参阅 http://mng.bz/LJti).
MLC是在消息监听器和代理之间设计的中间件,用来处理连接,线程等等,让开发者只需要关注
消息监听器中具体的业务逻辑.

<!-- 这个监听器实现需要自己编写 -->
<bean id="portfolioListener" class="org.apache.activemq.book.ch3.portfolio.Listener">
</bean>
 
<!-- Spring DMLC -->
<bean id="cscoConsumer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
  <property name="connectionFactory" ref="jmsConnectionFactory" />
  <property name="destination" ref="cscoDest" />
  <property name="messageListener" ref="portfolioListener" />
</bean>

<!-- Spring DMLC -->
<bean id="orclConsumer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
  <property name="connectionFactory" ref="jmsConnectionFactory" />
  <property name="destination" ref="orclDest" />
  <property name="messageListener" ref="portfolioListener" />
</bean>

同接收消息一样,Spring同样为发送消息提供了便利.Spring中发送消息的基本机制是使用JmsTemplate类.
JmsTemplate使用标准的模板模式为发送消息提供一个很方便的类.

使用Spring发送消息的一个常用方法是实现Spring的MessageCreator接口然后使用JmsTemplate类中合适
的send()方法

public class StockMessageCreator implements MessageCreator 
{
  private int MAX_DELTA_PERCENT = 1;
  private Map<Destination, Double> LAST_PRICES = new Hashtable<Destination, Double>();
  Destination stock;
 
  public StockMessageCreator(Destination stock) 
  {
    this.stock = stock;
  }
  
  public Message createMessage(Session session) throws JMSException 
  {
    Double value = LAST_PRICES.get(stock);
    if (value == null) 
    {
      value = new Double(Math.random() * 100);
    }
    
    // lets mutate the value by some percentage
    double oldPrice = value.doubleValue();
    value = new Double(mutatePrice(oldPrice));
    LAST_PRICES.put(stock, value);
    double price = value.doubleValue();
    double offer = price * 1.001;
    boolean up = (price > oldPrice);
    MapMessage message = session.createMapMessage();
    message.setString("stock", stock.toString());
    message.setDouble("price", price);
    message.setDouble("offer", offer);
    message.setBoolean("up", up);
    System.out.println("Sending: " + ((ActiveMQMapMessage)message).getContentMap() + " on destination: " + stock);
    return message;
  }
  
  protected double mutatePrice(double price) 
  {
    double percentChange = (2 * Math.random() * MAX_DELTA_PERCENT) - MAX_DELTA_PERCENT;
    return price * (100 + percentChange) / 100;
  }
}

<bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate">
  <property name="connectionFactory" ref="pooledJmsConnectionFactory" />
</bean>

注意JmsTemplate使用了一个池化的连接工厂.这点很重要,因为JmsTemplate是专门设计成使用
Java EE容器的,而Java EE规范要求提供池化连接.每次调用JmsTemplate的send()方法都会创建
和销毁JMS资源(连接,消费者和生产者).因此,如果你没有使用Java EE容器,请确保在利用
JmsTemplate发送消息时使用的是池化的连接工厂.