基于内容的路由器

基于内容的路由器首先检查消息的内容，并根据消息中包含的数据把消息路由到不同的通道上。可以根据许多标准来完成路由，如是否存在某些字段、是否有指定的字段值等。实现基于内容的路由器时，由于可能会频繁维护路由器，所以要特别注意路由功能应当易于维护。在更复杂的集成环境中，基于内容的路由器可能会以可配置规则引擎的形式出现，可以根据一组可配置的规则来计算目标通道。

背景：
假设一个公司销售配件（A）和零部件（B），并有两个库存系统，我们需要把新的订单路由到正确的库存系统中以便处理。

代码实现：

新订单
package com.foshanshop.ejb3.app;

import javax.jms.*;
import javax.jms.Queue;
import java.util.*;
import javax.naming.*;

public class QueueSender {

	public static void main(String []args)
	{
		QueueConnection conn=null;
		QueueSession session=null;
		try
		{
			Properties props=new Properties();
			props.setProperty(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
            props.setProperty(Context.PROVIDER_URL, "localhost:1099");
            props.setProperty(Context.URL_PKG_PREFIXES, "org.jboss.naming:org.jnp.interfaces");
            InitialContext ctx = new InitialContext(props);

            QueueConnectionFactory factory=(QueueConnectionFactory)ctx.lookup("QueueConnectionFactory");

            conn=factory.createQueueConnection();

            session=conn.createQueueSession(false, QueueSession.AUTO_ACKNOWLEDGE);

            Destination destination=(Queue)ctx.lookup("queue/FQueue");

            MessageProducer producer=session.createProducer(destination);

            TextMessage msg=session.createTextMessage("w product");

            producer.send(msg);
		}
		catch(Exception e)
		{
			System.out.println("queueSender main has a problem"+":"+e.toString());
		}
	}
}

路由器：

package com.foshanshop.ejb3.impl;

import java.util.Properties;
import javax.jms.*;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.ejb.*;
@MessageDriven(activationConfig={@ActivationConfigProperty(propertyName="destinationType",propertyValue="javax.jms.Queue"),
		@ActivationConfigProperty(propertyName="destination",propertyValue="queue/FQueue"),@ActivationConfigProperty(propertyName="acknowledgeMode",propertyValue="Auto-acknowledge")})

public class FQueueBean implements MessageListener {

	public void onMessage(Message msg) {
		// TODO Auto-generated method stub
		QueueConnection conn=null;
		QueueSession session=null;
		try
		{
			Properties props=new Properties();
			props.setProperty(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
            props.setProperty(Context.PROVIDER_URL, "localhost:1099");
            props.setProperty(Context.URL_PKG_PREFIXES, "org.jboss.naming:org.jnp.interfaces");
            InitialContext ctx = new InitialContext(props);

            QueueConnectionFactory factory=(QueueConnectionFactory)ctx.lookup("QueueConnectionFactory");

            conn=factory.createQueueConnection();

            session=conn.createQueueSession(false, QueueSession.AUTO_ACKNOWLEDGE);

            Destination destinationA=(Queue)ctx.lookup("queue/FQueueA");
            Destination destinationB=(Queue)ctx.lookup("queue/FQueueB");

			if(msg instanceof TextMessage)
			{
				TextMessage tmsg=(TextMessage)msg;
				String text=tmsg.getText();
				if(text.startsWith("w"))
				{
					MessageProducer producer=session.createProducer(destinationA);
					producer.send(msg);
				}
				else if(text.startsWith("s"))
				{
					MessageProducer producer=session.createProducer(destinationB);
					producer.send(msg);
				}
			}
		}
		catch(Exception e)
		{
			System.out.println("FQueueBean has a problem"+":"+e.toString());
		}
	}

}

A库存系统：

package com.foshanshop.ejb3.impl;

import javax.ejb.ActivationConfigProperty;
import javax.ejb.MessageDriven;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;

@MessageDriven(activationConfig={@ActivationConfigProperty(propertyName="destinationType",propertyValue="javax.jms.Queue"),
		@ActivationConfigProperty(propertyName="destination",propertyValue="queue/FQueueA"),@ActivationConfigProperty(propertyName="acknowledgeMode",propertyValue="Auto-acknowledge")})
public class FQueueABean implements MessageListener {

	public void onMessage(Message msg) {
		// TODO Auto-generated method stub
		try
		{
			if(msg instanceof TextMessage)
			{
				TextMessage tmsg=(TextMessage)msg;
				System.out.println("FQueueABean:"+tmsg.getText());
			}
		}
		catch(Exception e)
		{
			System.out.println("there is a problem in FQueueA"+":"+e.toString());
		}
	}

}

B库存系统：

package com.foshanshop.ejb3.impl;

import javax.ejb.ActivationConfigProperty;
import javax.ejb.MessageDriven;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;

@MessageDriven(activationConfig={@ActivationConfigProperty(propertyName="destinationType",propertyValue="javax.jms.Queue"),
		@ActivationConfigProperty(propertyName="destination",propertyValue="queue/FQueueB"),@ActivationConfigProperty(propertyName="acknowledgeMode",propertyValue="Auto-acknowledge")})
public class FQueueBBean implements MessageListener {

	public void onMessage(Message msg) {
		// TODO Auto-generated method stub

		try
		{
			if(msg instanceof TextMessage)
			{
				TextMessage tmsg=(TextMessage)msg;
				System.out.println("FQueueBBean:"+tmsg.getText());
			}
		}
		catch(Exception e)
		{
			System.out.println("there is a problem in FQueueA"+":"+e.toString());
		}
	}

}