一个基于Mule的企业服务总线的案例

原文地址： http://www.theserverside.com/tt/articles/article.tss?l=CaseStudyMule

面向服务架构的关键字之一就是ESB。以前很多厂商靠买消息服务器来提供集成交互的方案，然后出现了SOAP和REST。

早期的尝试基本上都是通过定一个固定的消息格式，例如xml来让各个系统交换。但是这些消息格式本身经常需要修订，就给集成带来了很大的麻烦。

最好的解决方案就是每个应用还是用自己支持的接口，例如EDI或者SOAP，然后构建一个可以集成各种结构的聚合器，每一个应用的接口就开发成聚合器的一个端口。这样一个cobol写的应用就可以和一个j2me的应用交互，而不需要知道彼此的技术细节。

常见ESB供应商比较

Product	Vendor	Connects with...
Matrix BusinessWorks	TIBCO	SOAP, EMS, JMS, Rendezvous, MQ, BPEL
Mule ESB	Open-source, MuleSource, Inc.	SOAP, REST, JMS, MQ, JBI, AQ, Caching, JavaSpaces, GigaSpaces, Email, IM, JCA, AS400 Data Queues, System I/O.
OpenESB	Open-source, Sun Microsystems	JBI, JCA, JAX-RPC, JAX-WS
Sonic ESB	Progress Software	JMS, SOAP, JMX
Websphere ESB	IBM	JMS, MQ, SOAP; requires additional adapters to interface with other products and legacy protocols; requires Websphere to work

这里少了一个ServiceMix。

下面是这个案例的细节：

本案例用到的程序包括：

AMD-based 2.6 GHz 4 GB RAM, and Intel-based 3 GHz 4 GB RAM servers

Solaris 10 and Ubuntu Linux Dapper Drake

Java Run-time Environment 1.5.9

Mule current general availability package

A commercial JMS provider

Commercial applications for order capture, inventory management, order management, fulfillment, and reporting

假设有一个项目要集成很多企业级应用程序，出于开发周期的压力，我们选择集成而非重新构建的策略。也就是说order capture, inventory management, order management, fulfillment, and reporting 这些都购买现成的厂商的，我们只需要集中开发一个内容管理系统。

通过和其它六家厂商的协商，他们都提供了JMS和SOAP的接口。因此我们需要一个专业的JMS服务器。

下面我们来看看配置文件：

< mule-configuration id ="Enterprise-Applications-Mashup" version ="1.0" >

首先定义一个Mule和JMS交互的连接器，相当于一个连接池
< connector name ="jmsConnector" className ="org.mule.providers.jms.JmsConnector" >
< properties >
< property name ="jndiProviderUrl"
value ="bitjmsnaming://172.28.63.209:7222" />
< property name ="connectionFactoryJndiName"
value ="QueueConnectionFactory" />
< map name ="jndiProviderProperties" >
< property name ="java.naming.factory.initial"
value ="com.bitco.bitjms.naming.bitjmsInitialContextFactory" />
< property name ="java.naming.security.principal" value ="admin" />
< property name ="java.naming.security.credentials" value ="" />
</ map >
< property name ="username" value ="admin" />
< property name ="password" value ="" />
</ properties >
</ connector >
然后定义一些端点，每个端点都是一个外部供应商程序的接口
< global-endpoints >
< endpoint name ="inJMSGTA" address ="jms://q.gta.in" connector ="jmsConnector" />
< endpoint name ="inJMSSeebelle" address ="jms://q.seebelle.in" connector ="jmsConnector" />
< endpoint name ="inJMSYenta" address ="jms://q.yenta.in" connector ="jmsConnector" />
< endpoint name ="inJMSCatwire" address ="jms://q.catwire.in" connector ="jmsConnector" />
< endpoint name ="inJMSBitco" address ="jms://q.bitco.in" connector ="jmsConnector" />
< endpoint name ="outJMSGTA" address ="jms://q.gta.out" connector ="jmsConnector" />
< endpoint name ="outJMSSeebelle" address ="jms://q.seebelle.out" connector ="jmsConnector" />
< endpoint name ="outJMSYenta" address ="jms://q.yenta.out" connector ="jmsConnector" />
< endpoint name ="outJMSCatwire" address ="jms://q.catwire.out" connector ="jmsConnector" />
< endpoint name ="outJMSBitco" address ="jms://q.bitco.out" connector ="jmsConnector" />
< endpoint name ="console" address ="stream://System.out" />
</ global-endpoints >

< transformers >
< transformer name ="JMSMessageToObject"
className ="org.mule.providers.jms.transformers.JMSMessageToObject" />
< transformer name ="ObjectToString"
className ="org.mule.transformers.simple.ObjectToString" />
</ transformers >

< model name ="Enterprise-Applications-Mashup-JMS" >
< mule-descriptor name ="JMSMessageSwitchboard"
implementation ="org.mule.components.simple.PassThroughComponent" >
系统只有一个inbound，也就是进入系统消息的定义，端口名称叫做outJMSBitco，也就是说outJMSBitco发出一个指令，进入总线，然后Mule把这个消息转换后发送给其它所有的outbound-router，离开总线，进入别的应用程序。
< inbound-router >
< global-endpoint name ="outJMSBitco" />
</ inbound-router >

< outbound-router match-all ="true" >
< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSYenta" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter"
expression ="OrderHistoryRequest" />
</ router >

以下面这条为例：
这条路由的意思是，将消息通过JMS发送给Siebel，JMS的头要标上OrderHistoryResonse，这样Siebel的消息队列受到一条这个消息，Siebel知道对方要做什么操作，将OrderHistory查询出来。
< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSSiebel" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter"
expression ="OrderHistoryResponse" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSCatwire" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="item" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSCatwire" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="item_mapping" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSYenta" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="PAMInventoryUpdate" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSGTA" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="CustomerSearchRequest" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSSiebel" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="CustomerSearchResponse" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSYenta" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="OrderDetailsRequest" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSSiebel" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="OrderDetailsResponse" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSYenta" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="OrderAddUpdRequest" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSSiebel" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="OrderAddUpdResponse" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSYenta" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="catwireCreateItem" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSGTA" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="catalogupdate" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSGTA" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="productupdate" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSGTA" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="skuupdate" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSYenta" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="gtaCreateOrder" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSYenta" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="gtaGetOrderDetails" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="openJmsOutbound" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="XXXOrderUpdate" />
</ router >

< router className ="org.mule.routing.outbound.FilteringOutboundRouter" >
< global-endpoint name ="inJMSBitco" />
< filter className ="org.mule.samples.jms.JMSHeaderFilter" expression ="OrderRelease" />
</ router >
这个端口的意思是把消息打印在DOS窗口上
< router className ="org.mule.routing.outbound.OutboundPassThroughRouter" >
< endpoint address ="stream://System.out" transformers ="ObjectToString" />
</ router >
</ outbound-router >
</ mule-descriptor >
</ model >
</ mule-configuration >