BPEL4WS如何无缝的集成到ESB中

BPEL4WS和ESB不仅不是相互竞争的，反而是互补的。BPEL定义业务流程，而ESB提供BPEL执行过程中所有需要的服务。下面看一个PXE的BPEL过程无缝迁入到ServiceMix里面的例子

这是在PXE中独立执行时候的配置，我们看到ProcessSVC的Provider里面使用了Protocoladapter.soap这个协议提供。其实bpel更不需要关注提供协议的类型，这些服务全部交给ESB做就行了

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<system-descriptor name="AsyncProcess"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.fivesight.com/pxe/system-descriptor/ http://www.fivesight.com/pxe/system-descriptor/"
  wsdlUri="file:main.wsdl"
  xmlns="http://www.fivesight.com/pxe/system-descriptor/"
  xmlns:proc="uri:com.bptest.process"
  xmlns:resp="uri:com.bptest.responder">
  <channels>
    <channel name="inboundChannel" />
    <channel name="callbackChannel" />
    <channel name="outboundChannel" />
  </channels>
  <services>
    <service name="ProcessSVC" provider="uri:protocoladapter.soap">
      <imports>
        <port name="ProcessPORT" type="proc:ProcessPT" channel-ref="inboundChannel"/>
        <port name="CallbackPORT" type="resp:CallbackPT" channel-ref="callbackChannel"/>
      </imports>
    </service>
    <service name="ResponderSVC" provider="uri:protocoladapter.soap">
      <exports>
        <port name="ResponderPORT" type="resp:ResponderPT" channel-ref="outboundChannel"/>
      </exports>
    </service>
    <service name="ProcessSync.BpelService" provider="uri:bpelProvider">
      <imports>
        <port name="AsyncResponder.Responder" type="resp:ResponderPT" channel-ref="outboundChannel"/>
      </imports>
      <exports>
        <port name="Client.Process" type="proc:ProcessPT" channel-ref="inboundChannel"/>
        <port name="AsyncResponder.Caller" type="resp:CallbackPT" channel-ref="callbackChannel"/>
      </exports>
    </service>
  </services>
</system-descriptor>

下面是ServiceMix中的配置。很明显，刚才的provider里面换成了uri:jbi。通过pxe的JBI兼容组件，当业务流程中调用这些组件的时候，自动通过ESB来调用这些服务。

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<system-descriptor name="AsyncProcess"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.fivesight.com/pxe/system-descriptor/ http://www.fivesight.com/pxe/system-descriptor/"
  wsdlUri="file:./AsyncProcess.wsdl"
  xmlns="http://www.fivesight.com/pxe/system-descriptor/"
  xmlns:proc="uri:com.bptest.process"
  xmlns:resp="uri:com.bptest.responder">
  <channels>
    <channel name="inboundChannel" />
    <channel name="callbackChannel" />
    <channel name="outboundChannel" />
  </channels>
  <services>

    <service name="ProcessSVC" provider="uri:jbi" >
      <properties>
        <property name="namespace"
         value="uri:fivesight.com/examples/AsyncProcessJBI" />
      </properties>
      <imports>
        <!-- The following port will be registered as a JBI service endpoint
             {uri:fivesight.com/examples/AsyncProcessJBI:ProcessSVC, ProcessPORT}
          -->
        <port name="ProcessPORT" type="proc:ProcessPT" channel-ref="inboundChannel"/>

        <!-- The following port will be registered as a JBI service endpoint
             {uri:fivesight.com/examples/AsyncProcessJBI:ProcessSVC, CallbackPORT}
          -->
        <port name="CallbackPORT" type="resp:CallbackPT" channel-ref="callbackChannel"/>
      </imports>
    </service>

    <service name="ResponderSVC" provider="uri:jbi" >
      <properties>
        <property name="namespace"
         value="uri:fivesight.com/examples/AsyncProcessJBI" />
      </properties>
      <exports>
        <!-- The following port will invoke JBI service endpoint
             {uri:fivesight.com/examples/AsyncProcessJBI:ResponderSVC, ResponderPORT}
          -->
        <port name="ResponderPORT" type="resp:ResponderPT" channel-ref="outboundChannel"/>
      </exports>
    </service>

    <service name="ProcessSync.BpelService" provider="uri:bpel">
      <properties>
        <property name="compiledProcess" value="AsyncProcess.cbp"/>
      </properties>
      <imports>
        <port name="AsyncResponder.Responder" type="resp:ResponderPT" channel-ref="outboundChannel"/>
      </imports>
      <exports>
        <port name="Client.Process" type="proc:ProcessPT" channel-ref="inboundChannel"/>
        <port name="AsyncResponder.Caller" type="resp:CallbackPT" channel-ref="callbackChannel"/>
      </exports>
    </service>
  </services>
</system-descriptor>