現在假設存在這樣一個流程：

首先需要進行復雜的鑑權，而且可能隨著需求的變化而變化，這導致鑑權的流程也是時刻可能變化的。而只有當鑑權成功以後，才能執行實際的交易操作，例如向外部系統傳送請求報文獲取某些交易的資料。

這時，可以考慮將鑑權流程獨立做成一個子流程，然後將其嵌入到主流程中去，適應區域性流程變化而無需修改全域性流程的問題，在子流程與主流程之間實際要做的就是約定資料的交換協議，即確定資料在子流程與主流程之間的流入與流出。

下面通過一個實際例子來說明並實踐。

首先，定義主流程。

主流程包含鑑權的子流程，鑑權通過之後，收集鑑權過程中獲取到的交易必需的資料，組裝請求報文，流程定義如圖所示：

對應的流程定義檔案main-process.jpdl.xml，如下所示：

 <?xml version="1.0" encoding="UTF-8"?> <process name="MainProcess" xmlns="http://jbpm.org/4.4/jpdl"> <start g="347,93,48,48"> <transition g="-123,-22" name="to SubCheckProcess" to="SubCheckProcess"/> </start> <sub-process g="297,173,149,40" name="SubCheckProcess" sub-process-key="SubCheckProcess"> <parameter-in subvar="myRequest" var="myRequest"/> <parameter-out subvar="myRequest" var="myRequest"/> <transition g="-114,-22" name="to ExternalRequest" to="ExternalRequest"/> </sub-process> <end g="347,329,48,48" name="end"/> <custom class="com.umpay.workflow.jbpm.handler.ExternalRequestHandler" g="306,245,131,52" name="ExternalRequest"> <transition g="-43,-22" name="to end" to="end"/> </custom> </process>

上面，sub-process-key="SubCheckProcess"表示一個嵌入主流程中的鑑權子流程。通過流程定義檔案內容，可以看到，在主流程與子流程之間交換資料，是通過變數myRequest來實現的：

<sub-process g="297,173,149,40" name="SubCheckProcess" sub-process-key="SubCheckProcess"> <parameter-in subvar="myRequest" var="myRequest"/> <parameter-out subvar="myRequest" var="myRequest"/> <transition g="-114,-22" name="to ExternalRequest" to="ExternalRequest"/>

<parameter-in>元素表示從主流程MainProcess中流入到子流程SubCheckProcess中變數為myRequest，而var="myRequest"表示在主流程中變數名稱，而subvar="myRequest"表示在子流程中可以通過獲取到myRequest變數從而得到資料。同理，<parameter-out>元素表示從子流程SubCheckProcess中流出到MainProcess中，將資料又傳回主流程中，繼續後續流程的操作。

另外，主流程在執行完子流程後，又執行了ExternalRequest結點，對應的處理類為com.umpay.workflow.jbpm.handler.ExternalRequestHandler，如下所示：

package com.umpay.workflow.jbpm.handler; import java.util.Map; import org.jbpm.api.activity.ActivityBehaviour; import org.jbpm.api.activity.ActivityExecution; public class ExternalRequestHandler implements ActivityBehaviour { @Override public void execute(ActivityExecution execution) throws Exception { Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest"); System.out.println("Main process variables: " + myRequest); } }

然後，實現子流程。

子流程定義，如圖所示：

對應的流程定義檔案sub-check-process.jpdl.xml，內容如下所示：

<?xml version="1.0" encoding="UTF-8"?> <process name="SubCheckProcess" xmlns="http://jbpm.org/4.4/jpdl"> <start g="332,2,48,52"> <transition g="-112,-22" name="to CheckCustomer" to="CheckCustomer"/> </start> <custom class="com.umpay.workflow.jbpm.handler.CheckCustomerHandler" g="302,86,108,52" name="CheckCustomer"> <transition g="-52,-22" name="to fork1" to="fork1"/> </custom> <custom class="com.umpay.workflow.jbpm.handler.CheckMerHandler" g="186,250,92,52" name="CheckMer"> <transition g="-58,-8" name="to join1" to="join1"/> </custom> <custom class="com.umpay.workflow.jbpm.handler.CheckBankHandler" g="310,250,92,52" name="CheckBank"> <transition name="to join1" to="join1" g="0,-13"/> </custom> <custom class="com.umpay.workflow.jbpm.handler.CheckGoodsHandler" g="434,250,92,52" name="CheckGoods"> <transition name="to join1" to="join1" g="21,-4"/> </custom> <custom class="com.umpay.workflow.jbpm.handler.CheckMerBankHandler" g="295,414,122,52" name="CheckMerBank"> <transition name="to CheckGoodsBank" to="CheckGoodsBank" g="-124,-22"/> </custom> <custom class="com.umpay.workflow.jbpm.handler.CheckGoodsBankHandler" g="289,498,134,52" name="CheckGoodsBank"> <transition name="to end1" to="end1" g="-50,-22"/> </custom> <fork g="332,170,48,48" name="fork1"> <transition g="-80,-22" name="to CheckMer" to="CheckMer"/> <transition g="-46,-13" name="to CheckBank" to="CheckBank"/> <transition g="1,-21" name="to CheckGoods" to="CheckGoods"/> </fork> <join g="332,334,48,48" name="join1"> <transition name="to CheckMerBank" to="CheckMerBank" g="-109,-22"/> </join> <end g="332,582,48,52" name="end1"/> </process>

上面對應了6個處理類，實現分別如下所示：

package com.umpay.workflow.jbpm.handler; import java.util.Map; import org.jbpm.api.activity.ActivityBehaviour; import org.jbpm.api.activity.ActivityExecution; public class CheckCustomerHandler implements ActivityBehaviour { @Override public void execute(ActivityExecution execution) throws Exception { Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest"); String mobileId = (String)myRequest.get("mobileId"); // get system user id : userId=20110001674 myRequest.put("userId", "20110001674"); execution.setVariables(myRequest); } }

package com.umpay.workflow.jbpm.handler; import java.util.Map; import org.jbpm.api.activity.ActivityBehaviour; import org.jbpm.api.activity.ActivityExecution; public class CheckMerHandler implements ActivityBehaviour { @Override public void execute(ActivityExecution execution) throws Exception { Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest"); String mobileId = (String)myRequest.get("mobileId"); // get system user id : userId=20110001674 myRequest.put("userId", "20110001674"); execution.setVariables(myRequest); } }

package com.umpay.workflow.jbpm.handler; import java.util.Map; import org.jbpm.api.activity.ActivityBehaviour; import org.jbpm.api.activity.ActivityExecution; public class CheckBankHandler implements ActivityBehaviour { @Override public void execute(ActivityExecution execution) throws Exception { Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest"); String mobileId = (String)myRequest.get("mobileId"); // get system user id : userId=20110001674 myRequest.put("userId", "20110001674"); execution.setVariables(myRequest); } }

package com.umpay.workflow.jbpm.handler; import java.util.Map; import org.jbpm.api.activity.ActivityBehaviour; import org.jbpm.api.activity.ActivityExecution; public class CheckGoodsHandler implements ActivityBehaviour { @Override public void execute(ActivityExecution execution) throws Exception { Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest"); String goodsId = (String)myRequest.get("goodsId"); // get goods count myRequest.put("goodsCount", "2000"); execution.setVariables(myRequest); } }

package com.umpay.workflow.jbpm.handler; import java.util.Map; import org.jbpm.api.activity.ActivityBehaviour; import org.jbpm.api.activity.ActivityExecution; public class CheckMerBankHandler implements ActivityBehaviour { @Override public void execute(ActivityExecution execution) throws Exception { Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest"); String merId = (String)myRequest.get("merId"); String bankId = (String)myRequest.get("bankId"); // get mer bank relationship myRequest.put("mbr","mbr_" + merId + "_" + bankId); execution.setVariables(myRequest); } }

package com.umpay.workflow.jbpm.handler; import java.util.Map; import org.jbpm.api.activity.ActivityBehaviour; import org.jbpm.api.activity.ActivityExecution; public class CheckGoodsBankHandler implements ActivityBehaviour { @Override public void execute(ActivityExecution execution) throws Exception { Map<String, Object> myRequest = (Map<String, Object>)execution.getVariable("myRequest"); String goodsId = (String)myRequest.get("goodsId"); String bankId = (String)myRequest.get("bankId"); // get goods bank relationship myRequest.put("gbr", "gbr_" + goodsId + "_" + bankId); execution.setVariables(myRequest); } }

在執行子流程的過程中，在每一個節點處處理，都模擬了“獲取到一些額外的必需資料”。

最後，測試用例。

測試用例，如下所示：

package com.umpay.workflow.jbpm.process; import java.util.HashMap; import java.util.Map; import junit.framework.TestCase; import org.jbpm.api.Execution; import org.jbpm.api.ProcessEngine; import org.jbpm.api.ProcessInstance; import org.springframework.context.support.ClassPathXmlApplicationContext; public class MainProcessTest extends TestCase { private ProcessEngine processEngine; private String mainProcessDeploymentId; private String subCheckProcessDeploymentId; protected void setUp() throws Exception { super.setUp(); ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext( "applicationContext.xml"); ctx.start(); this.processEngine = (ProcessEngine) ctx.getBean("processEngine"); mainProcessDeploymentId = this.processEngine .getRepositoryService() .createDeployment() .addResourceFromClasspath( "com/umpay/workflow/jbpm/jpdl/main-process.jpdl.xml") .deploy(); subCheckProcessDeploymentId = this.processEngine .getRepositoryService() .createDeployment() .addResourceFromClasspath( "com/umpay/workflow/jbpm/jpdl/sub-check-process.jpdl.xml") .deploy(); } protected void tearDown() throws Exception { this.processEngine.getRepositoryService().deleteDeploymentCascade( mainProcessDeploymentId); this.processEngine.getRepositoryService().deleteDeploymentCascade( subCheckProcessDeploymentId); super.tearDown(); } public void testMyProcess() { // initialize request data Map<String, Object> myRequest = new HashMap<String, Object>(); myRequest.put("merId", "001"); myRequest.put("mobileId", "13800138000"); myRequest.put("goodsId", "030"); myRequest.put("bankId", "CMPAY010"); Map<String, Object> variables = new HashMap<String, Object>(); variables.put("myRequest", myRequest); ProcessInstance processInstance = null; // start a process instance // it can execute a process automatically processInstance = this.processEngine .getExecutionService().startProcessInstanceByKey("MainProcess", variables); assertEquals(Execution.STATE_ENDED, processInstance.getState()); } }

上述程式，開始要需要部署流程，主流程和子流程需要單獨部署，實際是在這個具體的例子中，存在兩個流程，它們在執行自己的例項的時候是獨立的。在流程啟動之前，需要根據流程執行需要，輸入在流程中能夠獲取到的資料（Key+Value的形式）。接著就可以運行了，可以看到，最終可以看到流程資料的集合 ：

Main process variables: {goodsId=030, mobileId=13800138000, userId=20110001674, merId=001, goodsCount=2000, mbr=mbr_001_CMPAY010, gbr=gbr_030_CMPAY010, bankId=CMPAY010}

這裡，資料集合{userId=20110001674, goodsCount=2000, mbr=mbr_001_CMPAY010, gbr=gbr_030_CMPAY010}都是在執行處理的時候獲取到的交易操作所需要的資料。