当使用jbpm时，正常情况下是要显示未知数量的业务表单页面。
一般情况下，在使用struts2(本人使用的情况下)的一般情况下，页面控制是已经写在struts的配置文件当中，也就是说要显示的页面基本是已知的了(未知页面，显然是无法配置的)，因此一般情况下，当有新业务时，或者业务流程发生变化时(任务节点新增与删除等)，就会导致业务表单页面的新增与删除，然后这种以xml配置方式，显然是无法满足需求的。
我们知道在使用springmvc时，viewname是可以在程序里指定，这样业务表单也是可以在程序里指定的，可以避免xml配置的不灵活性。显然struts2肯定也应该提供了这样的方式。
扩展以下两个类即可：
1、StrutsActionProxyFactory；
2、DefaultActionInvocation；
我们需要覆盖DefaultActionInvocation.createResult方法，
因为该方法的默认实现是从resultmappings里根据resultcode（action相关方法返回值）获取视图的，因此如果业务表单为在struts2的配置文件里进行配置，应该是会抛出异常。因此，我们只要覆盖该方法，并根据resultcode寻找视图(而不是从resultmapping里寻找)。一般情况，resultcode可以是业务表单页面的相对路径。
为了使用我们自己的ActionInvocation，就必须覆盖StrutsActionProxyFactory.createActionProxy方法，因为该方法已经指定返回StrutsActionProxy，我们覆盖StrutsActionProxyFactory.createActionProxy方法，返回我们自己的ActionInvocation。
具体实现如下：
public class IcomStrutsActionInvocation extends DefaultActionInvocation {
public static final String JBPM_PREFIX = "icom:";
public IcomStrutsActionInvocation(Map<String, Object> extraContext, boolean pushAction) {
super(extraContext, pushAction);
}
/**
*
*/
private static final long serialVersionUID = 1L;
public Result createResult() throws Exception {
if (resultCode != null && resultCode.startsWith(JBPM_PREFIX)) {// 如果是工作流表单(返回代码必须以icom:开头哦)
Map<String, String> resultParams = new HashMap<String, String>();
resultParams.put("location", resultCode.replace(JBPM_PREFIX, ""));
ResultConfig resultConfig = new ResultConfig.Builder(resultCode,
ServletDispatcherResult.class.getName()).addParams(resultParams)
.build();
return objectFactory.buildResult(resultConfig, invocationContext
.getContextMap());
} else {
return super.createResult();
}
}
}
public class IcomStrtuts2ActionFactory extends StrutsActionProxyFactory {
public ActionProxy createActionProxy(String namespace, String actionName,
String methodName, Map<String, Object> extraContext,
boolean executeResult, boolean cleanupContext) {
ActionInvocation inv = new IcomStrutsActionInvocation(extraContext, true);
container.inject(inv);
return super.createActionProxy(inv, namespace, actionName, methodName, executeResult, cleanupContext);
}
}
因为struts-default.xml文件是没有配置我们自己的实现类，因此需要在struts的配置文件添加我们自己的相关实现类，配置如下：
<struts>
<bean class="com.icom.tech.struts2.IcomStrtuts2ActionFactory"
name="default" type="com.opensymphony.xwork2.ActionProxyFactory" />
...
</struts>
struts-action返回resultcode例子：
public String forTask() throws Exception {
TaskService taskService = processEngine.getTaskService();
task = taskService.getTask(taskId);
if (null == task)
throw new NullPointerException("id为：" + taskId + " 的任务已经被处理...");
taskService.getVariableNames(taskId);
Map<String, Object> variables = taskService.getVariables(taskId,
taskService.getVariableNames(taskId));
if (!(null == variables || variables.isEmpty())) {
ValueStack stack = ActionContext.getContext().getValueStack();
Iterator<String> it = variables.keySet().iterator();
while (it.hasNext()) {
String key = it.next();
logger.info("将要压入的参数：" + key + " 值为：" + variables.get(key));
Object value = variables.get(key);
stack.set(key, value);
}
}
if(flag){
// 获取表单页面路径信息
return IcomStrutsActionInvocation.JBPM_PREFIX+retriveFormResource();
}
return IcomStrutsActionInvocation.JBPM_PREFIX
+ task.getFormResourceName();
}
private String retriveFormResource() throws Exception {
String formResourceName = task.getFormResourceName();
String excutionId = task.getExecutionId();
Execution e = processEngine.getExecutionService().findExecutionById(
excutionId);
ProcessDefinition pd = processEngine.getRepositoryService()
.createProcessDefinitionQuery().processDefinitionId(
e.getProcessDefinitionId()).uniqueResult();
DeploymentImpl deployment = (DeploymentImpl) processEngine
.getRepositoryService().createDeploymentQuery().deploymentId(
pd.getDeploymentId()).uniqueResult();
String path = deployment.getId() + "/" + pd.getId() + "/"
+ formResourceName;
File formFile = new File(formBaseDir, path);
// 首先判断文件是否存在，不存在则创建表单文件
if (!formFile.exists())
synchronized (processEngine) {
if(!formFile.getParentFile().exists()){
formFile.getParentFile().mkdirs();
}
byte[] buf = deployment.getBytes(formResourceName);
// 写入特定存放目录中
FileOutputStream fos = new FileOutputStream(formFile);
fos.write(buf);
fos.close();
}
return DEFAULT_FORM_BASE_DIR + path;
}
以下是jpdl编写的流程定义文件片段：
<task assignee="${user}" name="材料补正" form="printSupplyMaterial.jsp">
<on event="start">
<event-listener factory="businessInstanceListener" method="getInstance" />
</on>
<on event="timeout">
<timer duedate="${tc_supplyMaterial_timeout}" />
<event-listener class="com.icom.cpb.workflow.listener.ChangeColorListener" auto-wire="true" >
<property name="fontColor">
<string value="${tc_supplyMaterial_timeout_color}"/>
</property>
<property name="businessInstanceService">
<ref object="businessInstanceService"/>
</property>
</event-listener>
</on>
<transition name="未补全" to="不受理" >
<event-listener class="com.icom.cpb.workflow.listener.IncreaseDocNumberListner" >
<property name="userInfoService">
<ref object="userInfoService" />
</property>
<property name="docNumberService">
<ref object="docNumberService" />
</property>
<property name="docnumberName">
<string value="不予受理" />
</property>
<property name="variableName">
<string value="recode" />
</property>
</event-listener>
<event-listener class="com.icom.cpb.workflow.listener.ResetCreateTimeListener">
<property name="businessInstanceService">
<ref object="businessInstanceService"/>
</property>
</event-listener>
</transition>
<!--
<transition name="已补全" to="受理" >
<event-listener class="com.icom.cpb.workflow.listener.IncreaseDocNumberListner" >
<property name="userInfoService">
<ref object="userInfoService" />
</property>
<property name="docNumberService">
<ref object="docNumberService" />
</property>
<property name="docnumberName">
<string value="受理" />
</property>
<property name="variableName">
<string value="accode" />
</property>
</event-listener>
</transition>
-->
<transition name="已补全" to="受理" >
<event-listener class="com.icom.cpb.workflow.listener.ClearMaterialsListener" >
<property name="businessInstanceService">
<ref object="businessInstanceService"/>
</property>
<property name="receivedDocInfoService">
<ref object="receivedDocInfoService"/>
</property>
</event-listener>
<event-listener class="com.icom.cpb.workflow.listener.ResetCreateTimeListener">
<property name="businessInstanceService">
<ref object="businessInstanceService"/>
</property>
</event-listener>
<event-listener class="com.icom.cpb.workflow.listener.IncreaseDocNumberListner" >
<property name="userInfoService">
<ref object="userInfoService" />
</property>
<property name="docNumberService">
<ref object="docNumberService" />
</property>
<property name="docnumberName">
<string value="受理" />
</property>
<property name="variableName">
<string value="accode" />
</property>
</event-listener>
</transition>
</task>