工作流引擎activiti 获取下一节点

CHEEN

最近公司需要使用工作流引擎，选用了activiti。需求中提到的流程比较简单，也就3级审核，送审时需要选择下一节点的用户，所以必须在流程中需要获取当前节点的下一个节点。代码如下：
       /** * 根据实例编号查找下一个任务节点 * @param String procInstId ：实例编号 * @return */public TaskDefinition nextTaskDefinition(String procInstId){//流程标示String processDefinitionId = historyService.createHistoricProcessInstanceQuery().processInstanceId(procInstId).singleResult().getProcessDefinitionId();ProcessDefinitionEntity def = (ProcessDefinitionEntity) ((RepositoryServiceImpl)repositoryService).getDeployedProcessDefinition(processDefinitionId);//执行实例ExecutionEntity execution = (ExecutionEntity) runtimeService.createProcessInstanceQuery().processInstanceId(procInstId).singleResult();//当前实例的执行到哪个节点String activitiId = execution.getActivityId();//获得当前任务的所有节点List<ActivityImpl> activitiList = def.getActivities();String id = null;for(ActivityImpl activityImpl:activitiList){  id = activityImpl.getId(); if(activitiId.equals(id)){System.out.println("当前任务："+activityImpl.getProperty("name"));return nextTaskDefinition(activityImpl, activityImpl.getId(),"${iscorrect==1}");//System.out.println(taskDefinition.getCandidateGroupIdExpressions().toArray()[0]);//return taskDefinition;}}return null;}/** * 下一个任务节点 * @param activityImpl * @param activityId * @param elString * @return */private TaskDefinition nextTaskDefinition(ActivityImpl activityImpl, String activityId, String elString){if("userTask".equals(activityImpl.getProperty("type")) && !activityId.equals(activityImpl.getId())){TaskDefinition taskDefinition = ((UserTaskActivityBehavior)activityImpl.getActivityBehavior()).getTaskDefinition();//taskDefinition.getCandidateGroupIdExpressions().toArray();return taskDefinition;}else{List<PvmTransition> outTransitions = activityImpl.getOutgoingTransitions();List<PvmTransition> outTransitionsTemp = null;for(PvmTransition tr:outTransitions){  PvmActivity ac = tr.getDestination(); //获取线路的终点节点  if("exclusiveGateway".equals(ac.getProperty("type"))){outTransitionsTemp = ac.getOutgoingTransitions();if(outTransitionsTemp.size() == 1){return nextTaskDefinition((ActivityImpl)outTransitionsTemp.get(0).getDestination(), activityId, elString);}else if(outTransitionsTemp.size() > 1){for(PvmTransition tr1 : outTransitionsTemp){Object s = tr1.getProperty("conditionText");if(elString.equals(StrUtils.trim(s.toString()))){return nextTaskDefinition((ActivityImpl)tr1.getDestination(), activityId, elString);}}}}else if("userTask".equals(ac.getProperty("type"))){return ((UserTaskActivityBehavior)((ActivityImpl)ac).getActivityBehavior()).getTaskDefinition();}else{logger.debug(ac.getProperty("type"));}} return null;}}
思路是通过实例ID获取当前节点，然后查找当前节点后后面所有的活动，主要查找的活动是exclusiveGateway和userTask，如果exclusiveGateway中的条件符合${iscorrect==1}就直接查找exclusiveGateway后的活动，直到找到userTask为止。如果当前节点后的活动是userTask，说明这个userTask就是你想要的。


代码中${iscorrect==1}表达式是流程中定义，表示审核通过。当时对于在java中解析表达式遇到困难，所以使用字符串来比较，代码if(elString.equals(StrUtils.trim(s.toString())))就是用于判断表达式。后来发现可以通说juel来解析，以下是解析的代码：
ExpressionFactory factory = new ExpressionFactoryImpl();SimpleContext context = new SimpleContext();context.setVariable("count", factory.createValueExpression(10000, String.class));ValueExpression e = factory.createValueExpression(context, "${count>=1000}", boolean.class);System.out.println(e.getValue(context));