Activiti获取某个流程实例的FormKey

通过任务id获得formkey

ProcessDefinitionEntity -->TaskDefinition -->DefaultFormHandler -->Expression.getExpressionText()

用处是用户点击办理任务时可以跳出业务信息的页面，而页面的位置则存放在对应节点的form key中。

HistoricTaskInstance -->ProcessDefinitionEntity -->TaskDefinition-->DefaultFormHandler -->Expression -->Expression.getExpressionText() ;

当前任务是同时存在 ACT_RU_TASK 和 ACT_HI_TASKINST

/**
*
*  @CreateUser:xxxx
*  @ReturnType:String
*  @param taskId
*  @param businessEventId
*  @return
*  @CreateDate:2014-6-10下午7:49:32
*  @UseFor    :根据任务id获得form key值
*/
public String getBusinessInfoUrl(String taskId, String businessEventId) {
String url = "";
String businessKey = "";
// 获得任务对象
HistoricTaskInstance taskInstance = (HistoricTaskInstance) historyService
.createHistoricTaskInstanceQuery().taskId(taskId)
.singleResult();
// 判断当前任务Task是否为空
if (taskInstance != null) {
url = getTaskFormData(taskId);
if (url == null || "".equals(url)) {
String processDefinitionId = taskInstance.getProcessDefinitionId();
url = getProcessDefinitionFormData(processDefinitionId);
}
// 业务id 即eventid
businessKey = ((HistoricProcessInstance) historyService
.createHistoricProcessInstanceQuery()
.processInstanceId(task.getProcessInstanceId())
.singleResult()).getBusinessKey();
} else {
HistoricProcessInstance historicProcessInstance = (HistoricProcessInstance) historyService
.createHistoricProcessInstanceQuery()
.processInstanceBusinessKey(businessEventId).singleResult();
if (historicProcessInstance != null) {
url = getProcessDefinitionFormData(historicProcessInstance
.getProcessDefinitionId());
businessKey = businessEventId;
}
}
// 拼接URL 把eventid接到url上面 url的格式是 xx.htm?eventid=
return (new StringBuilder(String.valueOf(url))).append(businessKey)
.toString();
}
/**
*
*  @CreateUser:xxxx
*  @ReturnType:String
*  @param taskId
*  @return
*  @CreateDate:2014-6-10下午5:21:27
*  @UseFor    :根据任务iD获得form Key 值
*/
private String getTaskFormData(String taskId) {
//表单key值
String formkey = "";
//获取需查询的任务实例
HistoricTaskInstance task = (HistoricTaskInstance) historyService
.createHistoricTaskInstanceQuery().taskId(taskId)
.singleResult();
//获取流程定义对象
ProcessDefinitionEntity processDefinition = getProcessDefinitionEntityByProcessDefinitionId(task
.getProcessDefinitionId());

TaskDefinition taskDefinition = (TaskDefinition) processDefinition
.getTaskDefinitions().get(task.getTaskDefinitionKey());
DefaultFormHandler defaultFormHandler = (DefaultFormHandler) taskDefinition
.getTaskFormHandler();
Expression expression = defaultFormHandler.getFormKey();
if (expression != null)
formkey = expression.getExpressionText();
return formkey;
}

/**
*
*  @CreateUser:xxxx
*  @ReturnType:ProcessDefinitionEntity
*  @param processDefinitionId
*  @return
*  @CreateDate:2014-12-10下午7:39:01
*  @UseFor    :获得 ProcessDefinitionEntity
*/
private ProcessDefinitionEntity getProcessDefinitionEntityByProcessDefinitionId(
String processDefinitionId) {
ProcessDefinitionEntity processDefinitionEntity = (ProcessDefinitionEntity) ((RepositoryServiceImpl) repositoryService)
.getDeployedProcessDefinition(processDefinitionId);
return processDefinitionEntity;
}

/**
*
*  @CreateUser:xxxx
*  @ReturnType:String
*  @param processDefinitionId
*  @return
*  @CreateDate:2014-12-10下午7:38:46
*  @UseFor    :获得第一个节点的Form key
*/
private String getProcessDefinitionFormData(String processDefinitionId) {
StartFormData startFormData = formService
.getStartFormData(processDefinitionId);
return startFormData.getFormKey();
}