Spring data jpa高级查询，部分字段查询，过滤查询，空字符过滤

        @PersistenceContext
	private EntityManager em;

String hql = "select new WorkflowTask(taskId,versionNum,instanceId,sysId,templateId,templateName,version,taskProcessStatus,taskBusinessStatus,"
			+ "reviewer,assistantReviewer,executant,preNodeName,nodeName,nodeId,taskCreateTime,taskModifyTime,taskType,taskTransferType,taskAssistantType,parentInstanceId,standby1,standby2,standby3,standby4,standby5,relationInstanceId,delegateId,rate,nextRealTaskId,nextPrototypeTaskId,acttaskid,parentstate,reviewerExpression,childFirstTaskId) "
			+ "from  WorkflowTask where 1=1 "+whereHql +" order by taskCreateTime DESC";
		
		TypedQuery query = em.createQuery(hql, WorkflowTask.class);

return query.getResultList();