easyui中combotree异步加载的一些问题

1. 先是前台js请求

    //这是dao中的处理    if(department.getDptId() == null){         sql.append("and parent_id is null order by seq asc");  query = this.getSession().createQuery(sql.toString());     }else{         sql.append("and parent_id = :parent_id order by seq asc");     query = this.getSession().createQuery(sql.toString());         query.setParameter("parent_id", department.getDptId());     }