java对象集合时间日期格式字段排序

private List listSort(List list) {
   Collections.sort(list, new Comparator() {
      SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

      public int compare(OrderEntity o1, OrderEntity o2) {
         try {
            Date dt1 = sf.parse(o1.getCreatetime().toString());
            Date dt2 = sf.parse(o2.getCreatetime().toString());
            if (dt1.getTime() > dt2.getTime()) {
               return -1;
            } else if (dt1.getTime() < dt2.getTime()) {
               return 1;
            } else {
               return 0;
            }
         } catch (Exception e) {
            e.printStackTrace();
         }
         return 0;
      }
   });

   return list;
}