compareTo)--list 根据某字段排序

Collections.sort(actList, new Comparator<Act>() {
   @Override
   public int compare(Act o1, Act o2) {
      return o1.getEndDate().compareTo(o2.getEndDate());//顺序

　　　　/*return o2.getEndDate().compareTo(o1.getEndDate());//降序*/

   }
});