Collections.sort多个字段排序

//生效日期、操作时间倒序、机型组升序
private void sort(List<IntpathcostAreaGroupstVO> data){
   Comparator<Object> com = Collator.getInstance(java.util.Locale.CHINA);
   Collections.sort(data,new Comparator<IntpathcostAreaGroupstVO>() {
      @Override
      public int compare(IntpathcostAreaGroupstVO o1, IntpathcostAreaGroupstVO o2) {
         String startDate1=DateUtils.date2Str(o1.getStartDate(),DateUtils.YYYY_MM_DD_HHMMSS);//生效日期
         String operateTime1=DateUtils.date2Str(o1.getOperateTime(),DateUtils.YYYY_MM_DD_HHMMSS);//操作时间
         String groupingName1=o1.getGroupingName();//机型组

         String startDate2=DateUtils.date2Str(o2.getStartDate(),DateUtils.YYYY_MM_DD_HHMMSS);//生效日期
         String operateTime2=DateUtils.date2Str(o2.getOperateTime(),DateUtils.YYYY_MM_DD_HHMMSS);//操作时间
         String groupingName2=o2.getGroupingName();//机型组

         int startDate=com.compare(startDate2,startDate1);//倒序
         int operateTime=com.compare(operateTime2,operateTime1);//倒序
         int groupingName=com.compare(groupingName1,groupingName2);//升序

         if(startDate!=0){
            return startDate;
         }else if(operateTime!=0){
            return operateTime;
         }else {
            return groupingName;
         }
      }
   });
}