Java list内根据对象属性对对象进行排序

			List<BeanWifiAppoint> list = beanWifiAppointService.findbyWifiName(map);
			
			if (!ValidateUtils.isEmptyForCollection(list)) {

				//根据预约时间的先后对对象进行排序
				Collections.sort(list, new Comparator<BeanWifiAppoint>(){

					@Override
					public int compare(BeanWifiAppoint t1, BeanWifiAppoint t2) {
						 if(t1.getAppointTime().before(t2.getAppointTime())){//如果t1的时间比t2早
			                 return -1;//1是升序，-1是降序，0是不变
			             }
						 else if(t1.getAppointTime().after(t2.getAppointTime())){
							 return 1;
						}
						 else {
							 return 0;
						}
					}
				});
				System.out.println(list);