按照list中实体类的某一属性排序

	public void sort(List<MedicalPracticesDetail> mpdList){
		Collections.sort(mpdList, new Comparator<MedicalPracticesDetail>(){  
			public int compare(MedicalPracticesDetail o1,
					MedicalPracticesDetail o2) {
				return o2.getOperatorTime().compareTo(o1.getOperatorTime());
			}  	      
		}); 
	}