hibernate 保留不重复数据

hibernate 保存不重复数据
参考文章
[url]
http://biancheng.dnbcw.info/java/71552.html[/url]

@SuppressWarnings("unchecked")public DeviceInfo getDIByImei(String imei){ArrayList<DeviceInfo> list = (ArrayList<DeviceInfo>)s.createQuery("from DeviceInfo where imei = '"+imei+"'").list();DeviceInfo result = null;if (list.size()>0) {result = list.get(0);}return result;}public void saveOrUpdate(DeviceInfo di){DeviceInfo getDi = getDIByImei(di.getImei());if(getDi==null){DaoFactory.getDiDao().save(di);}}