Hibernate中使用Criteria查询及注解——（HibernateUtil）

package cn.bdqn.hibernate_Criteria.Util;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
  private static Session session;                                                               
  private static ThreadLocal<Session> sl=new ThreadLocal<Session>();                            
  public static  Session getSession(){                                                          
    session=sl.get();                                                                         
    if(session==null){                                                                        
      session=new Configuration().configure().buildSessionFactory().openSession();          
      sl.set(session);                                                                      
    }                                                                                         
    return session;                                                                           
  }                                                                                             
  public static  void closeSession(){                                                           
    session=sl.get();                                                                         
    sl.set(null);                                                                             
    session.close();                                                                          
  }                                                                                             
}