一个简单的Hibernate工具类HibernateUtil

HibernateUtil

 package com.wj.app.util;

 import org.hibernate.Session;
 import org.hibernate.SessionFactory;
 import org.hibernate.cfg.Configuration;
 import org.hibernate.service.ServiceRegistry;
 import org.hibernate.service.ServiceRegistryBuilder;

 public class HibernateUtil {
     public static final SessionFactory sessionFactory;
     //ThreadLocal可以隔离多个线程的数据共享，因此不需要对线程进行同步
     public static ThreadLocal<Session> session = new ThreadLocal<Session>();
     static
     {
         //使用默认配置文件创建Configuration实例
         Configuration cfg = new Configuration()
                                  .configure();

         //以Configuration实例来创建SessionFactory实例
         ServiceRegistry serviceRegistry = new ServiceRegistryBuilder()
                                                .applySettings(cfg.getProperties())
                                                .buildServiceRegistry();

         /*ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
         .applySettings(cfg.getProperties()).build();*/

         sessionFactory = cfg.buildSessionFactory(serviceRegistry);
     }
     public static Session currentSession() {

         Session s = session.get();
         //如果该线程还没有Session，则创建一个新的Session
         if (s == null)
         {
             s = sessionFactory.openSession();
             //将获得的Session变量存储在ThreadLocal变量session里
             session.set(s);
         }
         return s;
     }

     public static void clossSession() {
         Session s = session.get();
         if (s != null)
         {
             s.close();
         }
         session.set(null);
     }
 }