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);
    }
}