hibernate 为什么会无法使用HibernateUtil.currentSession和 HibernateUtil.closeSession()

[jdynnwxs]

import org.hibernate.Session;
import org.hibernate.Transaction;

import net.sf.ehcache.hibernate.HibernateUtil;

public class PersonManager {
	public static void main(String [] args)
	{
		Session session = HibernateUtil.currentSession();
		Transaction tx = session.beginTransaction();
		Person p = new Person();
		Address a = new Address("Guangzhou tianhe");
		p.setName("crazyit.org");
		p.setAge(21);
		p.setAddress(a);
		session.persist(p);
		Address a2 = new Address("Shanghai hongkou");
		p.setAddress(a2);
		tx.commit();
		HibernateUtil.closeSession();
		
	}
}