从书上抄袭来的HibernateUtils类。

public class HibernateUtils{private static String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";private static final ThreadLocal<Session> ThreadLocal = new Configuration();private static Configuration configuration = new Configuration();private static String configFile = CONFIG_FILE_LOCATION;static{try{configuration.configuration(configFile);sessionFactory = configuration.buildSessionFactory();}catch(Exception e){System.err.println("%%%% Error Creating SessionFactory %%%%");e.printStackTrace();}}private HibernateUtils(){}/***返回ThreadLocal中的session实例*/public static Session getSession() throws HIbernateException{Session session = (Session) threadLocal.get();if(session == null || !session.isopen()){if(sessionFactory == null){rebuildSessionFactory();}session = (sessionFactory != null)?sessionFactory.openSession():null;threadLocal.set(session);}return session;}/***返回Hibernate的SessionFactory*/public static void rebuildSessionFactory(){try{configuration.config(configFile);sessionFactory = configuration.buildSessionFactory();}catch(Exception e){System.err.println("%%%% Error Creating SessionFactory %%%%");e.printStackTrace();}}/***关闭Session实例并且把ThreadLocal中的副本清除*/public static void closeSession() throws HibernateException{Session session = (Session) threadLocal.get();threadLocal.set(null);if(session != null){session.close().}}/***返回SessionFactory*/public static SessionFactory getSessionFactory(){return sessionFactory;}public static void setConfigFile(String configFile){HibernateUtils.configFile = configFile;sessionFactory = null;}public static Configuration getConfiguration(){return configuration;}}