过滤器之Hibernate自动提交事务，并关闭会话

最近我们学到的Hibernate中，有个对房屋信息的查询功能。其中页面的一句代码如下：

package org.newboy.utils;import org.hibernate.HibernateException;import org.hibernate.Session;import org.hibernate.cfg.Configuration;/** * 配置Hibernate工具，对会话工厂和会话进行操作 */public class HibernateUtils {private static String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();private static Configuration configuration = new Configuration();private static org.hibernate.SessionFactory sessionFactory;private static String configFile = CONFIG_FILE_LOCATION;static {try {configuration.configure(configFile);sessionFactory = configuration.buildSessionFactory();} catch (Exception e) {System.err.println("会话工厂创建失败");e.printStackTrace();}}/* * 私有的构造方法 */private HibernateUtils() {}/** * 得到一个线程安全的实例 * * @return Session * @throws HibernateException */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;}/** * 重新建立会话工厂 */public static void rebuildSessionFactory() {try {configuration.configure(configFile);sessionFactory = configuration.buildSessionFactory();} catch (Exception e) {System.err.println("会话工厂创建失败");e.printStackTrace();}}/** * 关闭单个会话实例. * * @throws HibernateException */public static void closeSession() throws HibernateException {Session session = (Session) threadLocal.get();threadLocal.set(null);if (session != null) {session.close();}}/** * 返回会话工厂实例 */public static org.hibernate.SessionFactory getSessionFactory() {return sessionFactory;}/** * 设置配置文件 */public static void setConfigFile(String configFile) {HibernateUtils.configFile = configFile;sessionFactory = null;}/** * 返回配置对象 */public static Configuration getConfiguration() {return configuration;}}
这样每次用户请求就会打开会话和事务，请求结束就提交事务，并关闭会话。解决了上面的问题。