HibernateUtil类
完成简单增删改查
public final class HibernateUtil {private static SessionFactory sessionFactory;private static ThreadLocal session = new ThreadLocal();private HibernateUtil() {}static {Configuration cfg = new Configuration();cfg.configure();sessionFactory = cfg.buildSessionFactory();}public static Session getThreadLocalSession() {Session s = (Session) session.get();if (s == null) {s = getSession();session.set(s);}return s;}public static void closeSession() {Session s = (Session) session.get();if (s != null) {s.close();session.set(null);}}public static SessionFactory getSessionFactory() {return sessionFactory;}public static Session getSession() {return sessionFactory.openSession();}public static void add(Object entity) {Session s = null;Transaction tx = null;try {s = HibernateUtil.getSession();tx = s.beginTransaction();s.save(entity);tx.commit();} finally {if (s != null)s.close();}}public static void update(Object entity) {Session s = null;Transaction tx = null;try {s = HibernateUtil.getSession();tx = s.beginTransaction();s.update(entity);tx.commit();} finally {if (s != null)s.close();}}public static void delete(Object entity) {Session s = null;Transaction tx = null;try {s = HibernateUtil.getSession();tx = s.beginTransaction();s.delete(entity);tx.commit();} finally {if (s != null)s.close();}}public static Object get(Class clazz, Serializable id) {Session s = null;try {s = HibernateUtil.getSession();Object obj = s.get(clazz, id);return obj;} finally {if (s != null)s.close();}}}