import org.hibernate.HibernateException;  import org.hibernate.Session;  import org.hibernate.SessionFactory;  import org.hibernate.cfg.Configuration;    public class HibernateUtil {        PRivate static SessionFactory sessionFactory = null;        static {          try {              Configuration cfg = new Configuration().configure();              sessionFactory = cfg.buildSessionFactory();          } catch (HibernateException e) {              // TODO: handle exception              e.printStackTrace();          }      }        public static SessionFactory getSessionFactory() {          return sessionFactory;      }        public static Session getSession() {          Session session = (sessionFactory != null) ? sessionFactory.openSession() : null;          return session;      }        public static void closeFactory(Session session) {          if (session != null) {              if (session.isOpen()) {                  session.close();              }          }      }  }  

1.這個工具類可以直接使用獲取session（static方法） 但是需要注意的是這個類不是線程安全的 hibernate提倡用線程安全的工具類

2.具體過程可以理解為得到Configuration對象--->得到session工廠 sessionFactory--->獲得session openSession();最終調用session的各種方法進行數據操作。

3.可以參考hibernate文檔 有非常詳細的介紹 hibernate-distribution-3.3.2.GA/documentation/manual/zh-CN 中文版在document文件夾下

文檔內容

It is time to load and store someEventobjects, but first you have to complete the setup with some infrastructure code. You have to startup Hibernate by building a globalorg.hibernate.SessionFactoryobject and storing it somewhere for easy access in application code. Aorg.hibernate.SessionFactoryis used to obtainorg.hibernate.Sessioninstances. Aorg.hibernate.Sessionrepresents a single-threaded unit of work. Theorg.hibernate.SessionFactoryis a thread-safe global object that is instantiated once.

We will create aHibernateUtilhelper class that takes care of startup and makes accessing theorg.hibernate.SessionFactorymore convenient.

package org.hibernate.tutorial.util;    import org.hibernate.SessionFactory;  import org.hibernate.cfg.Configuration;    public class HibernateUtil {        private static final SessionFactory sessionFactory = buildSessionFactory();        private static SessionFactory buildSessionFactory() {          try {              // Create the SessionFactory from hibernate.cfg.xml              return new Configuration().configure().buildSessionFactory();          }          catch (Throwable ex) {              // Make sure you log the exception, as it might be swallowed              System.err.println("Initial SessionFactory creation failed." + ex);              throw new ExceptionInInitializerError(ex);          }      }        public static SessionFactory getSessionFactory() {          return sessionFactory;      }    }