package com.joe.hibernatesessionfactory;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateSessionFactory {
	//指定要读取配置文件路径
    private static String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";
    //实例化ThreadLocal类
	private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
	//实例化Configuration类
    private  static Configuration configuration = new Configuration();  
    //声明SessionFactory接口
    private static SessionFactory sessionFactory;
    //定义configFile变量并赋值
    private static String configFile = CONFIG_FILE_LOCATION;

	static {
    	try {
    		//读取默认的配置文件hibernate.cfg.xml
			configuration.configure(configFile);
			//实例化SessionFactory
			sessionFactory = configuration.buildSessionFactory();
		} catch (Exception e) {
			e.printStackTrace();
		}
    }
    private HibernateSessionFactory() { }//创建无参的HibernateSessionFactory构造函数
    //获取Session
    public static Session getSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        //判断是否已经存在Session对象
		if (session == null || !session.isOpen()) {
			//如果SessionFactory对象为null，则创建SessionFactory
			if (sessionFactory == null) {
				rebuildSessionFactory();//调用rebuildSessionFactory方法创建SessionFactory
			}
			//判断SessionFactory对象是否为null，如果不是，则打开Session
			session = (sessionFactory != null) ? sessionFactory.openSession()
					: null;
			threadLocal.set(session);
		}

        return session;
    }
    //创建SessionFactory
	public static void rebuildSessionFactory() {
		try {
			configuration.configure(configFile);
			sessionFactory = configuration.buildSessionFactory();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	//关闭Session
    public static void closeSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        threadLocal.set(null);
        if (session != null) {
            session.close();
        }
    }
    //SessionFactory对象的getXXX()方法
	public static SessionFactory getSessionFactory() {
		return sessionFactory;
	}
	//configFile属性的setXXX()方法
	public static void setConfigFile(String configFile) {
		HibernateSessionFactory.configFile = configFile;
		sessionFactory = null;
	}
	//configFile属性的getXXX()方法
	public static Configuration getConfiguration() {
		return configuration;
	}
	public static void main(String[] args){
		Session session=HibernateSessionFactory.getSession();
		session.beginTransaction();
		System.out.println("陈宫");
	}

}