HibernateSessionFactory建立-使用ThreadLocal

package util;

import java.io.Serializable;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateSessionFactory implements Serializable{
    private static final String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";
    private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
    private  static Configuration configuration = new Configuration();    
    private static SessionFactory sessionFactory=null;
    private static String configFile = CONFIG_FILE_LOCATION;
    //static代码块只会在实例化类的时候只执行一次
    static{
        try {
            configuration.configure(configFile);
            sessionFactory = configuration.buildSessionFactory();
        } catch (Exception e) {
            System.err.println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
        
    }
    //获取Session
    public static Session getCurrentSession(){
        Session session =  threadLocal.get();
        //判断Session是否为空，如果为空，将创建一个session，并付给线程变量tLocalsess
        try {
            if(session ==null&&!session.isOpen()){
                if(sessionFactory==null){
                    rbuildSessionFactory();
                }else{
                    session = sessionFactory.openSession();
                }
                //session = (sessionFactory != null) ? sessionFactory.openSession(): null;
            }
            threadLocal.set(session);
        } catch (Exception e) {
            // TODO: handle exception
        }
        
        return session;
    }
    
    public static void rbuildSessionFactory(){
        try {
            configuration.configure(configFile);
            sessionFactory = configuration.buildSessionFactory();
        } catch (Exception e) {
            System.err.println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
    }
}