java自定义动态链接数据库示例

package dao;

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

/**
 * @author minxuenetcn
 */
public class HibernateSessionFactory {  

    private final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();  
    private Configuration configuration = new Configuration();   
    private org.hibernate.SessionFactory sessionFactory;  

    /**
     * hibernate.cfg.xml
     * @param configFile
     */
    public void setConfiguration(String configFile){
     this.configuration=new Configuration();
     configuration.configure(configFile);

    }  
    /** 
     * Returns the ThreadLocal Session instance. 
     *  @return Session 
     *  @throws HibernateException
     */  
    public 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;  
    }  
    /** 
     *  Rebuild hibernate session factory 
     * 
     */  
    public void rebuildSessionFactory() {   

     try {  
            sessionFactory = this.configuration.buildSessionFactory();  
        } catch (Exception e) {  
            System.err  
                    .println("%%%% Error Creating SessionFactory %%%%");  
            e.printStackTrace();  
        }  
    }  

    /** 
     *  Close the single hibernate session instance. 
     * 
     *  @throws HibernateException 
     */  
    public void closeSession() throws HibernateException {  
        Session session = (Session) threadLocal.get();  
        threadLocal.set(null);  
        if (session != null) {  
            session.close();  
        }  
    }  
    /** 
     *  return session factory 
     * 
     */  
    public org.hibernate.SessionFactory getSessionFactory() {  
        return sessionFactory;  
    }  
    /** 
     *  return hibernate configuration 
     */  
    public Configuration getConfiguration() {  
        return configuration;  
    }  
}