在filter中關閉session

原文：http://www.javaworld.com.tw/confluence/pages/viewpage.action?pageId=805

利用Thread-Specific Storage撰寫一個HibernateUtil

HibernateSessionUtil.java

import java.io.Serializable;import net.sf.hibernate.HibernateException;import net.sf.hibernate.Session;import net.sf.hibernate.SessionFactory;import net.sf.hibernate.Transaction;public class HibernateSessionUtil implements Serializable{    public static final ThreadLocal tLocalsess = new ThreadLocal();    public static final ThreadLocal tLocaltx = new ThreadLocal();    /*     * getting the thread-safe session for using     */    public static Session currentSession(){        Session session = (Session) tLocalsess.get();        //open a new one, if none can be found.        try{            if (session == null){                session = openSession();                tLocalsess.set(session);            }        }catch (HibernateException e){            throw new InfrastructureException(e);        }        return session;    }    /*     * closing the thread-safe session     */    public static void closeSession(){        Session session = (Session) tLocalsess.get();        tLocalsess.set(null);        try{            if (session != null && session.isOpen()){                session.close();            }        }catch (HibernateException e){            throw new InfrastructureException(e);        }    }    /*     * begin the transaction     */    public static void beginTransaction(){        Transaction tx = (Transaction) tLocaltx.get();        try{            if (tx == null){                tx = currentSession().beginTransaction();                tLocaltx.set(tx);            }        }catch (HibernateException e){            throw new InfrastructureException(e);        }    }    /*     * close the transaction     */    public static void commitTransaction(){        Transaction tx = (Transaction) tLocaltx.get();        try{            if (tx != null && !tx.wasCommitted() && !tx.wasRolledBack())                tx.commit();            tLocaltx.set(null);        }catch (HibernateException e){            throw new InfrastructureException(e);        }    }    /*     * for rollbacking     */    public static void rollbackTransaction(){        Transaction tx = (Transaction) tLocaltx.get();        try{            tLocaltx.set(null);            if (tx != null && !tx.wasCommitted() && !tx.wasRolledBack()){                tx.rollback();            }        }catch (HibernateException e){            throw new InfrastructureException(e);        }    }    private static Session openSession() throws HibernateException{        return getSessionFactory().openSession();    }    private static SessionFactory getSessionFactory() throws HibernateException{        return SingletonSessionFactory.getInstance();    }}

　filter中的程式碼如下

HibernateSessionCloser.java

public class HibernateSessionCloser implements Filter{    protected FilterConfig filterConfig = null;    public void init(FilterConfig filterConfig)throws ServletException{this.filterConfig = filterConfig;    }        public void destroy(){        this.filterConfig = null;    }        public void doFilter(ServletRequest request, ServletResponse response,                         FilterChain chain)throws IOException, ServletException {        try{            chain.doFilter(request, response);        }        finally{            try{                HibernateSessionUtil.commitTransaction();            }catch (InfrastructureException e){                HibernateSessionUtil.rollbackTransaction();            }finally{                HibernateSessionUtil.closeSession();            }           }    }}

然後在操作資料庫之前加上

HibernateSessionUtil.beginTransaction();HibernateSessionUtil.currentSession();//取得Session