EJB中使用Hibernate的方法以及常见问题

public class HibernateTestBean implements SessionBean ...{ 
    SessionContext sessionContext; 
    SessionFactory sf; 
    public void setSessionContext(SessionContext sessionContext) ...{ 
        this.sessionContext = sessionContext; 
        try ...{ 
            InitialContext ctx = new InitialContext(); 
            sf=(SessionFactory) ctx.lookup("java:/hibernate/SessionFactory"); 
        } catch (NamingException ex) ...{ 
            ex.printStackTrace(); 
        } 
    } 
    public void tran()...{ 
        tran1(); 
        tran2(); 
    } 
    public void tran1() ...{ 
        Session session=sf.getCurrentSession(); 
        Message msg=new Message(); 
        msg.setCreateTime(new Date()); 
        msg.setDetail("trans1"); 
        session.save(msg); 
        System.out.println("Session:"+session.hashCode()); 
        session.flush(); 
        session.close(); 
    } 
    public void tran2() ...{ 
      Session session=sf.getCurrentSession(); 
      Message msg=new Message(); 
      msg.setCreateTime(new Date()); 
      msg.setDetail("trans2"); 
      session.save(msg); 
       System.out.println("Session:"+session.hashCode()); 
 //  throw new RuntimeException("wrong"); 
  } 
…… 
}