EJBFactory4

public EJBHome getHome(String jndiName, Class ejbHome) throws Exception
    {
       
        EJBHome home = null;
        try
        {
            home = (EJBHome)homeMap.get(jndiName); //如果map中已存在该EJBHome类型的实例，直接取得
            if (home == null)
            { //如果map中不存在该EJBHome类型的实例，产生一个实例，并存储到map里
           
                getInitialContext();
                //look up jndi name
                Object ref = initContext.lookup(jndiName);
                //look up jndi name and cast to Home interface
               
                home = (EJBHome)PortableRemoteObject.narrow(ref, ejbHome);
               
                homeMap.put(jndiName, home);
            }
        }
        catch (NamingException e)
        {
            //此处不能直接调用Message，容易引起堆栈溢出。
            e.printStackTrace();
            throw new Exception(e);
        }
       
        return home;
    }