通过JNDI获得一个用户事务

public class Trans {    private static Log log = LogFactory.getLog(Trans.class);    static {        log.debug("life Trans INITIAL_CONTEXT_FACTORY:"                + Env.TRANSACTION_INITIAL_CONTEXT_FACTORY);        log.debug("life Trans PROVIDER_URL:" + Env.TRANSACTION_PROVIDER_URL);        log.debug("life Trans SECURITY_PRINCIPAL:" + Env.PRINCIPAL);        log.debug("life Trans SECURITY_CREDENTIALS:" + Env.CREDENTIALS);    }    /**     * 通过JNDI获得一个用户事务句柄     * Last update      * date: 2005-05-11     * author: Zhangjr     *      * @return UserTransaction     */    public static UserTransaction getUserTransaction() throws NamingException,SystemException {        UserTransaction trans = null;        Context ctx = new InitialContext();        trans = (UserTransaction) ctx.lookup("java:comp/UserTransaction");        if (trans != null){            trans.setTransactionTimeout(60*20); // 设置事务超时间为25分钟            return new UserTransactionWrapper(trans);        }else{            return null;        }    }