class DBAccess extends PDO{    private $charset;    // 数据库字符集

public $cacheDir='_cache_$98sdf29@fw!d#s4fef/';    public $prename;    public $time;    function __construct($dsn, $user='', $password=''){        try{            parent::__construct($dsn, $user, $password);

}catch(Exception $e){//            throw new Exception('连接数据库失败');//            throw new Exception($e->getMessage());//            print_r($user);

print_r($dsn);

print_r($e->getMessage());

}        $this->time=intval($_SERVER['REQUEST_TIME']);

}

}

host自动被替换了，这是怎么回事？？