public function __construct($options = array())
{
$this->options['expire'] = isset($options['expire']) ? $options['expire'] : C('DATA_CACHE_TIME');
$this->options['prefix'] = isset($options['prefix']) ? $options['prefix'] : C('DATA_CACHE_PREFIX');
$this->options['length'] = isset($options['length']) ? $options['length'] : 0;
}