session数据存取的方法可通过session.serialize_handler方法来判断，反序列化可通过下面的unserialize方法，参考http://stackoverflow.com/questions/27813619/unserializing-php-session-data-from-db-table

public static function unserialize($session_data) {    $method = ini_get("session.serialize_handler");    switch ($method) {        case "php":            return self::unserialize_php($session_data);            break;        case "php_binary":            return self::unserialize_phpbinary($session_data);            break;        default:            throw new Exception("Unsupported session.serialize_handler: " . $method . ". Supported: php, php_binary");    }}

private static function unserialize_php($session_data) {    $return_data = array();    $offset = 0;    while ($offset < strlen($session_data)) {        if (!strstr(substr($session_data, $offset), "|")) {            throw new Exception("invalid data, remaining: " . substr($session_data, $offset));        }        $pos = strpos($session_data, "|", $offset);        $num = $pos - $offset;        $varname = substr($session_data, $offset, $num);        $offset += $num + 1;        $data = unserialize(substr($session_data, $offset));        $return_data[$varname] = $data;        $offset += strlen(serialize($data));    }    return $return_data;}

private static function unserialize_phpbinary($session_data) {    $return_data = array();    $offset = 0;    while ($offset < strlen($session_data)) {        $num = ord($session_data[$offset]);        $offset += 1;        $varname = substr($session_data, $offset, $num);        $offset += $num;        $data = unserialize(substr($session_data, $offset));        $return_data[$varname] = $data;        $offset += strlen(serialize($data));    }    return $return_data;}