php 字典升序从小到大方法

 /*  字典升序*/
    function formatParaMap($paraMap)
    {
        $buff = "";
        ksort($paraMap);
        foreach ($paraMap as $k => $v)
        {
            $buff .= $k . "=" . $v . "&";
        }
        $reqPar = '';  //去掉最后一个字符 $
        if (strlen($buff) > 0)
        {
            $reqPar = substr($buff, 0, strlen($buff)-1);
        }
        return $reqPar;
    }