url中文转码

<?php
$s = "\u4e2d\u56fd";
$s=str_replace("\\","%",$s);
function unescape($str) {
 $str = rawurldecode($str);
 preg_match_all("/(?:%u.{4})|.{4};|&#\d+;|.+/U",$str,$r);
 $ar = $r[0];
 #print_r($ar);
 foreach($ar as $k=>$v) {
 if(substr($v,0,2) == "%u")
 $ar[$k] = iconv("UCS-2","GB2312",pack("H4",substr($v,-4)));
 elseif(substr($v,0,3) == "")
 $ar[$k] = iconv("UCS-2","GB2312",pack("H4",substr($v,3,-1)));
 elseif(substr($v,0,2) == "&#") {
 echo substr($v,2,-1)."";
 $ar[$k] = iconv("UCS-2","GB2312",pack("n",substr($v,2,-1)));
 }
 }
 return join("",$ar);
}
echo unescape($s);
?>