use Encode qw[decode];

use Encode qw[decode]
 
$a = "星期一";
$a = decode("gbk",$a,1);
 
$len = length $a;
$out = "";
for($i=0;$i<$len;$i++){
         $c = substr($a,$i,1);
         $out .= sprintf("%%u%x",ord $c);
}
print $out;