php 不能写汉字吗

header("Content-type:text/html; charset=utf-8");

<?php
header("Content-type:text/html; charset=utf-8");
$dirname = $_GET['dirname'];
echo $dirname.'<br />';
//必须要转换成GBK
$dirname = iconv('utf-8', 'GBK', $dirname);
echo $dirname.'<br />';
?>

<?php
header("Content-type:text/html; charset=utf-8");
$dirname = $_GET['dirname'];
$dirname = iconv('utf-8', 'GBK', $dirname);
function read_all ($dir){
    if(!is_dir($dir)) return false;
    $handle = opendir($dir);
    if($handle){
        while(($fl = readdir($handle)) != false){
            $temp = $dir.DIRECTORY_SEPARATOR.$fl;
            if(is_dir($temp) && $fl!='.' && $fl != '..'){
                read_all($temp);
            }else{
                if($fl!='.' && $fl != '..'){
                    $temp = iconv('GBK', 'utf-8', $temp); //再将GBK编码转换为utf-8编码
                    echo $temp.'<br>';
                }
            }
        }
    }
}
read_all($dirname);
?>