php递归遍历目录下的文件

/** * 递归遍历目录下的文件 * @author gxk */$dir = "D:/files";if ($dh = opendir($dir)) {while (($file_name = readdir($dh)) !== FALSE) {echo $file_name . '</br>';}closedir($dh);}// 改进版function list_folder($dir){    if ($dh = opendir($dir)) {        while (($file_name = readdir($dh)) !== FALSE) {            if ($file_name != "." && $file_name != "..") {                if (is_dir($dir . "/" . $file_name)) {                    list_folder($dir . "/" . $file_name);                } else {                    echo $file_name.'</br>';                }            }        }        closedir($dh);    }list_folder($dir);