php-文件下载

/** * 文件下载 * @param $filepath 文件路径 * @param $filename 文件名称 */function file_down($filepath, $filename = '') {   if(!$filename) $filename = basename($filepath);   if(is_ie()) $filename = rawurlencode($filename);   $filetype = fileext($filename);   $filesize = sprintf("%u", filesize($filepath));   if(ob_get_length() !== false) @ob_end_clean();   header('Pragma: public');   header('Last-Modified: '.gmdate('D, d M Y H:i:s') . ' GMT');   header('Cache-Control: no-store, no-cache, must-revalidate');   header('Cache-Control: pre-check=0, post-check=0, max-age=0');   header('Content-Transfer-Encoding: binary');   header('Content-Encoding: none');   header('Content-type: '.$filetype);   header('Content-Disposition: attachment; filename="'.$filename.'"');   header('Content-length: '.$filesize);   readfile($filepath);   exit;}