PHP下载header

        $filestream=file_get_contents($filename);//读取文件

        header("Pragma: public");

        header("Expires: 0");

        header("Cache-Control: must-revalidate, post-check=0, pre-check=0");

        header("Content-Transfer-Encoding: binary");

        header("Content-Type:application/force-download");

        header("Accept-Ranges:bytes");

        header("Content-Lenght:". strlen($filestream));

        $filename=urlencode($filename);//ie下中文文件名乱码解决

        header("Content-Disposition:attachment;filename={$filename}");

        echo $filestream;