php readfile下载大文件失败怎么办

大文件有200多M，只下载了200K就提示下载完成，且不报错。

原因是PHP内存有限制，需要改为按块下载，就是把大文件切块后逐块下载。

if (file_exists($file)) { if (FALSE!==($handler=fopen($file, 'r'))) { header('Content-Description: File Transfer'); header('Content-Type: application/octet-stream'); header('Content-Disposition: attachment; filename='.basename($file)); header('Content-Transfer-Encoding: chunked'); //changed to chunked header('Expires: 0'); header('Cache-Control: must-revalidate, post-check=0, pre-check=0'); header('Pragma: public'); //header('Content-Length: ' . filesize($file)); //Remove //Send the content in chunks while(false !==($chunk=fread($handler,4096))) { echo $chunk; } } exit; } echo "<h1>Content error</h1><p>The file does not exist!</p>";