Header实现文件下载

 1 function download($file){
 2     //文件根路径
 3     $filename=$_SERVER[‘DOCUMENT_ROOT‘].__ROOT__.‘/‘.$file;
 4     //下载文件
 5     if(!file_exists($filename)){
 6         $this->error("找不到文件");
 7         exit;
 8     }else{
 9         header("Content-Type:text/html;charset=utf-8");
10         header("Content-type:application/force-download");
11         header("Content-Type:application/octet-stream");
13         header("Accept-Ranges:bytes");
14         header("Content-Length:".filesize($filename));//指定下载文件的大小
15         header(‘Content-Disposition:attachment;filename="‘.$file.‘"‘);
16         //必要时清除缓存
17         ob_clean();
18         flush();
19         readfile($filename);
20         exit();
21     }
22 }