1. function downloadFile($file){  
2. $file_name = $file;  
3. $mime = 'application/force-download';  
4. header('Pragma: public'); // required  
5. header('Expires: 0'); // no cache  
6. header('Cache-Control: must-revalidate, post-check=0, pre-check=0');  
7. header('Cache-Control: private',false);  
8. header('Content-Type: '.$mime);  
9. header('Content-Disposition: attachment; filename="'.basename($file_name).'"');  
10. header('Content-Transfer-Encoding: binary');  
11. header('Connection: close');  
12. readfile($file_name); // push it out  
13. exit();  
14. }  
15.  

原文链接：http://www.phpfensi.com/php/20140801/4113.html