jsp文件下载程序

文件下载程序
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');

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