<?php
$filename = $_GET['filename'];
//从浏览器获取到的字符的编码是UTF-8，我们要用这个函数转换成GBK才能才本地找到这个文件
$filename = mb_convert_encoding($filename,'GBK','UTF-8');
echo $filename ."<br>";
if( empty($filename)){
    echo'<script> alert("非法连接 !"); location.replace ("index.php") </script>'; exit();
}

if   (!file_exists($filename))   {   //检查文件是否存在
    echo   "文件找不到";
    exit;
}   else   {
    $file = fopen($filename,"r"); // 打开文件
    // 输入文件标签
    Header("Content-type: application/octet-stream");
    Header("Accept-Ranges: bytes");
    Header("Accept-Length: ".filesize($filename));
    Header("Content-Disposition: attachment; filename=" . $filename);
    // 输出文件内容
    echo fread($file,filesize($filename));
    fclose($file);
    exit();
}
?>