PHP下载功能代码(2)

function wo_down($file_dir,$file_name){

  $file = @ fopen($file_dir . $file_name,"r");

    if (!$file) {

    echo "文件找不到";

    } else {

    header("content-type: application/octet-stream");

    header("content-disposition: attachment; filename=" . $file_name);

    while (!feof ($file)) {

    echo fread($file,50000);

    }

    fclose ($file);

    }

}