PHP PDF文件上传

/**
* 上传PDF文件
*/
function UploadPdf(){
if(is_array($_FILES)){
$tmp_file = $_FILES['pdf'] ['tmp_name'][$i];
$file_types = explode ( ".", $_FILES['pdf'] ['name'][$i] );
$file_type = $file_types [count ( $file_types ) - 1];
$savePath = "pdfupload/";
$file_name = 'pdf_' . '_'.date ( 'ymdhis' ). $i . "." . $file_type;
if(!file_exists($savePath)){
mkdir($savePath,0777,true);
}
move_uploaded_file($_FILES['pdf']['tmp_name'][$i], $savePath.$file_name);
return $savePath.$file_name;
}
}