require('UploadHandler.PHP');
class CustomUploadHandler extends UploadHandler {
    protected function trim_file_name($file_path,$name,$size,$type,$error,$index,$content_range) {
            $name = 'First_' . microtime(true);
            $name = str_replace('.','',$name);
            return $name;
        }
}

$upload_handler = new CustomUploadHandler();

在您的自定义文件中,index.PHP初始化UploadHandler.PHP的这个函数