laravel file

<form action="/admin/post/store" method="post" enctype="multipart/form-data">
<input type="hidden" name="_method" value="post">
<button type="submit" class="btn btn-primary">发布</button>
</form>
if ($request->hasFile('nameFile'))
{
echo "aaa";
}

if ($request->file('nameFile')->isValid())
{
$clientName = $file -> getClientOriginalName();
$tmpName = $file ->getFileName();
$url = $file->getRealPath();

echo $url."<br>";
echo $clientName.'<br>';
echo $tmpName;

$file->move($url.'/uploads/',$clientName);
}

这都进不了 if 里面去 显示都是空白 什么也不输出
求各位 大虾 帮忙 看看

谢谢！加粗文字