thinkphp上传文件大小

<?php
namespace app\index\controller;

use think\Controller;
use think\Request;

class Upload extends Controller
{
    public function index(Request $request)
    {
        if ($request->isPost()) {
            $file = $request->file('file');
            if ($file) {
                $info = $file->move(ROOT_PATH . 'public' . DS . 'uploads');
                if ($info) {
                    return '文件上传成功：' . $info->getSaveName();
                } else {
                    return '文件上传失败：' . $file->getError();
                }
            } else {
                return '没有选择文件';
            }
        }
        return view('upload');
    }
}

<!DOCTYPE html>
<html>
<head>
    <title>文件上传</title>
</head>
<body>
    <form action="/index/upload/index" method="post" enctype="multipart/form-data">
        <input type="file" name="file">
        <input type="submit" value="上传">
    </form>
</body>
</html>