test/app/Http/Requests/InvoiceSaveRequest.php

<?php

namespace App\Http\Requests;

class InvoiceSaveRequest extends Request
{
    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()
    {
        return true;
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        if (!$this->ajax()) {
            return [];
        }

        return [
            'amount' => 'required',
            'title' => 'required',
            'tax_no' => 'required'
        ];
    }


    public function attributes()
    {
        return [
            'amount' => '金额',
            'title' => '标题',
            'tax_no' => '税号'
        ];
    }
}