thinkphp-butter/app/validate/UserLogin.php

<?php

namespace app\validate;

use think\Validate;

class UserLogin extends Validate
{
    protected $rule =   [
        'username'  => 'require',
        'password'   => 'require',

    ];

    protected $message  =   [
        'username.require' => '登录名称不能为空',
        'password.require'     => '登录密码不能为空',

    ];
}