src/Leevel/Validate/Validator.php
protected function getFieldRuleMessage(string $field, string $rule): string
    {
        return $this->messages[$field.'.'.$rule] ?? $this->messages[$rule] ??
            static::$defaultMessages[$rule] ?? '';
    }
protected function getFieldRuleMessage(string $field, string $rule): string
    {
        return $this->messages[$field.'.'.$rule] ?? $this->messages[$rule] ??
            static::$defaultMessages[$rule] ?? '';
    }
获取验证消息.

@param string $field
@param string $rule

@return string