src/Controller.php
protected function setBack(string $url = ''): void
    {
        if (empty($url)) {
            $_SESSION['_BACK_URL'] = $this->request->url();
        } else {
            $_SESSION['_BACK_URL'] = $url;
        }
    }
protected function setBack(string $url = ''): void
    {
        if (empty($url)) {
            $_SESSION['_BACK_URL'] = $this->request->url();
        } else {
            $_SESSION['_BACK_URL'] = $url;
        }
    }
设置返回点URL,下次请求中可以使用getBack获取此URL
@param $url string 要设置的url