Magento 2 stores the URL identifier in url_rewrite table. You can get the page entity_id or page_id by idendifier. If you look into url_rewrite table where you can search by request_path column.
Programmatically you can use the following Model Class.
/<Magento Root Directory>/vendor/magento/module-cms/Model/Page.php
protected $_page;
public function __construct(
...
\Magento\Cms\Model\Page $page,
...
) {
...
$this->_page = $page;
...
}
/**
* Check if page identifier exist for specific store return page id if page exists
*
* @param string $identifier
* @param int $storeId
* @return int
*/
$page_id = $this->_page->checkIdentifier('home', 0);
if ($page_id > 0) {
echo "Page Found with id : " . $page_id;
}else {
echo "Page Not Found";
}It will return 2 which is the default page id for home page.