我根据以下 URL 说明在 magento 中创建了名为 helloworld 的模块
http://magento4u.wordpress.com/2009/06/08/create-new-module-helloworld-in-magento/
一旦创建了我可以在管理页面中启用模块的所有内容。但是当我在浏览器中输入以下 URL 时，它会抛出 404 Not found
http://localhost/magento/magento3/index.php/helloworld/
提前致谢。请帮忙
As you already mentioned, you simply forgot to clear the cache, so Magento did not recognize your extension.
If you run into this issue again, you should also have a look at your ACL definitions. If you have none, your admin user is probably not allowed to use your extension in this case you need to define a ACL rule. Check Mage_Adminhtml_System_ConfigController::_isSectionAllowed() for details.