在Vaadin中，有很多不同的身份验证方法.

There are a lot of different ways for authentication in Vaadin.

1. Vaadin基本身份验证.
   • 对于Vaadin 6，请尝试 LoginForm .
   • 对于Vaadin 7，您可以使用新的&改进了LoginForm的替换实现，首先是可作为附件使用，然后是内置于Vaadin 7.7中.
   • 对于Vaadin 8，使用相同的重新实现的 LoginForm .
   • 对于 Vaadin Flow (自版本12开始未实现).您可以细读开源代码并进行构建相似的东西.超类内置了对侦听器"的支持，因此您无需从头开始.

1. Vaadin base authentication.
   • For Vaadin 6, try LoginForm.
   • For Vaadin 7, you can use the new & improved replacement implementation of LoginForm first available as a Add-On, then later built into Vaadin 7.7.
   • For Vaadin 8, use that same re-implemented LoginForm.
   • For Vaadin Flow, not implemented as of version 12. You could peruse the open source code, and build something similar. The "Listener" support is built into the superclasses, so you are not starting from scratch.

如果要简化操作，我建议选择1或2，如果需要电源安全系统，则选择4.

I recommend you to select 1 or 2 if you want make it easy or 4 if you want power security system.