Vaadin 是一个RIA的基于浏览器的富客户端的Web框架。与 JavaScript 库或者是基于浏览器插件的解决方案不同，Vaadin 包含一个服务器端的结构，主要的应用逻辑都在服务器端运行，浏览器通过 Ajax 技术跟服务器端进行交互。Vaadin 提供多种各样的UI组建，例如按钮、表格、树形列表等等，每个组件都具有事件、侦听器、数据绑定和业务逻辑等功能。
Vaadin 发布 7.0 的第 5 个 Beta 版本，该版本包含众多改进记录，主要内容如下：
GWT is now built into Vaadin Framework
New SuperDevMode allows debugging client-side Java code in the browser without any plugins
Navigation API for view navigation
View navigation with bookmarking/linking with URI fragments and browser history support
Access control for views, view change confirmation
Component and UI extensions
Resource loading (JS/CSS) by the framework
Complete overhaul of the client-server communication architecture
All add-on components that have widgets need to be ported to Vaadin 7
Integration of a GWT widget is done in a connector class
Component-to-widget mapping now defined on the client-side, in the connector
No more Paintable or VariableOwner
Server-side component and client-side widget can have a shared state object which is automatically synchronized
Both client-side and server-side can make RPC calls to the other side
Communicated in the next request/response
No return values
Typically for communicating events
Support for JavaScript components - GWT integration code not required
Handle JavaScript callbacks on the server-side
UIDL is deprecated
Compatibility layer for Vaadin 6 included for easy migration
Form is deprecated and form hand is replaced with the FieldGroup
Get computed style of a component from the browser
Support for border, padding, and margin in core layout components
Applications are now written by extending the UI class
UIs use heartbeat to detect closing
The Application class is removed altogether
ApplicationServlet is replaced with VaadinServlet
ApplicationResource is replaced with ConnectorResource
Themeing with SASS in addition to CSS
SASS themes need to (and CSS themes can) be compiled to a single CSS stylesheet with the vaadin-theme-compiler
Add-ons can modify the startup page
All addListener() methods have changed to listener-specific methods, such as addClickListener(), addValueChangeListener(), etc.
Packaging has changed, now in a ZIP package (see Package Contents above)
更多关于 Vaadin 7 的介绍可看https://vaadin.com/download/prerelease/7.0/7.0.0/7.0.0.beta5/release-notes.html
主页：https://vaadin.com/home
下载：https://vaadin.com/download
来自:开源中国社区
