dwr原理

    <h1 style="font-size: 150%;">direct web remoting</h1><h1 style="font-size: 150%;">dwr:web远程调用框架</h1> 
dwr is a java library that enables java on the server and javascript in a browser to interact and call each other as simply as possible.
dwr是一个java库，能够使服务器中java与浏览器中javascript相互影响并简单地互调。
 
dwr is easy ajax for java
dwr是简单的ajax，相对java而言。
 
dwr will generate the javascript to allow web browsers to securely call into java code almost as if it was running locally. it can marshal virtually any data including collections, pojos, xml and binary data like images and pdf files. all that is required is a security policy that defines what is allowed.
dwr会自动产生javascript，并允许网页浏览器安全地调用java代码，几乎就像本地运行一样。它几乎能够整理任何数据包括集合，pojo,xml和二进制数据如图片、pdf文件。所有这些必须的是一个安全策略，即定义了什么是允许的。
 
with reverse ajax, dwr allows java code running on a server to use client side apis to publish updates to arbitrary groups of browsers. this allows interaction 2 ways - browser calling server and server calling browser. dwr supports comet, polling and piggyback (sending data in with normal requests) as ways to publish to browsers.
利用反转ajax，dwr允许运行在服务器上java代码使用客户端api来发布对任意组浏览器的更新。这里有两种交互方式-
浏览器调用服务器和服务器调用浏览器。dwr支持comet（<span class="hl">comet</span> 是一种新的 web 应用架构）， polling and piggyback（用正常请求发送数据）这些方式发布到浏览器。
 
dwr provides integration with spring, struts, guice, hibernate and others.
dwr提供了与 spring, struts, guice, hibernate及其他的整合。