blocks|key|3250626|text|AJAXed|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3250627|在我看来，Spring+MVC是构建AJAXed/COMETed+RIA的一个非常糟糕的选择。ModelAndView组件旨在处理HTML表单并一次呈现整个页面，标记库、验证例程都更适合于基于JSP和模板的老式开发。对我来说，将AJAX/COMET插入Spring+MVC永远是一种技巧。但是，如果您打算使用@MVC+(与javascript+UI互换JSON+)构建RESTful服务，它可能会起作用(尽管我更喜欢Jersey/JAXB+)。|unordered-list-item|3250628|
|3250629|LIFT最初是为使用COMET而设计的，因此它将是一个更好的选择。虽然我会选择比LIFT更轻量级和更少模板的东西(对我来说，它和Spring+MVC有同样的问题)。|3250630|3250631|这两个安全系统只涵盖了基本的场景，并且需要在现实世界的项目中使用很多定制。|3250632|3250633|这就是我在COMETed中构建Scala+RIA时要用到的：|3250634|-+[Jersey](http://jersey.java.net/)+(lightweight+RESTful+services+to+communicate+with+JS+UI+over+HTTP/JSON)+%2B+[Atmosphere](https://atmosphere.dev.java.net/)+(scalable+solution+for+building+COMETed+applications)+%2B+any+JS+framework+(jquery,+YUI,+ext+js,+...).+You+should+also+have+a+look+at+[Akka+Framework](http://doc.akkasource.org/),+which+is+integrated+with+the+both+Jersey+and+Atmosphere,+and+allows+you+building+RIA+web-apps+in+idiomatic+Scala.+Here's+a+[pub-sub+COMET+example](http://doc.akkasource.org/comet)+in+Akka.
-+[Vaadin](http://vaadin.com/home)+%2B+[ICEPush](http://vaadin.com/directory#addon/icepush).+It+will+be+much+comfortable+combination+for+you,+if+you+don't+want+to+get+your+hand+dirty+with+JS+(though+ICEpush+is+not+an+enterprise-ready+solution+yet).+++|code-block|syntax|javascript|3250635|​|3250636|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Y|8|@]|9|@]|A|$]]|$1|E|3|F|5|6|7|Z|8|@]|9|@]|A|$]]|$1|G|3|H|5|D|7|10|8|@]|9|@]|A|$]]|$1|I|3|F|5|6|7|11|8|@]|9|@]|A|$]]|$1|J|3|K|5|D|7|12|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|13|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|14|8|@]|9|@]|A|$]]|$1|O|3|P|5|Q|7|15|8|@]|9|@]|A|$R|S]]|$1|T|3|U|5|6|7|16|8|@]|9|@]|A|$]]|$1|V|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|W|$]]

<ol>
<li>From my point of view, Spring MVC is a very bad choice to build AJAXed/COMETed RIA. ModelAndView component aimed to work with HTML forms and render the entire page at once, tag libraries, validation routines are all better suited for old-fashioned development, based on JSPs and templates. For me, plugging AJAX/COMET into Spring MVC will always be a kind of a hack. However, if you're going to build RESTful services using @MVC (interchanging JSON with your javascript UI), it may work (though I would prefer Jersey/JAXB for those matters). </li>
<li>LIFT was originally designed to work with COMET, so it will be a better choice. Though I would choose something much more lightweight and template-less, than LIFT (as for me, it suffers from the same disease Spring MVC does).</li>
<li>The both security systems cover just basic scenarios, and require a lot of customization to be used in real-world projects.
 
That's what I would use for building COMETed RIA in Scala:

<ul>
<li><a href="http://jersey.java.net/" rel="nofollow noreferrer">Jersey</a> (lightweight RESTful services to communicate with JS UI over HTTP/JSON) + <a href="https://atmosphere.dev.java.net/" rel="nofollow noreferrer">Atmosphere</a> (scalable solution for building COMETed applications) + any JS framework (jquery, YUI, ext js, ...). You should also have a look at <a href="http://doc.akkasource.org/" rel="nofollow noreferrer">Akka Framework</a>, which is integrated with the both Jersey and Atmosphere, and allows you building RIA web-apps in idiomatic Scala. Here's a <a href="http://doc.akkasource.org/comet" rel="nofollow noreferrer">pub-sub COMET example</a> in Akka.</li>
<li><a href="http://vaadin.com/home" rel="nofollow noreferrer">Vaadin</a> + <a href="http://vaadin.com/directory#addon/icepush" rel="nofollow noreferrer">ICEPush</a>. It will be much comfortable combination for you, if you don't want to get your hand dirty with JS (though ICEpush is not an enterprise-ready solution yet). </li>
</ul></li>
</ol>

blocks|key|304091|text|Lift的Comet架构，Novell在评估了许多不同的技术后，选择它来驱动他们的Pulse产品。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|304092|Lift的Comet实现使用单个HTTP连接来轮询页面上任意数量的组件的更改。每个组件都有一个版本号。长轮询包括版本号和组件GUID。在服务器端，监听程序附加到长轮询请求中列出的所有GUID。如果任何组件具有更高的版本号(或者版本号在长轮询期间增加)，则增量(描述每个版本的更改的一组JavaScript+)被发送到客户端。将应用增量，并将客户端上的版本号设置为变更集的最高版本号。|304093|Lift将长轮询与会话管理集成在一起，因此，如果在长轮询期间请求进入同一URL，会导致连接匮乏，长轮询将被终止以避免连接匮乏(某些浏览器在每个命名服务器上最多有2个HTTP连接，而其他浏览器最多有6个)。Lift还支持针对长轮询请求的DNS通配符服务器，以便浏览器中的每个选项卡可以针对不同的DNS通配符服务器执行长轮询。这避免了连接匮乏问题。|304094|Lift动态检测运行Servlet的容器，Jetty+6&7和Glassfish+(很快)，Lift将使用平台的"continuations“实现，以避免在长轮询期间使用线程。|304095|Lift的JavaScript可以位于jQuery和YUI之上(也可以位于Prototype/+sit之上)。实际的轮询代码包括连接失败时的退避和其他处理瞬时连接失败的“优雅”方法。|304096|我看过Atmosphere、CometD、Akka+(所有面向JVM虚拟机的Comet技术)。没有一个(在我评估它们的时候)支持每页多个组件或避免连接匮乏。|304097|Novell从零开始，出于一些非常好的原因选择了Lift+to+power+Pulse。|304098|在安全性方面，Lift轻松击败了Spring+%2B+Spring+security。请参阅http://www.mail-archive.com/liftweb@googlegroups.com/msg13020.html|offset|length|304099|基本上，Lift的安全性已经包含在您的应用程序中。默认情况下，Lift应用程序可以抵抗常见问题(跨站点脚本、重放攻击、跨站点请求伪造)。默认情况下，Lift应用程序可以防止参数篡改。Lift的sitemap定义了站点导航和访问控制规则。这意味着你永远不会有别人不能点击的链接。你不需要有一个外部过滤器(例如，Spring+Security)，你必须独立于你的应用程序进行配置(哇...移动了一个页面，但忘记了确保Spring+Security+XML文件已更新。)|304100|哦..。如果你不想使用模板语言，这里有一个完整的Lift+Comet聊天组件：|304101|class+Chat+extends+CometActor+with+CometListener+{
++private+var+msgs:+List[String]+=+Nil

++def+registerWith+=+ChatServer

++override+def+lowPriority+=+{
++++case+m:+List[String]+=>+msgs+=+m;+reRender(false)
++}

++def+render+=+{
++++<div>
++++<ul>
++++{
++++++msgs.reverse.map(m+=>+<li>{m}</li>)
++++}
++++</ul>
++++<lift:form>
++++{
++++++SHtml.text("",+s+=>+ChatServer+!+s)
++++}
++++<input+type="submit"+value="Chat"/>
++++</lift:form>
++++</div>
++}
}|code-block|syntax|javascript|304102|并将此代码插入到页面中：<lift:comet+type="Chat"/>|style|CODE|304103|entityMap|0|LINK|mutability|MUTABLE|url|http://www.mail-archive.com/liftweb@googlegroups.com/msg13020.html^0|0|0|0|0|0|0|0|18|1U|0|0|0|0|0|C|P|0^^$0|@$1|2|3|4|5|6|7|1C|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1D|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|1E|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|1F|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|1G|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|1H|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|1I|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|1J|8|@]|9|@$P|1K|Q|1L|1|1M]]|A|$]]|$1|R|3|S|5|6|7|1N|8|@]|9|@]|A|$]]|$1|T|3|U|5|6|7|1O|8|@]|9|@]|A|$]]|$1|V|3|W|5|X|7|1P|8|@]|9|@]|A|$Y|Z]]|$1|10|3|11|5|6|7|1Q|8|@$P|1R|Q|1S|12|13]]|9|@]|A|$]]|$1|14|3|-4|5|6|7|1T|8|@]|9|@]|A|$]]]|15|$16|$5|17|18|19|A|$1A|1B]]]]

Lift's Comet Architecture which was selected by Novell to power their Pulse product after they evaluated a number of different technologies.

Lift's Comet implementation uses a single HTTP connection to poll for changes to an arbitrary number of components on the page. Each component has a version number. The long poll includes the version number and the component GUID. On the server side, a listener is attached to all of the GUIDs listed in the long poll requests. If any of the components has a higher version number (or the version number increases during the period of the long poll), the deltas (a set of JavaScript describing the change from each version) is sent to the client. The deltas are applied and the version number on the client is set to the highest version number for the change set.

Lift integrates long polling with session management so that if a request comes into the same URL during a long poll that would cause connection starvation, the long poll is terminated to avoid connection starvation (some browsers have a maximum of 2 HTTP connections per named server, others have a max of 6). Lift also supports DNS wild-carded servers for long poll requests such that each tab in the browser can do long polling against a different DNS wildcarded server. This avoids the connection starvation issues.

Lift dynamically detects the container the Servlet is running in and on Jetty 6 &amp; 7 and (soon) Glassfish, Lift will use the platform's "continuations" implementation to avoid using a thread during the long poll.

Lift's JavaScript can sit on top of jQuery and YUI (and could sit on top of Prototype/Scriptaculous as well.) The actual polling code includes back-off on connection failures and other "graceful" ways of dealing with transient connection failures.

I've looked at Atmosphere, CometD, Akka (all JVM-oriented Comet technologies). None had (at the time I evaluated them) support for multiple components per page or connection starvation avoidance.

Novell started from scratch and chose Lift to power Pulse for some very good reasons.

In terms of security, Lift beats Spring + Spring Security hands down. See <a href="http://www.mail-archive.com/liftweb@googlegroups.com/msg13020.html" rel="nofollow noreferrer">http://www.mail-archive.com/liftweb@googlegroups.com/msg13020.html</a>

Basically, Lift's security is baked into your application. Lift apps are resistant to common problems (cross site scripting, replay attacks, cross site request forgeries) by default. Lift apps are resistant to parameter tampering by default. Lift's sitemap defines site navigation and access control rules. This means you never have a link that someone can't click on. You don't need to have an external filter (e.g., Spring Security) that you have to configure independently from you app (whoops... moved a page, but forgot to make sure the Spring Security XML file was updated.)

Oh... and if you don't want to use a templating language, here's a complete Lift Comet chat component:

<pre><code>class Chat extends CometActor with CometListener {
 private var msgs: List[String] = Nil

 def registerWith = ChatServer

 override def lowPriority = {
 case m: List[String] =&gt; msgs = m; reRender(false)
 }

 def render = {
 &lt;div&gt;
 &lt;ul&gt;
 {
 msgs.reverse.map(m =&gt; &lt;li&gt;{m}&lt;/li&gt;)
 }
 &lt;/ul&gt;
 &lt;lift:form&gt;
 {
 SHtml.text("", s =&gt; ChatServer ! s)
 }
 &lt;input type="submit" value="Chat"/&gt;
 &lt;/lift:form&gt;
 &lt;/div&gt;
 }
}
</code></pre>

And to insert this into a page: <code>&lt;lift:comet type="Chat"/&gt;</code>

blocks|key|3250706|text|另一种选择是以纯Java+(或任何其他JVM语言，包括Scala)为中心的ItsNat+Comet。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3250707|entityMap|0|LINK|mutability|MUTABLE|url|http://www.innowhere.com:8080/itsnat/feashow_servlet?itsnat_doc_name=feashow.main&feature=feashow.core.listeners.cometNotifier.default^0|11|C|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Another alternative, pure Java (or with any other JVM language including Scala) centric is <a href="http://www.innowhere.com:8080/itsnat/feashow_servlet?itsnat_doc_name=feashow.main&amp;feature=feashow.core.listeners.cometNotifier.default" rel="nofollow">ItsNat Comet</a>.

There is a <a href="http://www.ibm.com/developerworks/java/library/j-jettydwr/index.html" rel="noreferrer">demo by IBM</a> that shows how easy Reverse AJAX can be used with DWR 2. On the other hand, Scala/LIFT comes with built-in Reverse AJAX capability. 

<ol>
<li>Question: Any experience if this works fine with Spring MVC?</li>
<li>Question: If you'd start from scratch, what are the pros and cons for preferring Scala/LIFT over DWR/Spring MVC</li>
<li>Question: In Scala/LIFT, is the security handling as sophisticated as in Spring Security?</li>
</ol>

Reverse AJAX (Comet) and Spring MVC vs. Scala/LIFT?

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有一个展示了在DWR2中使用反向AJAX是多么容易。另一方面，Scala/LIFT带有内置的反向AJAX功能。问题:如果这在Spring MVC中工作得很好，有什么经验吗？问题:如果你想从头开始，选择Scala/LIFT而不是DWR/Spring MVC问题:在Scala/LIFT中，安全处理是否像Spring sec...

问Reverse AJAX (Comet)和Spring MVC与Scala/LIFT？
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