JSF2.0 Tomcat7中@Named和@ManagedBean注解的区别 [英] Difference between @Named and @ManagedBean annotations in JSF2.0 Tomcat7

问题描述

这可能是一个菜鸟问题，但是在很多教程和示例中，我看到使用这些注释就好像它们做同样的事情一样.

This might be a noob question, however in a lot of tutorials and examples I saw these annotations used as if they did the same thing.

但是我在使用 @Named 时遇到了一些限制(特别是依赖注入等)我找不到解释差异的来源，如果有人我会非常感谢可以粗略地概述何时使用其中一个.

However I ran into some limitations using the @Named one (especially with dependency injection etc.) I couldn't find a source where the difference is explained and I'd be very thankful if someone can give a rough overview on when to use one or the other.

推荐答案

@Named 为 CDI 托管 bean 提供了一个 EL 名称，以便在 JSF 或 JSP 等视图技术中使用.请注意，在 CDI 应用程序中，您不需要需要 @Named 注释来创建由 CDI 管理的 bean(感谢 @Karl 的评论).

@Named gives a CDI managed bean an EL name to be used in view technologies like JSF or JSP. Note that in a CDI application you don't need the @Named annotation to make a bean managed by CDI (thanks to @Karl for his comment).

@ManagedBean 使 bean 由 JSF 管理，您可以:

@ManagedBean makes the bean managed by JSF and you can:

• 将其注入其他@ManagedBean 注释的bean(但不注入@Named bean！)
• 通过表达语言从您的观点访问它

请参阅此相关问题了解更多信息两种 bean 之间的注入是如何工作的.

See this related question for further information how injection works among both kind of beans.

请注意，bean 的范围也有所不同.它们来自不同的包但名称相同(JSF:javax.faces.bean，CDI:javax.enterprise.context，因此它通常是错误和混淆的来源如果您包含错误的类.

Note that there is also a difference with the scope of the beans. They come from different packages but are named identically (JSF: javax.faces.bean, CDI: javax.enterprise.context , so it is often a source of error and confusion if you include the wrong class.

根据我的经验:您应该尽可能使用 CDI bean，因为它们比 JSF 托管 bean 更灵活. 唯一的缺点是 CDI 不知道视图范围，因此您要么需要回退到@ManagedBean，要么使用一些第三方扩展，如 Seam.

From my experience: You should use CDI beans whenever possible since they are more flexible than JSF managed beans. Only drawback is that CDI doesn't know a view scope, so you either need to fall back to @ManagedBean or use some third party extension like Seam.

CDI 支持 ViewScope，更多信息关于 链接

CDI supports ViewScope, more info on LINK

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