java什么是JSF ManagedBean？它在三层clientserver框架中扮演什么角色？

Question

我已经找到了下面的内容，但我似乎无法找到它在三层客户机-服务器框架中扮演的角色。 我们有浏览器、网络服务器和数据库。数据库和Web服务器由JDBC层链接，但我看不到任何关于托管bean在哪里发挥作用的信息

我假设它将信息输入表单，例如在前端，并帮助传输到数据库

托管bean可以链接到UI JSF组件，这样，例如，当您在网页上填写表单时，输入的值会自动分配到Java bean中的相应字段。托管JSFbean与JavaBeans类似，但单词Managed意味着它们可以直接链接到JSF组件。除了存储数据，它们还可能包含有关页面导航的信息

Answer 1

什么是JSF ManagedBean

Managed Bean is just an object defined by some class that has a name and scope.

通常，bean是视图的模型，用于保存视图中使用的组件的数据，并包含其属性

What role does it play in a three tier client-server framework?

发件人： http://craftedsw.blogspot.co.uk/2010/05/mvc-and-multi-tier-architecture.html

In component-centric frameworks like JSF, the pages (generally XHTML) have components that are bound to Java classes (known as backing beans in JSF). These components can be input texts, drop down lists, tables, etc, or even the entire page. Basically each component on the page can be bound to a Java class, that would behave like a Model and sometimes Controller for these components.

The backing beans are responsible to hold the state of the components and also handle events, validation, conversions, trigger business logic, update/refresh other components, fire events, listen to events, etc.