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What this article shares with you is about how to conduct an introductory analysis of JSF. The editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

I. introduction to JSF

JSF, namely JavaServer Faces, is a new technology used to construct the user interface of j2ee applications, which is suitable for applications based on MVC architecture.

The main functions of getting started with JSF are:

◆ Managed Bean tool

◆ verification tool

◆ 's rich and extensible component library

◆ plug-in rendering Toolkit

Navigation of ◆ in response to specific user events

◆ preserves application state across requests

◆ transformation model

This article will describe the above functions through the cnjsf application. To understand this article, you need to have some understanding of Web development, servlet, JSP, JavaBeans, and tag libraries.

II. How JSF starts working

A JSF application is essentially a Servlet or Java Server Pages (JSP) application that runs in a container compatible with Java (TM) 2 Platform, Enterprise Edition (J2EE (TM) platform). However, JSF does not require the use of JSP pages in your application, and you are free to choose to use Servlets or other templating technologies directly. If you do use JSF with the JSP container, you will benefit from the built-in JSF kernel and HTML component library through JSF's customer component tags. The JSF component represents Web controls such as text fields, forms, buttons, tables, check boxes, and so on.

When you create a JSP page using JSF, a component tree is created in the server's memory, with each component tag corresponding to an UIComponent instance in the tree. The framework uses the component tree to process application requests and create a rendered response. When a user generates an event, for example, by clicking a button, the JSF lifecycle processes the event and produces the appropriate response. This is a common example of most GUI-programmed forms. An event occurs whenever the user does anything, such as clicking a button or submitting a form. The event message is then sent to the server via HTTP. On the server side, it is a WEB container configured with a special servlet called Faces servlet. Faces servlet (javax.faces.webapp.FacesServlet) is the engine for all JSF applications. Each JSF application has a separate Faces servlet in the WEB container.

FacesServlet is the entry point into the JSF framework. It handles the request processing life cycle and acts as a front-end controller. JSF also has the concept of holding the context of important request information. The context object is called FacesContext (javax.faces.context.FacesContext). The context object is modified at every stage of the JSF lifecycle and is valid for each request.

The background processing of Faces servlet is quite complex. However, you don't need to know these details, just remember: Faces servlet creates a component tree for JSP pages, and control of the component tree corresponds to events. Faces servlet knows how to create a component tree because it has visited all the JSP pages in the current application. Faces servlet also creates an Event object and passes it to all registered listeners. You can get the component tree of this page through the FacesContext corresponding to the current request.

The above is how to conduct an introductory analysis of JSF. The editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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