In JavaServer Faces (JSF) 2.0, Facelets is the default view declaration language (VDL) instead of JavaServer Pages (JSP). With Facelets, you don’t need to configure a view handler as you used to do in JSF 1.2. Facelets is a JSF-centric view technology.
Facelets is based on compositions. A composition defines a JSF UIComponents structure in a Facelets page. A Facelets application may consist of compositions defined in different Facelets pages and run as an application.
Facelets is a templating framework similar to Tiles. The advantage of Facelets over Tiles is that JSF UIComponents are pre-integrated with Facelets, and Facelets does not require a Facelets configuration file, unlike Tiles, which requires a Tiles configuration file.
JSF Validators and Converters may be added to Facelets. Facelets provides a complete expression language (EL) and JavaServer Pages Standard Tag Library (JSTL) support. Templating, re-use, and ease of development are some of the advantages of using Facelets in a Web application.
Facelets pages are XHTML pages by default. A Facelets application consists of the following configuration and templating files.
- A Facelet Template file, which is an XHTML page
- Facelet Header and Facelet Footer XHTML pages
- A JSF configuration file, faces-config.xml
- Facelet Composition page, which is also an XHTML page
