Sometimes I see JSF URL is *.jsf, sometimes *.xhtml and sometimes /faces/*. Why?

问题

Been try to learn JSF, and sometimes I see the URL is *.jsf and sometimes is *.xhtml or /faces/*. Can someone fill my knowledge, please? When I create a JSF using Facelet, the file extension is .xhtml, so where does .jsf URL extension come from?

回答1:

The .jsf extension is where the FacesServlet is during the JSF 1.2 period often mapped on in the web.xml.

<servlet-mapping>
    <servlet-name>facesServlet</servlet-name>
    <url-pattern>*.jsf</url-pattern>
</servlet-mapping>

The .xhtml extension is of the actual Facelets file as you've physically placed in the webcontent of your webapp, e.g. Webapp/WebContent/page.xhtml.

If you invoke this page with the .jsf extension, e.g. http://localhost:8080/webapp/page.jsf then the FacesServlet will be invoked, locate the page.xhtml file and parse/render its JSF components. If the FacesServlet isn't invoked, then the enduser would end up getting the raw XHTML source code (which can be seen by rightclick, View Source).

Sometimes a *.faces extension or /faces/* foldermapping is been used. But this was from back in the JSF 1.0/1.1 ages. You're free to choose and use whatever mapping you'd like to let FacesServlet listen on, even if it's a nothing-saying *.xyz. The actual page itself should always have the .xhtml extension, but this is configureable by the following <context-param> in web.xml:

<context-param>
    <param-name>javax.faces.DEFAULT_SUFFIX</param-name>
    <param-value>.xml</param-value>
</context-param>

This will change the FacesServlet to locate page.xml instad of (default) page.xhtml.

More recently, with JSF/Facelets 2.0 a *.xhtml mapping is been used. In JSF/Facelets 1.x it was not possible to use the same mapping extension as the physical file. It would result in an infinite loop. But since JSF/Facelets 2.0 it is possible and this allows you to call the page by http://localhost:8080/webapp/page.xhtml.

<servlet-mapping>
    <servlet-name>facesServlet</servlet-name>
    <url-pattern>*.xhtml</url-pattern>
</servlet-mapping>

This way you don't need to configure some security restrictions to hide the raw source files away for cases whenever the enduser changes for example .jsf in URL to .xhtml in browser address bar. Only tooling (IDEs and plugins) and learning resources still need to catch up the advocated move from *.jsf to *.xhtml. As per JSF 2.3, the FacesServlet will by default be autoregistered on *.xhtml too (next to /faces/*, *.faces and *.jsf). This is backported to Mojarra 2.2.11.

See also:

• Can we use regular expressions in web.xml URL patterns?
• Set default home page via <welcome-file> in JSF project
• JSF returns blank/unparsed page with plain/raw XHTML/XML/EL source instead of rendered HTML output
• What is the difference between creating JSF pages with .jsp or .xhtml or .jsf extension
• Which XHTML files do I need to put in /WEB-INF and which not?
• Customize FacesServlet <url-pattern> to get rid of .xhtml extension

来源：https://stackoverflow.com/questions/3008395/sometimes-i-see-jsf-url-is-jsf-sometimes-xhtml-and-sometimes-faces-why