Module mod_expires and ExpiresFilter (a Servlet API port of mod_expires) add Expires HTTP header and the max-age directive of the Cache-Control HTTP 

header in server responses and can set to be relative to either the time the source file was last modified, or to the time of the client access. 


<h3>
Tomcat 7 Servlet Filter
</h3>


Use the Filter if your JSF pages are served directly by Tomcat through the port it is listening to (http://domain.com:8080 for example). It can be 

configured per application through the web.xml of the application or container wide through the container web.xml. The following web.xml entry adds "Expires" and "Cache-Control: max-age=" headers to images, css and javascript.



<pre class="brush: xml">
&lt;filter>
 &lt;filter-name>ExpiresFilter&lt;/filter-name>
 &lt;filter-class>org.apache.catalina.filters.ExpiresFilter&lt;/filter-class>
 &lt;init-param>
 &lt;param-name>ExpiresByType image&lt;/param-name>
 &lt;param-value>access plus 1 month&lt;/param-value>
 &lt;/init-param> 
 &lt;init-param>
 &lt;param-name>ExpiresByType text/css&lt;/param-name>
 &lt;param-value>modification plus 3 weeks&lt;/param-value>
 &lt;/init-param>
 &lt;init-param>
 &lt;param-name>ExpiresByType application/javascript&lt;/param-name>
 &lt;param-value>access plus 1 month 15 days 2 hours&lt;/param-value>
 &lt;/init-param>
&lt;/filter> 

&lt;filter-mapping>
 &lt;filter-name>ExpiresFilter&lt;/filter-name>
 &lt;url-pattern>/*&lt;/url-pattern>
 &lt;dispatcher>REQUEST&lt;/dispatcher>
&lt;/filter-mapping>
</pre>



You can also use the alternate syntax ExpiresDefault. The following directive can be used to make documents expire 1 month after being 

accessed, by default. Replace all init-param directive from the previous example with below.



<pre class="brush: xml">
&lt;init-param>
 &lt;param-name>ExpiresDefault&lt;/param-name>
 &lt;param-value>access plus 1 month&lt;/param-value>
&lt;/init-param>
</pre>
 


Please refer to this Tomcat 7 documentation <a href="http://tomcat.apache.org/tomcat-7.0-doc/api/org/apache/catalina/filters/ExpiresFilter.html" 

class="news_link" target="_blank" title="ExpiresFilter documentation">http://tomcat.apache.org/tomcat-7.0-

doc/api/org/apache/catalina/filters/ExpiresFilter.html</a> for more Filter options.


Note that ExpiresFilter may override your com.sun.faces.defaultResourceMaxAge settings depending on the url-pattern of the Filter.


<h3>
Apache 2 mod_expires module
</h3>


The Servlet Filter does not work if your JSF pages and servlets are served by Apache. This is the case if you are using mod_jk connector. In this 

case use mod_expires. 


In Debian systems enable mod_expires like below



<pre class="brush: bash">
a2enmod expires
</pre>



Configuration format of the module is the same as the Servlet Filter. It can be configured in the virtual host, universally in the server 

configuration, or in your .htaccess.



<pre class="brush: xml">
&lt;IfModule mod_expires.c>
 ExpiresActive on
 ExpiresByType image/gif "access plus 1 month"
 ExpiresByType css/text "modification plus 1 month 15 days 2 hours"
&lt;/IfModule>
</pre>



or, the alternate syntax,


<pre class="brush: xml">
&lt;IfModule mod_expires.c>
 ExpiresActive on
 ExpiresDefault "access plus 1 month"
&lt;/IfModule>
</pre>


Restart Apache 2.



Please check the Apache 2 mod_expires documentation here <a href="http://httpd.apache.org/docs/current/mod/mod_expires.html
" target="_blank" class="news_link" title="Apache 2 expires module">http://httpd.apache.org/docs/current/mod/mod_expires.html</a> for more options.



In the above samples, both in the ExpiryFilter and in mod_expires, references to access may be replaced with modification and vice versa 

depending on your requirements. See the documentation for more information.



That's it. Good luck.

Improving page load with mod_expires and ExpiresFilter in JSF applications