web.xml

    <filter>
		<filter-name>sitemesh</filter-name>
		<filter-class>org.apache.struts2.sitemesh.FreeMarkerPageFilter</filter-class>
	</filter>


decorators.xml

<decorators defaultdir="/WEB-INF/decorators">
	<excludes>
        <!-- Exclude Struts2 Stuff -->
        <pattern>/dojo/*</pattern>
        <pattern>/struts/*</pattern>
        <pattern>/dwr/*</pattern>
        <pattern>/js/*</pattern>
        <pattern>/img/*</pattern>
        <pattern>/images/*</pattern>
        <pattern>/themes/*</pattern>
    </excludes>
    <!-- 
	<decorator name="default" page="main.jsp">
		<pattern>/*</pattern>
	</decorator>
	 -->
	<decorator name="default" page="main.ftl">
		<pattern>/*</pattern>
	</decorator>
	
</decorators>


sitemesh.xml

<sitemesh>
	<property name="decorators-file" value="/WEB-INF/decorators.xml" />
	<excludes file="${decorators-file}" />

	<page-parsers>
		<parser content-type="text/html"
			class="com.opensymphony.module.sitemesh.parser.HTMLPageParser" />
	</page-parsers>

	<decorator-mappers>
		<mapper
			class="com.opensymphony.module.sitemesh.mapper.ConfigDecoratorMapper">
			<param name="config" value="${decorators-file}" />
		</mapper>
	</decorator-mappers>
</sitemesh>


dans le main.ftl :

${title}

${body}