struts2.2.1关于sitemesh和freemarker整合的细节-优快云博客

本文介绍如何在Struts2.2.1及更高版本中正确配置Sitemesh和Freemarker，确保装饰器功能正常工作。文章强调了从2.1.3版本开始的新过滤器和监听器配置，并提供了具体的XML示例。

有段时间没有使用struts2了，上了官网发现已经更新到2.2.1版本，没有细看note，照着以前老的方式配置web.xml，发现装饰器sitemesh对freemarker不起作用，折腾了一整天。最后还是老老实实看官方的文档，发现以前书上推荐的配置已经过时。老的一般配置如下：

<filter>
   <filter-name>ActionContextCleanUp</filter-name>
   <filter-class>org.apache.struts2.dispatcher.ActionContextCleanUp</filter-class>
</filter>
<filter>
   <filter-name>sitemesh</filter-name>
   <filter-class>com.opensymphony.module.sitemesh.filter.PageFilter</filter-class>
</filter>
<filter>
   <filter-name>struts2</filter-name>
   <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
</filter>

从struts2.1.3开始ActionContextCleanUp 和 FilterDispatcher过滤器，已经不建议使用了。将使用StrutsPrepareFilter 和StrutsExecuteFilter拦截器替代。正确的配置方式如下：

<filter>
		<filter-name>struts-prepare</filter-name>
		<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareFilter</filter-class>
	</filter>
	<filter>
        <filter-name>sitemesh</filter-name>
        <filter-class>com.opensymphony.sitemesh.webapp.SiteMeshFilter</filter-class>
    </filter>
	<filter>
    	<filter-name>struts-execute</filter-name>
    	<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsExecuteFilter</filter-class>
	</filter>
	
	<filter-mapping>
		<filter-name>struts-prepare</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	<filter-mapping>
        <filter-name>sitemesh</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
        <dispatcher>INCLUDE</dispatcher>
    </filter-mapping>
	<filter-mapping>
		<filter-name>struts-execute</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	
	<servlet>
        <servlet-name>sitemesh-freemarker</servlet-name>
        <servlet-class>org.apache.struts2.sitemesh.FreemarkerDecoratorServlet</servlet-class>
        <init-param>
            <param-name>default_encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>sitemesh-freemarker</servlet-name>
        <url-pattern>*.ftl</url-pattern>
    </servlet-mapping>
	<listener>
        <listener-class>org.apache.struts2.dispatcher.ng.listener.StrutsListener</listener-class>
    </listener>

注意：

1. com.opensymphony.sitemesh.webapp.SiteMeshFilter这个过滤器是必需的，否则装饰不起作用

2. 为了支持FreeMaker或Velocity，必须添加org.apache.struts2.sitemesh.FreemarkerDecoratorServlet这个Servlet，官方原话：

写道

From 2.2+ the recommended way to use Freemarker with Sitemesh is through the org.apache.struts2.sitemesh.FreemarkerDecoratorServlet servlet

3. 而已从2.2.x开始，必须添加org.apache.struts2.dispatcher.ng.listener.StrutsListener这个监听器

写道

From 2.2+ the new com.opensymphony.sitemesh.webapp.SiteMeshFilter filter and Struts org.apache.struts2.dispatcher.ng.listener.StrutsListener context listener must be added to web.xml,

4. 这样sitemesh装饰器才能在freemarker模板中起作用。