Matt Raible has a post here discussing how to use Sitemesh to decorate multiple webapps. When applying this to various Struts 2 webapps that use Freemarker, I found the process required a little further fine tuning. I’ve outlined the steps I’ve taken to get this working here.

One key issue to keep in mind is that the struts 2 sitemesh filter that comes with Struts 2 cannot refer to decorators in other webapps. This isn’t documented anywhere and certainly tripped me up.

1. Configure a web app to host the decorators. This should have a web.xml that includes something like the following:
   <filter>
       <filter-name>sitemesh</filter-name>
       <filter-class>com.opensymphony.module.sitemesh.filter.PageFilter</filter-class>
   </filter>

   <filter-mapping>
       <filter-name>sitemesh</filter-name>
       <url-pattern>/*</url-pattern>
       <dispatcher>REQUEST</dispatcher>
       <dispatcher>FORWARD</dispatcher>
   </filter-mapping>
          
   <servlet>
       <servlet-name>sitemesh-freemarker</servlet-name>
       <servlet-class>com.opensymphony.module.sitemesh.freemarker.FreemarkerDecoratorServlet</servlet-class>
           <init-param>
                   <param-name>TemplatePath</param-name>
                   <param-value>/</param-value>
           </init-param>
           <init-param>
                   <param-name>default_encoding</param-name>
                   <param-value>ISO-8859-1</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>

   …

   Note that this webapp is thus set up basically just to use Freemarker and Sitemesh together as outlined here.

2. Struts 2 web apps that will use the shared decorators in some other webapp must NOT use the struts2-sitemesh PageFilter that comes with Struts 2, but instead use the PageFilter that comes with the regular sitemesh distribution:
<filter>
    <filter-name>sitemesh</filter-name>
    <filter-class>com.opensymphony.module.sitemesh.filter.PageFilter</filter-class>
</filter>
<filter-name>sitemesh</filter-name>
    <url-pattern>/*</url-pattern>
    <dispatcher>REQUEST</dispatcher>
    <dispatcher>FORWARD</dispatcher>
</filter-mapping>
3. Struts 2 web apps point to decorators in the host webapp, as outlined in MR’s post:
   <decorators>
       <excludes>
           <pattern>/styles/*</pattern>
           <pattern>/scripts/*</pattern>
           <pattern>/images/*</pattern>
           <pattern>/index.html</pattern>
           <pattern>/admBase/*</pattern>
           <pattern>/jforum.page?module=admBase*</pattern>
       </excludes>
    
       <!– load decorator from a different web-app deployed in the server –>
       <decorator name=“layout” webapp=“yourWebApp” page=“/WEB-INF/decorators/YourDecorator.ftl”>
           <pattern>/*</pattern>
       </decorator>

   </decorators>

4. crossContext must be set to true for all your webapps. (Your context elements will no doubt look considerably different, especially if you’re loading webapps from server.xml rather than individual context files)
<Context reloadable=“false” crossContext=“true”>
        <Loader delegate=“true”/>
</Context>

And you should be good to go.

I’ve been using Spring with Struts 2 for some time now– I love how it saves me from worrying about object creation and makes my code so much more testable. One recent problem I’ve encountered, though, has led to a bit of a “gotcha” that I hadn’t foreseen.

In general, I’m autowiring my Struts 2 actions by type so that I don’t have to configure beans for actions within my Spring applicationContext.xml. I tried doing this for an action that had two dependencies that I wanted to pass in through the constructor:

Upon executing the action I encountered the following cryptic exception (note spelling mistake):

Not terribly informative. Unfortunately Google searches yielded nothing despite that unique, improperly spelled exception message. I soon learned that any action where I wanted to pass in an IFacebookFacade suffered the same fate. After much investigation I discovered the source of my error: I had another bean defined for a class that was a subclass of an IFacebookFacade implementation in my applicationContext.xml. Thus, Spring found two objects that corresponded to the same interface and wasn’t sure how to autowire by type. It would be helpful if the error message was a little more informative..

Anyhow, the solution I used was to pass the fbFacade into UsersAction by setter injection:

This way, Spring will autowire by name and look for a bean with the same name as the property addressed by the setter. Job done.

Note that you could also resolve this issue by explicity defining a bean for the action in applicationContext.xml, but it is recommended to use declarative ways of specifying dependencies so as to minimise the amount of config in your applicationContext.xml. See this link for more info.

For a number of reasons, some time ago I decided to move away from using a programmatic authorization solution in a Struts 2 web app towards using Tomcat Container Managed Security (CMA). I now regret that decision as it’s caused me all sorts of issues. The three things that bother most, though, are the following:

1. When logging in directly from the login page without first requesting a protected resource, Tomcat throws up an error. Tomcat CMA mandates that you navigate directly to a protected resource before logging in, in which case it will display the login page instead. This seems awkward and is not the case with other servlet containers like JBoss.
2. I can’t specify a Struts 2 action as the login page. This means I have to have a separate JSP that contains all the relevant login markup, which is inconsistent with the use of the framework everywhere else in the application.
3. As far as I can tell, CMA does not play nice with my configuration of Sitemesh, Freemarker and Struts 2 across multiple webapps. I wasn’t able to get to the root cause of the problem. I have multiple webapps, some Struts 2, some not, that all use Freemarker and use the same Sitemesh decorators. The CMA login page would not display correctly for some of these.

Ultimately item 3 was the straw that broke the camel’s back. I’ve since moved to Spring Security, which I’ve found easy to configure and resolved all of the issues listed above.