How can I set the welcome page to a struts action?

Personally, I'd keep the same setup you have now, but change the redirect for a forward. That avoids sending a header back to the client and having them make another request.

So, in particular, I'd replace the

<% 
  response.sendRedirect("/myproject/MyAction.action");
%>

in index.jsp with

<jsp:forward page="/MyAction.action" />

The other effect of this change is that the user won't see the URL in the address bar change from "http://server/myproject" to "http://server/myproject/index.jsp", as the forward happens internally on the server.

This is a pretty old thread but the topic discussed, i think, is still relevant. I use a struts tag - s:action to achieve this. I created an index.jsp in which i wrote this...

<s:action name="loadHomePage" namespace="/load" executeResult="true" />

As of the 2.4 version of the Servlet specification you are allowed to have a servlet in the welcome file list. Note that this may not be a URL (such as /myproject/MyAction.action). It must be a named servlet and you cannot pass a query string to the servlet. Your controller servlet would need to have a default action.

<servlet>
  <servlet-name>MyController</servlet-name>
  <servlet-class>com.example.MyControllerServlet</servlet-class>
</servlet>
<servlet-mapping>
  <servlet-name>MyController</servlet-name>
  <url-pattern>*.action</url-pattern>
</servlet-mapping>
<welcome-file-list>
  <welcome-file>MyController</welcome-file>
</welcome-file-list>

"Surely there's a better way!"

There isn't. Servlet specifications (Java Servlet Specification 2.4, "SRV.9.10 Welcome Files" for instance) state:

The purpose of this mechanism is to allow the deployer to specify an ordered list of partial URIs for the container to use for appending to URIs when there is a request for a URI that corresponds to a directory entry in the WAR not mapped to a Web component.

You can't map Struts on '/', because Struts kind of require to work with a file extension. So you're left to use an implicitely mapped component, such as a JSP or a static file. All the other solutions are just hacks. So keep your solution, it's perfectly readable and maintainable, don't bother looking further.

It appears that a popular solution will not work in all containers... http://www.theserverside.com/discussions/thread.tss?thread_id=30190

I would create a filter and bounce all requests to root back with forward responce. Hacks with creating home.do page looks ugly to me (One more thing to remember for you and investigate for someone who will support your code).