The process of deploying a Spring Portlet MVC application is no different than deploying any JSR-168 Portlet application. However, this area is confusing enough in general that it is worth talking about here briefly.

Generally, the portal/portlet container runs in one webapp in your servlet container and your portlets run in another webapp in your servlet container. In order for the portlet container webapp to make calls into your portlet webapp it must make cross-context calls to a well-known servlet that provides access to the portlet services defined in your portlet.xml file.

The JSR-168 specification does not specify exactly how this should happen, so each portlet container has its own mechanism for this, which usually involves some kind of “deployment process” that makes changes to the portlet webapp itself and then registers the portlets within the portlet container.

At a minimum, the web.xml file in your portlet webapp is modified to inject the well-known servlet that the portlet container will call. In some cases a single servlet will service all portlets in the webapp, in other cases there will be an instance of the servlet for each portlet.

Some portlet containers will also inject libraries and/or configuration files into the webapp as well. The portlet container must also make its implementation of the Portlet JSP Tag Library available to your webapp.

The bottom line is that it is important to understand the deployment needs of your target portal and make sure they are met (usually by following the automated deployment process it provides). Be sure to carefully review the documentation from your portal for this process.

Once you have deployed your portlet, review the resulting web.xml file for sanity. Some older portals have been known to corrupt the definition of the ViewRendererServlet, thus breaking the rendering of your portlets.