Maybe, Liferay could provide better solution for you to migrate from existing frameworks to portals and portlets.
I heard that the way Liferay supports migration of portlets is that we can migrate JSR-168-compliant portlets to Liferay, but we can migrate Liferay portlets to other JSR-168-compliant portals. I don't have any experience in migrating portlets across different platforms like this. But this is what I heard from the Liferay communities.
Co-author of SCMAD Exam Guide, Author of JMADPlus SCJP1.2, CCNA, SCWCD1.4, SCBCD1.3, SCMAD1.0, SCJA1.0, SCJP6.0
Venkata Sunil Yadiki
posted 10 years ago
Thanks for the info... Currently i am using JSF. But i just wanted to know if the solution for migrating would be a feasible option.I will take a look at the Liferay stuff...
If you're using JSF, you might find this JSF portlet tutorial helpful. It demonstrates how to take a Java Server Faces application and use the apache JSF bridge from the apache bridges project to allow the JSF app to be deployed as a portlet.
Java Server Faces Portlet Tutorial - Code and CBT for JSF Portlet Development