Establish SSO and session sharing between two webapplications running on Tomcat 6

I have two web applications, webapp1 (JSF-Spring) and webapp2 (Struts) running on a single Tomcat 6.0. Webapp1 uses JSF phase listener to protect all the resources within the webapp. After user is authenticate开发者_StackOverflow社区d to webapp1, it renders a page from which webapp2 is invoked via an <iframe> tag.

My questions are:

1. How can SSO be established between webapp1 and webapp2?
2. How can session be shared between webapp1 and webapp2?

1. Replace the PhaseListener by a Filter which does basically the same job and use it on both webapps. This assumes that session is shared and that you've put the logged-in user in the session.

2. Set emptySessionPath attribute of the <Context> element of both webapps to true.

   <Context emptySessionPath="true">
   

   This can be provided by a /META-INF/context.xml file. See also the linked documentation.