Read user-id / sap-name
i have an Java WebDynpro Application and want to read the user-id / sap-name of the user visiting the Java WD site. The Java WD application is public and on an application server where the visitor has no user in the system! I want to read the user-id, which the user has on the portal (another application server), or for example from the single sign on SSO.
Is there any possibility to read the user-id from SSO or via a cookie or something else? I just need the user-id or the sap-name. No password and no authorization needed!