forward html header parameter to jsf back bean

I have two servers one is just for authentication and forward request with userId in header parameter other server runs application on JSF (1.2). how can I retrieve parameter from request and put in ba开发者_开发问答cking beans.

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I do something similar for a single sign on authentication module. A proxy server inserts a username into the HTTP request header. This can be retrieved from the FacesContext like so:

Map<String, String> requestHeaders = context.getExternalContext().getRequestHeaderMap();
String userName = requestHeaders.get(requestHeaderName);