Add SSO mode with CAS problem,help!

[Migrated From Jforum.net]

hi Rafael , Monroe
I added Jforum SSO mode with the Yale CAS(http://www.ja-sig.org/products/cas/index.html), CasUserSSO.java

package net.jforum.sso;

import net.jforum.context.RequestContext;
import net.jforum.entities.UserSession;
import net.jforum.util.preferences.ConfigKeys;
import net.jforum.util.preferences.SystemGlobals;
import org.apache.log4j.Logger;

import edu.yale.its.tp.cas.client.*;

public class CasUserSSO implements SSO {

	static final Logger logger = Logger.getLogger(CasUserSSO.class.getName());

	public String authenticateUser(RequestContext request) {
		String username = null;

		String errorCode = null;

		String errorMessage = null;

		String xmlResponse = null;

		String ticket = request.getParameter("ticket");
		/* instantiate a new ServiceTicketValidator */
		ServiceTicketValidator sv = new ServiceTicketValidator();
		if (ticket != null) {
			try {
				/* set its parameters */
				sv.setCasValidateUrl("https://app1.okwan.com:8443/cas/login");
				sv
						.setProxyCallbackUrl("https://app1.okwan.com:8443/cas/serviceValidate");
				sv.setService("http://bbs.mydomain.com:8080");
				sv.setServiceTicket(ticket);
				/* contact CAS and validate */
				sv.validate();
				/*
				 * if we want to look at the raw response, we can use
				 * getResponse()
				 */
				xmlResponse = sv.getResponse();

				if (sv.isAuthenticationSuccesful()) {
					username = sv.getUser();
				} else {
					errorCode = sv.getErrorCode();
					errorMessage = sv.getErrorMessage();
				}
			} catch (Exception exc) {
				System.out.println(exc.getMessage());
			}
		}
		return username;
	}

	public boolean isSessionValid(UserSession userSession,
			RequestContext request) {
		ServiceTicketValidator sv = new ServiceTicketValidator();
		String remoteUser =sv.getUser();
        //user has since logged out
		if (remoteUser == null && userSession.getUserId() != SystemGlobals.getIntValue(ConfigKeys.ANONYMOUS_USER_ID)) {
			return false;
		}
		// user has since logged in
		else if (remoteUser != null
				&& userSession.getUserId() == SystemGlobals.getIntValue(ConfigKeys.ANONYMOUS_USER_ID)) {
			return false;
		}
		// user has changed user
		else if (remoteUser != null && !remoteUser.equals(userSession.getUsername())) {
			return false;
		}    
		return true;

	}
}

modify SystemGlobals.properties settings

authentication.type = sso
sso.implementation = org.herowu.sso.CasUserSSO
sso.redirect = https://app1.okwan.com:8443/cas/

copy casclient.jar to lib/, restart Tomcat
The site run is OK,but can't SSO Login! Look at the tomcat logs.It's not error info.
Test account ID:test password:123456
I don't acquaint with the CAS, hope to help me the SSO code which adjusts to try a top.
Thank you very much!
[originally posted on jforum.net by herowu]