String casLoginString = casLoginUrl + "?service=" + serviceString + "&" + "logoutCallbackUrl=" + logoutCallbackUrlString;
String casLoginString = casLoginUrl + "?service=" + serviceString;
    private void redirectToCAS(HttpServletRequest request, HttpServletResponse response)            throws IOException, ServletException {        String serviceString = URLEncoder.encode(CASServiceUrlProvider.getServiceUrl(request                .getRequestURL().toString()), URL_ENCODING);        String logoutCallbackUrlString = URLEncoder.encode(CASLogoutCallbackUrlProvider                .getLogoutCallbackUrl(request.getRequestURL().toString()), URL_ENCODING);        String casLoginString = casLoginUrl + "?service=" + serviceString + "&" + "logoutCallbackUrl="                + logoutCallbackUrlString;        ((HttpServletResponse) response).sendRedirect(casLoginString);    }