Custom Authentication Failure URL Handler, Accepting No Slash URLs.

NoSlashAuthenticationFailureHandler.java

public class NoSlashAuthenticationFailureHandler implements AuthenticationFailureHandler {
    
    protected final Log logger = LogFactory.getLog(getClass());
    private String defaultFailureUrl;

    public NoSlashAuthenticationFailureHandler() {
    }

    public NoSlashAuthenticationFailureHandler(String defaultFailureUrl) {
        setDefaultFailureUrl(defaultFailureUrl);
    }

    public void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response,
            AuthenticationException exception) throws IOException, ServletException {
        if (defaultFailureUrl == null) {
            logger.debug("No failure URL set, sending 401 Unauthorized error");
            response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Authentication Failed: " + exception.getMessage());
        } else {
            logger.debug("Redirecting to " + defaultFailureUrl);
            response.sendRedirect(defaultFailureUrl);
        }
    }

    /**
     * The URL which will be used as the failure destination.
     * @param defaultFailureUrl the failure URL, for example "loginFailed.jsp".
     */
    public void setDefaultFailureUrl(String defaultFailureUrl) {
        this.defaultFailureUrl = defaultFailureUrl;
    }
}