acegi security实践教程—form认证之debug调试

     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException,
                ServletException {
            if (!(request instanceof HttpServletRequest)) {
                 throw new ServletException( "Can only process HttpServletRequest");
           }

            if (!(response instanceof HttpServletResponse)) {
                 throw new ServletException( "Can only process HttpServletResponse");
           }

           HttpServletRequest httpRequest = (HttpServletRequest) request;
           HttpServletResponse httpResponse = (HttpServletResponse) response;

            if (requiresAuthentication(httpRequest, httpResponse)) {
                 if ( logger.isDebugEnabled()) {
                      logger.debug( "Request is to process authentication");
                }

                Authentication authResult;

                 try {
                     onPreAuthentication(httpRequest, httpResponse);
                     authResult = attemptAuthentication(httpRequest);
                }
                 catch (AuthenticationException failed) {
                      // Authentication failed
                     unsuccessfulAuthentication(httpRequest, httpResponse, failed);

                      return;
                }

                 // Authentication success
                 if ( continueChainBeforeSuccessfulAuthentication) {
                     chain.doFilter(request, response);
                }

                successfulAuthentication(httpRequest, httpResponse, authResult);

                 return;
           }

           chain.doFilter(request, response);
     }

 if (!SecurityContextHolder.getContext().getAuthentication().isAuthenticated() || alwaysReauthenticate) {
                 try {
                     authenticated = this. authenticationManager.authenticate(SecurityContextHolder. getContext()
                                .getAuthentication());
                }
                 catch (AuthenticationException authenticationException) {
                      throw authenticationException;
                }

                 // We don‘t authenticated.setAuthentication(true), because each
                 // provider should do that
                 if ( logger.isDebugEnabled()) {
                      logger.debug( "Successfully Authenticated: " + authenticated.toString());
                }

                SecurityContextHolder. getContext().setAuthentication(authenticated);
           }
            else {
                authenticated = SecurityContextHolder.getContext().getAuthentication();

                 if ( logger.isDebugEnabled()) {
                      logger.debug( "Previously Authenticated: " + authenticated.toString());
                }
           }