SavedRequestAwareAuthenticationSuccessHandler源码分析

/**
 * An authentication success strategy which can make use of the
 * {@link org.springframework.security.web.savedrequest.DefaultSavedRequest} which may
 * have been stored in the session by the {@link ExceptionTranslationFilter}. When such a
 * request is intercepted and requires authentication, the request data is stored to
 * record the original destination before the authentication process commenced, and to
 * allow the request to be reconstructed when a redirect to the same URL occurs. This
 * class is responsible for performing the redirect to the original URL if appropriate.
 * <p>
 * Following a successful authentication, it decides on the redirect destination, based on
 * the following scenarios:
 * <ul>
 * <li>If the {@code alwaysUseDefaultTargetUrl} property is set to true, the
 * {@code defaultTargetUrl} will be used for the destination. Any
 * {@code DefaultSavedRequest} stored in the session will be removed.</li>
 * <li>If the {@code targetUrlParameter} has been set on the request, the value will be
 * used as the destination. Any {@code DefaultSavedRequest} will again be removed.</li>
 * <li>If a {@link org.springframework.security.web.savedrequest.SavedRequest} is found in
 * the {@code RequestCache} (as set by the {@link ExceptionTranslationFilter} to record
 * the original destination before the authentication process commenced), a redirect will
 * be performed to the Url of that original destination. The {@code SavedRequest} object
 * will remain cached and be picked up when the redirected request is received (See
 * <a href="
 * {@docRoot}/org/springframework/security/web/savedrequest/SavedRequestAwareWrapper.html">SavedRequestAwareWrapper</a>).
 * </li>
 * <li>If no {@link org.springframework.security.web.savedrequest.SavedRequest} is found,
 * it will delegate to the base class.</li>
 * </ul>
 *
 * @author Luke Taylor
 * @since 3.0
 */
public class SavedRequestAwareAuthenticationSuccessHandler extends SimpleUrlAuthenticationSuccessHandler {

    protected final Log logger = LogFactory.getLog(this.getClass());

    private RequestCache requestCache = new HttpSessionRequestCache();

    @Override
    public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response,
          Authentication authentication) throws ServletException, IOException {
       SavedRequest savedRequest = this.requestCache.getRequest(request, response);
       if (savedRequest == null) {
          super.onAuthenticationSuccess(request, response, authentication);
          return;
       }
       String targetUrlParameter = getTargetUrlParameter();
       if (isAlwaysUseDefaultTargetUrl()
             || (targetUrlParameter != null && StringUtils.hasText(request.getParameter(targetUrlParameter)))) {
          this.requestCache.removeRequest(request, response);
          super.onAuthenticationSuccess(request, response, authentication);
          return;
       }
       clearAuthenticationAttributes(request);
       // Use the DefaultSavedRequest URL
       String targetUrl = savedRequest.getRedirectUrl();
       getRedirectStrategy().sendRedirect(request, response, targetUrl);
    }

    public void setRequestCache(RequestCache requestCache) {
       this.requestCache = requestCache;
    }

}