先进行授权，需要登陆，为什么登陆之后，这里为什么为空？

[SpriderMan]

public void onAuthenticationSuccess(HttpServletRequest request,
HttpServletResponse response, Authentication authentication)
throws ServletException, IOException {
SavedRequest savedRequest = requestCache.getRequest(request, response);

	if (savedRequest == null) {
		super.onAuthenticationSuccess(request, response, authentication);

		return;
	}

...}

为什么savedRequest会为空

[SpriderMan]

public SavedRequest getRequest(HttpServletRequest currentRequest,
HttpServletResponse response) {
HttpSession session = currentRequest.getSession(false);

	if (session != null) {
		return (SavedRequest) session.getAttribute(this.sessionAttrName);
	}

	return null;
}

发现是session为空导致的

[SpriderMan]

想不明白为什么session这里为什么会为null