我已经访问了JavaFilterImplementation进行会话检查链接，该链接介绍了有关Spring安全性的信息。我没有得到我需要的帮助。

应用过滤器后，login.jsp无法加载CSS和图像。

我正在尝试一个简单的示例，该示例在web.xml中提供过滤器，并将该过滤器应用于login.jsp以外的页面。Web.xml文件是：

<filter>
    <filter-name>struts2</filter-name>
    <filter-class>
         org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
    </filter-class>
</filter>
<filter-mapping>
    <filter-name>struts2</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>
 <filter>
 <filter-name>AuthenticationFilter2</filter-name>
 <filter-class>filter.AuthorizationFilter2</filter-class>
 <init-param>
    <param-name>avoid-urls</param-name>
    <param-value>login.jsp</param-value>
 </init-param>`
 <filter>

过滤器类是：

    private ArrayList<String> urlList;

public void destroy() {
    // TODO Auto-generated method stub
    System.out.println("authorization filter2 destroy method....");
}




public void doFilter(ServletRequest req, ServletResponse res,
        FilterChain chain) throws IOException, ServletException {

    System.out.println("authorization filter2 doFilter method....");

    HttpServletRequest request = (HttpServletRequest) req;
    HttpServletResponse response = (HttpServletResponse) res;
    String url = request.getServletPath();

    System.out.println("ppp:"+request.getRequestURL());

    System.out.println("url is :"+url);

    boolean allowedRequest = false;

    System.out.println("url list is :"+urlList);

    if(urlList.contains(url.substring(1))) {
        allowedRequest = true;
    }
    System.out.println("request allowed....."+allowedRequest);     
    if (!allowedRequest) {

        Map session = ActionContext.getContext().getSession();

        /*HttpSession session = request.getSession(false);*/
       /* if (null == session) {
            response.sendRedirect("login.jsp");
        }*/

        System.out.println("session contains login :"+session.containsKey("login"));



        if(!session.containsKey("login")){
            response.sendRedirect("login.jsp");
        }

    }

    chain.doFilter(req, res);
}

public void init(FilterConfig config) throws ServletException {
    System.out.println("authorization filter2 init method....");
    String urls = config.getInitParameter("avoid-urls");
    StringTokenizer token = new StringTokenizer(urls, ",");

    urlList = new ArrayList<String>();

    while (token.hasMoreTokens()) {
        urlList.add(token.nextToken());

    }
}

登录页面包含css并images根据要求。

请帮帮我。谢谢。