RedirectAttributes 如何在过滤器中使用

Question

大侠们， 下午好，小弟有一Java 问题，想请教一下。
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain
     )
            throws IOException, ServletException {
    
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpSession session = request.getSession();
        HttpServletResponse reponse = (HttpServletResponse) servletResponse;        logger.info("*****Requested URL: " + request.getRequestURL() + "|" + df.format(session.getCreationTime()) + "|"
                + reponse.getStatus());        session.setAttribute("referer", request.getRequestURL().toString());
        // Do Authentication
        Object username = session.getAttribute("username");
        if (username == null) {
            logger.info("*****Unauthenticated.");
            redirectAttr.addFlashAttribute("alert", "You don't have the permission to access this page, Please Login!");
            reponse.sendRedirect("/portal/login");
            return;
        }
        // Do Authorization
        logger.info("*******" + username.toString() + "|" + request.getRequestURI());
        if (!auth.authorize(username.toString(), request.getRequestURI(), authorizesvc, applicationname)) {
            logger.info("*****Unauthorized for URL: " + request.getRequestURI());
            redirectAttr.addFlashAttribute("alert", "You don't have the permission to access this page, Please Login!");
            reponse.sendRedirect("/portal/login");
            return;
        }
}我想要使用 RedirectAttributes 过滤器，该如何使用啊， 在线等

Answer 1

public class SessionCheckFilter extends OncePerRequestFilter { @Override
protected void doFilterInternal(HttpServletRequest request,
HttpServletResponse response, FilterChain filterChain)
throws ServletException, IOException {
String uri = request.getRequestURI();
String ctxpath = request.getContextPath();
     HttpSession session = ((HttpServletRequest) request).getSession();
UserVO user = (UserVO) session.getAttribute(FrontContants.SESSION_USER);
if ((uri.indexOf("/jsp/login.jsp") > -1)
|| (uri.indexOf("/loginAction/login.do") > -1)
|| (uri.equals(ctxpath + "/"))) {
filterChain.doFilter(request, response);
} else {
if (user == null ) {
response.sendRedirect(ctxpath + "/jsp/login.jsp"); } else {
filterChain.doFilter(request, response);
}
}
}}

Answer 2

这个session 其实我也会； 就是不会用：RedirectAttributes redirectAttr 来实现显示错误信息；像这样：redirectAttr.addFlashAttribute("alert", "You don't have the permission to access this page）这样可以实现嘛？