如何从过滤器确定哪个页面为 RequestDispatcher 的转发提供服务？

Question

我有一个过滤器，用于处理请求以记录它们，因此我可以跟踪哪个会话在什么时间使用什么请求参数访问页面。效果很好...从 jsp 发送到 jsp，或者直接调用 jsp。但是，当将表单发布到 servlet 并将该请求转发到新的 jsp 时，我无法看到该请求被转发到哪个 jsp。

例如，假设我有一个登录页面，它发布到 LoginServlet，然后将请求转发到 index.jsp 或 index1.jsp。如何从请求中确定 LoginServlet 返回的是 index.jsp 还是 index1.jsp？

这是在使用 2.3 servlet 规范的 java 1.5 环境中。

public class PageLogFilter implements Filter {

FilterConfig filterConfig = null;
public void init(FilterConfig filterConfig) throws ServletException {
    this.filterConfig = filterConfig;
}
public void destroy() {
    this.filterConfig = null;
}

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
    throws IOException, ServletException {
    try {
        if (request instanceof HttpServletRequest) {
            HttpServletRequest req = (HttpServletRequest) request;
            HttpSession session = req.getSession(false);

                //For non-forwards, I can call req.getRequestURI() to determine which 
                //page was returned. For forwards, it returns me the URI of the  
                //servlet which processed the post. I'd like to also get the URI
                //of the jsp to which the request was forwarded by the servlet
            }
        }
    } catch (Exception e) {
        System.out.println("-- ERROR IN PageLogFilter: " + e.getLocalizedMessage());
    }
    chain.doFilter(request, response);
}
}

Answer 1

在 chain.doFilter(..) 之后调用 request.getRequestURI()