filter异常捕捉

    <%
        String action = request.getParameter("action");
        if ("accountException".equals(action)) {
        //    System.out.println("111");//true
            throw new AccountException("兄弟登陆了");
        }
    %>

    <a href="<%=request.getRequestURI() %>?action=accountException">click</a>

        try {
            chain.doFilter(request, response);
        } catch (Exception e) {
            String message = e.getMessage();
            request.setAttribute("message", message);
            request.getRequestDispatcher("/AccountException.jsp").forward(
                    request, response);
        }