Session超时跳转到指定页面（filter实现）解决了图片被过滤问题

来源：互联网发布：infinite综艺知乎编辑：程序博客网时间：2024/05/13 07:04

package com.myplan.checkloginfilter;import javax.servlet.*;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import java.io.IOException;import java.io.PrintWriter;/**    * 用于检测用户是否登陆的过滤器，如果未登录或超时，则重定向到指的登录页面<p>      */public class CheckLoginFilter extends HttpServlet implements Filter {    public void doFilter(ServletRequest request, ServletResponse response,            FilterChain filterChain) {        try {            HttpServletRequest hsr = (HttpServletRequest) request;            HttpSession session = hsr.getSession();            if (hsr.getRequestURI().startsWith(                    hsr.getContextPath() + "/login.jsp")                    || hsr.getRequestURI().startsWith(                            hsr.getContextPath() + "/login.do")                    || hsr.getRequestURI().equals(hsr.getContextPath() + "/")                    ) {                // 请求登陆页面，所以放过                  System.out.println("放过login");                filterChain.doFilter(request, response);            } else {                if (session.getAttribute("employeeEmail") != null) {                    //这里session存在，那么则登陆，放过session                      // 已登录，放过请求                      System.out.println("test filter chain");                    filterChain.doFilter(request, response);                } else {                    //session超期后，自然session就是空了，那么则跳转到指定的页面就可以了                      // 未登录，跳转到登录页                                          PrintWriter out = response.getWriter();                    out.print("<script>window.top.location.href='http://blog.163.com/girl_lihuiyue@126/blog/"                            + hsr.getContextPath() + "';</script>");                }            }        } catch (ServletException sx) {        } catch (IOException iox) {        }    }    public void destroy() {    }    public void init(FilterConfig filterConfig) throws ServletException {    }}

使用filter导致跳转到登陆页面的图片不显示。添加红色字体部分，跳过图片的过滤。

web.xml相应的配置

<filter>       <filter-name>CheckLoginFilter</filter-name>       <filter-class>com.myplan.checkloginfilter.CheckLoginFilter</filter-class>  </filter>   <filter-mapping>      <filter-name>CheckLoginFilter</filter-name>      <url-pattern>*.jsp</url-pattern>   </filter-mapping> <span style="color:#FF0000;">如果使用session的话，配置 <session-config>       <!-- 以分钟为单位 -->       <session-timeout>30</session-timeout>   </session-config></span>

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