拦截JSP页面，校验是否已登录详解及实现代码

拦截JSP页面，校验是否已登录

最近使用struts2做项目，需要拦截JSP以校验是否已经登，但struts2的过滤器链只能过滤action。后来发现在web.xml里可以直接增加javax.servlet.Filter实现类的过滤器，可以过滤JSP。请看代码

Filter实现类

<span style="font-size:18px;">package com.common;  import java.io.IOException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;  public class LoginFilter extends HttpServlet implements Filter {        private static final long serialVersionUID = 1L;      @Override    public void doFilter(ServletRequest request, ServletResponse response,        FilterChain chain) throws IOException, ServletException {      HttpServletRequest req = (HttpServletRequest)request;      HttpServletResponse res = (HttpServletResponse)response;      String path = req.getContextPath();     String indexPath = req.getScheme()+"://"+req.getServerName()+":"+req.getServerPort()+path+ "/pages/login.jsp";     if(req.getRequestURI().endsWith("login.jsp"))     {       chain.doFilter(request, response);        return;     }          Object loginuser = req.getSession().getAttribute("<strong><span style="color:#ff0000;">loginSession</span></strong>");      if(loginuser == null){       res.sendRedirect(indexPath);        return;      }     chain.doFilter(request, response);    }      @Override    public void init(FilterConfig arg0) throws ServletException {      // TODO Auto-generated method stub     }    }  </span> 

登录方法：

<span style="font-size:18px;"> public String login()   {     Login login = new Login();            //.......校验登录信息     ActionContext ctx = ActionContext.getContext();     Map<String, Object> session = ctx.getSession();     session.put("<strong><span style="color:#ff0000;">loginSession</span></strong>", login);     return "success";   }</span> 

web.xml配置

<filter>     <filter-name>setlog</filter-name>     <filter-class>com.common.LoginFilter</filter-class>  </filter>  <filter-mapping>     <filter-name>setlog</filter-name>     <url-pattern>/pages/home.jsp</url-pattern>    <url-pattern>/pages/channel/*</url-pattern>    <url-pattern>/pages/content/*</url-pattern>    <url-pattern>/pages/product/*</url-pattern>    <url-pattern>/pages/vodtask/*</url-pattern> </filter-mapping> 

注意，如果页面上使用了框架，则可能导致session超时后退出到登录页面，此时登录页面显示在框架的某个子页面，解决方法，在登录页面加入如下代码即可。

<span style="font-size: 18px;">  <script language="javascript">       if (top != window)         top.location.href = window.location.href;     </script></span> 

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