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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