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