struts2登录设计思路的问题，求解！

Question

a页面是登录页面，登录成功就转到b页面，并且把a页面里的信息保存到session供操作表时使用，但是如果没有登录的话b页面是不允许访问的，输入b的地址要跳转到登录页面a，还有如果在firefox里成功进入了b,把b的地址复制到opera里怎样调到登录页面？地址复制应该是无效的，有好的解决方法吗？不要很模糊的回答用“拦截器”，”过滤器“，我想知道思路

Answer 1

web.xml文件中添加：

UserSessionFilter
com.yunfei.filter.UserSessionFilter

<filter-mapping>
    <filter-name>UserSessionFilter</filter-name>
    <url-pattern>这里写你要过滤页面的路径，如admin文件夹下的所有页面，则写/admin/*，如果是b页面，则写/b.jsp

                 </url-pattern>
</filter-mapping>

import java.io.IOException;
import java.util.List;

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.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.yunfei.pojo.User;
import com.yunfei.pojo.UserList;

public class UserSessionFilter implements Filter {

public void destroy() {
    // TODO Auto-generated method stub

}

public void doFilter(ServletRequest request, ServletResponse response,
        FilterChain chain) throws IOException, ServletException {
    HttpServletRequest req = (HttpServletRequest) request;
    HttpServletResponse res = (HttpServletResponse) response;
    String currentURL = req.getRequestURI(); // 取得根目录所对应的绝对路径:

    String targetURL = currentURL.substring(currentURL.indexOf("/", 1),
            currentURL.length()); // 截取到当前文件名用于比较

    //System.out.println(targetURL);
    HttpSession session = req.getSession();
    User u = (User) session.getAttribute("UserSession");
    //System.out.println("u1111111111111111111==" + session.getId());
    if (u != null) {

            chain.doFilter(request, response);

    } else {
        //System.out.println("----");
        req.getRequestDispatcher("/login.html").forward(req, res);
        return;
    }
}

public void init(FilterConfig filterConfig) throws ServletException {
    // TODO Auto-generated method stub

}

}