session过期，调到登录页面操作

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

import org.apache.shiro.SecurityUtils;
import org.apache.shiro.session.Session;
import org.apache.shiro.session.mgt.SessionKey;
import org.apache.shiro.subject.support.DefaultSubjectContext;
import org.apache.shiro.web.session.mgt.WebSessionKey;

public class SessionFilter extends BaseOperAction implements Filter {
private ScyMenu scyMenu = new ScyMenu();// 列表

public void destroy() {

}

public void doFilter(ServletRequest arg0, ServletResponse arg1,
FilterChain arg2) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) arg0;
HttpServletResponse response = (HttpServletResponse) arg1;
HttpSession session = request.getSession();
String id = session.getId();
boolean authenticated = isAuthenticated(id, request, response);
// if (!authenticated) {
// String errors = "您还没有登录，或者session已过期。请先登陆!";
// request.setAttribute("Message", errors);
// // 跳转至登录页面
// request.getRequestDispatcher("/Home_login.action?act=login").forward(arg0, arg1);
// } else {
// arg2.doFilter(request, response);
// }
}

public boolean isAuthenticated(String sessionID,
HttpServletRequest request, HttpServletResponse response) {
boolean status = false;
SessionKey key = new WebSessionKey(sessionID, request, response);
try {
Session se = SecurityUtils.getSecurityManager().getSession(key);
Object obj = se
.getAttribute(DefaultSubjectContext.AUTHENTICATED_SESSION_KEY);
if (obj != null) {
status = (Boolean) obj;
}
} catch (Exception e) {
e.printStackTrace();
} finally {
Session se = null;
Object obj = null;
}

return status;
}

public void init(FilterConfig arg0) throws ServletException {

}

public Entity getModel() {
return scyMenu;
}

}