登录时session.setAttribute("username",user_name);
判断是否登录:if(session.getAttribute("username")!=null&&!session.getAttribute("username").equals("")){登录;}else 没登录;
判断是否登录:if(session.getAttribute("username")!=null&&!session.getAttribute("username").equals("")){登录;}else 没登录;
<session-config>
<session-max>4096</session-max>
<session-timeout>30</session-timeout>
<enable-cookies>true</enable-cookies>
<enable-url-rewriting>true</enable-url-rewriting>
</session-config>
<session-timeout>30</session-timeout>指的是不活动状态下,session的有效时间