Jsp/servlet 标准不要求一个web容器支持分布式应用,但是他一定要支持HttpSessionActivationListener借口,以使代码可以支持分布式环境。一般免费的web容器都不支持分布式,weblogic websphere是支持的。为了负载均衡或者fail-over,web容器可以迁移一个session到其他的jvm.session的passivation是指非活动的session被写入持久设备(比如硬盘)。activate自然就是相反的过程。在分布式环境中切换的属性必须实现serializable接口。
一般情况下他和HttpSessionBindingListener一起使用。
比如一个属性类,
public class attributeClass implements HttpSessionBindingListener,HttpSessionActivationListener{
//HttpSessionActivationListener
public void sessionDidActivate(HttpSessionEvent se)
{ logout("sessionDidActivate("+se.getSession().getId()+")");//激活
}
public void sessionWillPassivate(HttpSessionEvent se)
{//被传送到别的jvm或 写到硬盘
logout("sessionWillPassivate("+se.getSession().getId()+")");
}
//HttpSessionBindingListener
public void valueBound(HttpSessionBindingEvent event)
{ //被设置到session中(setAttribute)
logout("valueBound("+event.getSession().getId()+event.getValue()+")");
}
public void valueUnbound(HttpSessionBindingEvent event)
{ //从session中解除(removeAttribute)
logout("valueUnbound("+event.getSession().getId()+event.getValue()+")");
}
}
这样你就可以将它加到session中
public class AAAServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession();
session.setAttribute("attribute",attributeClass);
}
}
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