统计当前在线人数:
1、web.listener下的CountLineListener:
public class CountLineListener implements HttpSessionListener {
public void sessionCreated(HttpSessionEvent se) {
ServletContext context=se.getSession().getServletContext();
Integer count=(Integer)context.getAttribute("count");
if(count==null){
count=1;
context.setAttribute("count",count);
}else{
count++;
context.setAttribute("count", count);
}
}
public void sessionDestroyed(HttpSessionEvent se) {
ServletContext context=se.getSession().getServletContext();
Integer count=(Integer)context.getAttribute("count");
count--;
context.setAttribute("count", count);
}
}
2、index.jsp
<body>
当前网站人数:${applicationScope.count} <br>
<%
application.setAttribute("name","zhangsan");
application.setAttribute("name","lisi");
application.removeAttribute("name");
session.setAttribute("city","baoding");
session.setAttribute("city","beijin");
session.removeAttribute("city");
request.setAttribute("name1","aaa");
request.setAttribute("name1","bbb");
request.removeAttribute("name1");
%>
</body>