我在用户登陆页面将每个用户的ID使用session保存下来,例如: session.setAttribute("UserID","ytang");我如何将所有用户登陆的这些session值一一取出来
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还是把登陆的人员信息保存到数据库中???
import javax.servlet.ServletContextAttributeEvent;
import javax.servlet.ServletContextAttributeListener;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletRequestAttributeEvent;
import javax.servlet.ServletRequestAttributeListener;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.http.HttpSessionActivationListener;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionBindingListener;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;public class S implements ServletContextAttributeListener, ServletContextListener, HttpSessionActivationListener, HttpSessionAttributeListener, HttpSessionBindingListener, HttpSessionListener, ServletRequestListener, ServletRequestAttributeListener {
/* (non-Java-doc)
* @see java.lang.Object#Object()
*/
public S() {
super();
} /* (non-Java-doc)
* @see javax.servlet.ServletContextAttributeListener#attributeAdded(ServletContextAttributeEvent arg0)
*/
public void attributeAdded(ServletContextAttributeEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.ServletContextAttributeListener#attributeRemoved(ServletContextAttributeEvent arg0)
*/
public void attributeRemoved(ServletContextAttributeEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.ServletContextAttributeListener#attributeReplaced(ServletContextAttributeEvent arg0)
*/
public void attributeReplaced(ServletContextAttributeEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.ServletContextListener#contextInitialized(ServletContextEvent arg0)
*/
public void contextInitialized(ServletContextEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.ServletContextListener#contextDestroyed(ServletContextEvent arg0)
*/
public void contextDestroyed(ServletContextEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.http.HttpSessionActivationListener#sessionWillPassivate(HttpSessionEvent arg0)
*/
public void sessionWillPassivate(HttpSessionEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.http.HttpSessionActivationListener#sessionDidActivate(HttpSessionEvent arg0)
*/
public void sessionDidActivate(HttpSessionEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.http.HttpSessionAttributeListener#attributeAdded(HttpSessionBindingEvent arg0)
*/
public void attributeAdded(HttpSessionBindingEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.http.HttpSessionAttributeListener#attributeRemoved(HttpSessionBindingEvent arg0)
*/
public void attributeRemoved(HttpSessionBindingEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.http.HttpSessionAttributeListener#attributeReplaced(HttpSessionBindingEvent arg0)
*/
public void attributeReplaced(HttpSessionBindingEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.http.HttpSessionBindingListener#valueBound(HttpSessionBindingEvent arg0)
*/
public void valueBound(HttpSessionBindingEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.http.HttpSessionBindingListener#valueUnbound(HttpSessionBindingEvent arg0)
*/
public void valueUnbound(HttpSessionBindingEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.http.HttpSessionListener#sessionCreated(HttpSessionEvent arg0)
*/
public void sessionCreated(HttpSessionEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.http.HttpSessionListener#sessionDestroyed(HttpSessionEvent arg0)
*/
public void sessionDestroyed(HttpSessionEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.ServletRequestListener#requestDestroyed(ServletRequestEvent arg0)
*/
public void requestDestroyed(ServletRequestEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.ServletRequestListener#requestInitialized(ServletRequestEvent arg0)
*/
public void requestInitialized(ServletRequestEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.ServletRequestAttributeListener#attributeAdded(ServletRequestAttributeEvent arg0)
*/
public void attributeAdded(ServletRequestAttributeEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.ServletRequestAttributeListener#attributeRemoved(ServletRequestAttributeEvent arg0)
*/
public void attributeRemoved(ServletRequestAttributeEvent arg0) {
// TODO Auto-generated method stub
} /* (non-Java-doc)
* @see javax.servlet.ServletRequestAttributeListener#attributeReplaced(ServletRequestAttributeEvent arg0)
*/
public void attributeReplaced(ServletRequestAttributeEvent arg0) {
// TODO Auto-generated method stub
}}
request.getSession().getAttribute("id")
* Created on 2005-3-4
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package listerner;
import javax.servlet.http.*;
import java.util.*;
/**
* @author panguozhang
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class SessionListener implements HttpSessionListener{
//映射表,存储sessionID与用户名之间的映射关系
public static HashMap hUserName=new HashMap();
//HttpSessionListener接口的方法
public void sessionCreated(HttpSessionEvent se){
}
public void sessionDestroyed(HttpSessionEvent se){
hUserName.remove(se.getSession().getId());
}
//判断用户是否已经登陆
public static boolean isAlreadyEntered(HttpSession session,String sUserName){
boolean flag=false;
if(hUserName.containsValue(sUserName)){
flag=true;
Iterator iter=hUserName.entrySet().iterator();
while(iter.hasNext()){
Map.Entry entry=(Map.Entry)iter.next();
Object key=entry.getKey();
Object value=entry.getValue();
if(((String)value).equals(sUserName)){
hUserName.remove(key);
}
}
hUserName.put(session.getId(),sUserName);
System.out.println("sUserName:"+sUserName);
}
else{
flag=false;
hUserName.put(session.getId(),sUserName);
System.out.println("sUserName:"+sUserName);
}
return flag;
}
//判断用户是否在线
public static boolean isOnline(HttpSession session){
boolean flag=true;
if(hUserName.containsKey(session.getId())){
flag=true;
}
else{
flag=false;
}
return flag;
}
}