HttpSessionBindingListener 實現在線用戶統計

** * OnLineUsers.java * 功能:用戶單點登錄 * 高春虎 * 2009-3-7 */ import javax.servlet.http.*; import javax.servlet.*; import java.util.*; public class OnLineUsers implements HttpSessionBindingListener { String yhm; public OnLineUsers(String yhm) { this.yhm = yhm; } public void valueBound(HttpSessionBindingEvent event) { HttpSession session = event.getSession(); ServletContext context = session.getServletContext(); HashMap<String, String> olu = (HashMap<String, String>) context .getAttribute("OnLineUsers"); if (olu == null) { olu = new HashMap<String, String>(); context.setAttribute("OnLineUsers", olu); } olu.put(yhm, session.getId()); } public void valueUnbound(HttpSessionBindingEvent event) { HttpSession session = event.getSession(); ServletContext context = session.getServletContext(); HashMap<String, String> olu = (HashMap<String, String>) context .getAttribute("OnLineUsers"); if (olu != null) { olu.remove(yhm); } } } 

 

 

在用戶登錄時只要執行"OnLineUsers olu = new OnLineUsers(request.getSession().getAttribute(
    "U_YHM").toString());"即可實現用戶的sessionid綁定