import java.util.ArrayList;
import javax.servlet.annotation.WebListener;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
import com.my.entity.User;
import com.my.util.SessionUtil;

/**
 * 计数监听器
 */
@WebListener
public class MyHttpSessionListener implements HttpSessionListener {
	
	private int userNumber = 0;
	
	@Override
	public void sessionCreated(HttpSessionEvent arg0) {
		userNumber++;
		arg0.getSession().getServletContext().setAttribute("userNumber", userNumber);
	}

	@Override
	public void sessionDestroyed(HttpSessionEvent arg0) {
		userNumber--;
		arg0.getSession().getServletContext().setAttribute("userNumber", userNumber);
		
		ArrayList<User> userList = null;//在线用户List
		
		userList = (ArrayList<User>)arg0.getSession().getServletContext().getAttribute("userList");
		
		if(SessionUtil.getUserBySessionId(userList, arg0.getSession().getId())!=null){
			userList.remove(SessionUtil.getUserBySessionId(userList, arg0.getSession().getId()));
		}
	}
}

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.annotation.WebListener;
import javax.servlet.http.HttpServletRequest;

import com.my.entity.User;
import com.my.util.SessionUtil;
@WebListener
public class MyServletRequestListener implements ServletRequestListener {

	private ArrayList<User> userList;//在线用户List
	
	@Override
	public void requestDestroyed(ServletRequestEvent arg0) {

	}

	@Override
	public void requestInitialized(ServletRequestEvent arg0) {
		
		userList  = (ArrayList<User>)arg0.getServletContext().getAttribute("userList");
		
		if(userList==null)
			userList = new ArrayList<User>();
		
		HttpServletRequest request = (HttpServletRequest) arg0.getServletRequest();
		String sessionIdString = request.getSession().getId();
		
		if(SessionUtil.getUserBySessionId(userList,sessionIdString)==null){
			User user = new User();
			user.setSessionIdString(sessionIdString);
			user.setFirstTimeString(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));
			user.setIpString(request.getRemoteAddr());
			userList.add(user);
		}
		arg0.getServletContext().setAttribute("userList", userList);
	}
}

import java.util.ArrayList;
import com.my.entity.User;

public class SessionUtil {

	public static Object getUserBySessionId(ArrayList<User> userList, String sessionIdString) {
		for (int i = 0; i < userList.size(); i++) {
			User user = userList.get(i);
			if (user.getSessionIdString().equals(sessionIdString)) {
				return user;
			}
		}
		return null;
	}
}

public class User {

	private String sessionIdString;

	private String ipString;

	private String firstTimeString;

	public String getSessionIdString() {
		return sessionIdString;
	}

	public void setSessionIdString(String sessionIdString) {
		this.sessionIdString = sessionIdString;
	}

	public String getIpString() {
		return ipString;
	}

	public void setIpString(String ipString) {
		this.ipString = ipString;
	}

	public String getFirstTimeString() {
		return firstTimeString;
	}

	public void setFirstTimeString(String firstTimeString) {
		this.firstTimeString = firstTimeString;
	}
}

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
@WebListener("This is My Servlet 3.0 Listener")
public class MyServletContextListener implements ServletContextListener {

	@Override
	public void contextDestroyed(ServletContextEvent arg0) {
		System.out.println("contextDestroyed");
	}

	@Override
	public void contextInitialized(ServletContextEvent arg0) {
		System.out.println("contextInitialized");
	}
}

版权声明：本文博主原创文章，博客，未经同意不得转载。