监听器实现网站计数并获取用户信息

当然第一个类应该是用户的实体类

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;
	}
}

JSP中的代码如下

当前访问人数:<%=request.getServletContext().getAttribute("number") %><br/>
详细信息如下所示：<br/>
<%! int i=0; %>
<%
i=0;
ArrayList<User> userList=(ArrayList<User>)request.getServletContext().getAttribute("userList");
if(userList!=null){
	for(User user: userList){
%>
第<%= (++i) %>Session的信息：<%= user.getSessionIdString() %><br/>
时间：<%= user.getFirstTimeString() %><br/>
IP: <%= user.getIpString() %><br/>

<%	
	}
}

%>

监听器通过监听会话的个数，就可以判断登入的人数，但是不能够获取到IP的信息，只能通过request监听获取，因此要实现两个监听类（注意监听加上注解就可以了，不用到web.xml中去添加）

session监听类

import javax.servlet.annotation.WebListener;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

@WebListener
public class HttpSession1 implements HttpSessionListener {

	private int number=0;
	@Override
	public void sessionCreated(HttpSessionEvent arg0) {
		// TODO Auto-generated method stub
		number++;
		//通过获取会话来获取application，将number变量设置进去，没有直接获取application方法
		arg0.getSession().getServletContext().setAttribute("number", number);
		//没有获取ip地址的方法，只能到request的监听器中去调用arg0.getServletRequest 
	}

	@Override
	public void sessionDestroyed(HttpSessionEvent arg0) {
		// TODO Auto-generated method stub
		number--;
		arg0.getSession().getServletContext().setAttribute("number", number);
	}

}

request监听类

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.entity.User;
@WebListener
public class HttpRequest1 implements ServletRequestListener {

	private ArrayList<User> userList;
	
	@Override
	public void requestDestroyed(ServletRequestEvent arg0) {
		// TODO Auto-generated method stub

	}

	@Override
	public void requestInitialized(ServletRequestEvent arg0) {
		// TODO Auto-generated method stub
		
		userList=(ArrayList<User>)arg0.getServletContext().getAttribute("userList");
		if(userList==null){
			userList=new ArrayList<User>();
		}

		//获取到了request
		HttpServletRequest request=(HttpServletRequest)arg0.getServletRequest();
		
		
		//获取每一个会话的ID
		String sessionIdString=request.getSession().getId();
		
		if(getUserBySessionId(sessionIdString)){
			User user=new User();
			user.setSessionIdString(sessionIdString);
			user.setFirstTimeString(new SimpleDateFormat("yyyy-MM-dd:mm:ss").format(new Date()));
			user.setIpString(request.getRemoteAddr());
			
			userList.add(user);
			
			arg0.getServletContext().setAttribute("userList", userList);
		}

	}
	 
	private boolean getUserBySessionId(String s){
		
		for(User user: userList){
			if(s.equals(user.getSessionIdString())){
				return false;
			}
		}
		return true;
	}
}