servlet监听器统计在线人数

1.登录用户信息类

import java.util.Vector;

public class UserInfoList {

    private static UserInfoList user = new UserInfoList();
    private Vector vector = null;

    public UserInfoList() {
        this.vector = new Vector();
    }

    public static UserInfoList getInstance() {
        return user;
    }

    public boolean addUserInfoList(String user) {
        if (user != null) {
            this.vector.add(user);
            return true;
        } else {
            return false;
        }
    }

    public Vector getList() {
        return this.vector;
    }

    public void removeUserInfo(String user) {
        if (user != null) {
            vector.removeElement(user);
        }
    }
}

public class UserInfoList