java检测在线用户_java检测用户是否登陆的过滤器

java检测用户是否登陆的过滤器。

import javax.servlet.*;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import java.util.List;

import java.util.ArrayList;

import java.util.StringTokenizer;

import java.io.IOException;

/**

* 用于检测用户是否登陆的过滤器，如果未登录，则重定向到指的登录页面

* 配置参数

* checkSessionKey 需检查的在 Session 中保存的关键字

* redirectURL 如果用户未登录，则重定向到指定的页面，URL不包括 ContextPath

* notCheckURLList 不做检查的URL列表，以分号分开，并且 URL 中不包括 ContextPath

*/

public class CheckLoginFilter implements Filter

{

protected FilterConfig filterConfig = null;

private String redirectURL = null;

private List notCheckURLList = new ArrayList();

private String sessionKey = null;

public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException

{

HttpServletRequest request = (HttpServletRequest) servletRequest;

HttpServletResponse response = (HttpServletResponse) servletResponse;

HttpSession session = request.getSession();

if(sessionKey == null)

{

filterChain.doFilter(request, response); return;

}

if((!checkRequestURIIntNotFilterList(request)) && session.getAttribute(sessionKey) == null)

{

response.sendRedirect(request.getContextPath() + redirectURL);

return;

}

filterChain.doFilter(servletRequest, servletResponse);

}

public void destroy()

{

notCheckURLList.clear();

}

private boolean checkRequestURIIntNotFilterList(HttpServletRequest request)

{

String uri = request.getServletPath() + (request.getPathInfo() == null ? “” : request.getPathInfo());

return notCheckURLList.contains(uri);

}

public void init(FilterConfig filterConfig) throws ServletException

{

this.filterConfig = filterConfig;

redirectURL = filterConfig.getInitParameter(“redirectURL”);

sessionKey = filterConfig.getInitParameter(“checkSessionKey”);

String notCheckURLListStr = filterConfig.getInitParameter(“notCheckURLList”);

if(notCheckURLListStr != null)

{

StringTokenizer st = new StringTokenizer(notCheckURLListStr, “;”);

notCheckURLList.clear();

while(st.hasMoreTokens())

{

notCheckURLList.add(st.nextToken());

}

}

}

}