过滤器实现单个用户的登录控制

实现一个简单的登录控制过滤器，可以控制对哪些页面不做过滤，不满足条件的直接跳转到指定页面。

需要在两个地方配置

1：web.xml

2: CheckLoginFilter.java

1：web.xml （见图一和图二）

图一

图二

2：checkLoginFilter

package com.wsbalance.filter;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import java.util.StringTokenizer;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import com.wsbalance.pojo.Admin;

/**

* 实现登入控制

* @author cs

* @version1.0

*

*/

public class CheckLoginFilter implements Filter {

protected FilterConfig filterConfig = null;

private String redirectURL = null;

private List notCheckURLList = new ArrayList();

private String sessionKey = null;

/**

*

* @param servletRequest

* @param servletResponse

*

*/

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

{

HttpServletRequest request = (HttpServletRequest) servletRequest;

HttpServletResponse response = (HttpServletResponse) servletResponse;

HttpSession session = request.getSession();

Admin admin=(Admin)session.getAttribute(sessionKey);

if(sessionKey==null)

{

filterChain.doFilter(request, response);

return;

}

if((!checkRequestURIIntNotFilterList(request)) && (admin == null))

{

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

return;

}

filterChain.doFilter(servletRequest, servletResponse);

}

/**

* 注销

*/

public void destroy()

{

notCheckURLList.clear();

}

private boolean checkRequestURIIntNotFilterList(HttpServletRequest request)

{

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

return notCheckURLList.contains(uri);

}

/**

* 初始化最先调用

*

*/

public void init(FilterConfig filterConfig) throws ServletException

{

this.filterConfig = filterConfig;

redirectURL = filterConfig.getInitParameter("redirectURL"); //获得重定向地址

sessionKey = filterConfig.getInitParameter("checkSessionKey");//获得关键字

String notCheckURLListStr = filterConfig.getInitParameter("notCheckURLList");

if(notCheckURLListStr != null)

{

StringTokenizer st = new StringTokenizer(notCheckURLListStr, ";"); //通过;进行分割

notCheckURLList.clear();

while(st.hasMoreTokens())

{

notCheckURLList.add(st.nextToken());//存入列表

}

}

}

}

注意修改对应的包，需要将web.xml中的filter-class 改成checkLoginFilter.java所在的包，

admin 

中的admin 代表登录后存入session中的值，需改成当前系统登录的对象