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）
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，
<param-value>admin</param-value>
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
