struts标签库 Web App struts框架里实现Filter

Web App struts框架里实现Filter  

　　 web xml里添加filter配置信息 　　<filter>　　<filter name>Authentication</filter name>　　<filter class>　　limas web filters AuthenticationFilter　　</filter class>　　<init param>　　<param name>onError</param name>　　<param value>/pages/index jsp</param value>　　</init param>　　</filter>　　<filter mapping>　　<filter name>Authentication</filter name>　　<url pattern>/protect/*</url pattern>　　</filter mapping>　　<filter class>定义使用limas web filters AuthenticationFilter类执行过滤Action 　　<init param>当验证失败后Forward到/pages/index jsp　　<filter mapping>只有当地址包括/protect/时运行filter类　　　　 实现limas web filters AuthenticationFilter　　package limas web filters;　　import java io IOException;　　import javax servlet RequestDispatcher;　　import javax servlet ServletException;　　import javax servlet *;　　import javax servlet Filter;import javax servlet FilterChain;　　import javax servlet FilterConfig;　　import limas web bean UserBean;　　import javax servlet ServletRequest;　　import javax servlet ServletResponse;import apache struts Globals;　　import apache struts action *;　　import nstants Constants;　　/**　　* Filter implementation for user authentication 必须实现Filter接口　　* @author tyrone * @version $Id: AuthenticationFilter java v 　　*/public class AuthenticationFilter implements Filter{　　/**　　* filterConfig will store the reference of FilterConfig　　*/　 private FilterConfig filterConfig;　　private String onErrorUrl;　　/**　　* store the reference of the FilterConfig 　　* @param config FilterConfig object　　* @throws ServletException　　*/　 public void init(FilterConfig config) throws ServletException　　{//获得验证失败forward地址　　filterConfig = config;　　onErrorUrl=filterConfig getInitParameter( onError );　　if (onErrorUrl==null || equals(onErrorUrl)){　　onErrorUrl= /pages/index jsp ;　　}　　}　　/**　　* User Authentication is　done If User is authenticated successful then　　* control is transferred to logon URI　　* @param ServletRequest Request　　* @param ServletRequest Response　　* @param FilterChain Filter Chain　　* @throws ServletException IOException　　*/　 public void doFilter(ServletRequest request ServletResponse response FilterChain next)　　throws IOException ServletException　　{　　HttpServletRequest Request = (HttpServletRequest)request;　　HttpServletResponse Response=(HttpServletResponse)response;　　// Current session　　HttpSession Session = ();　　//Session里是否有用户信息 　　if ((Constants USER_KEY) == null)　　{　　ActionErrors errors=new ActionErrors();　　errors add(ActionErrors GLOBAL_ERROR 　　new ActionError( error authentication ));　　(Globals ERROR_KEY errors);　　//没有 验证失败forward到/pages/index jsp　　(onErrorUrl) forward(Request Response);　　}else//成果过滤Action结束　　next doFilter(request response);　　}　　/**　　* destroy() method is called by the servlet container　　*/　 public void destroy()　　{　　}　　} lishixinzhi/Article/program/Java/ky/201311/28400