五个有用的过滤器.doc

五个有用的过滤器五个有用的过滤器出自： 代码五个有用的过滤器 一、使浏览器不缓存页面的过滤器 import javax.servlet.*; import javax.servlet.http.HttpServletResponse; import java.io.IOException; /** * 用于的使 Browser 不缓存页面的过滤器 */ public class ForceNoCacheFilter implements Filter { public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException { ((HttpServletResponse) response).setHeader(“Cache-Control“,“no-cache“); ((HttpServletResponse) response).setHeader(“Pragma“,“no-cache“); ((HttpServletResponse) response).setDateHeader (“Expires“, -1); filterChain.doFilter(request, response); } public void destroy() { } public void init(FilterConfig filterConfig) throws ServletException { } } 二、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)) 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()); } } } } 三、字符编码的过滤器 import javax.servlet.*; import java.io.IOException; /** * 用于设置 HTTP 请求字符编码的过滤器，通过过滤器参数encoding 指明使用何种字符编码,用于处理 Html Form 请求参数的中文问题 */ public class CharacterEncodingFilter implements Filter { protected FilterConfig filterConfig = null; protected String encoding = ““; public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { if(encoding != null) servletRequest.setCharacterEncoding(encoding); filterChain.doFilter(servletRequest, servletResponse); } public void destroy() { filterConfig = null; encoding = null; } public void init(FilterConfig filterConfig) throws ServletException { this.filterConfig = filterConfig; this.encoding = filterConfig.getInitParameter(“encoding“); } } 四、资源保护过滤器 package catalog.view.util; import javax.servlet.Filter; import javax.servlet.FilterConfig; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.FilterChain; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import java.io.IOException; import java.util.Iterator; import java.util.Set; import java.util.HashSet; // import mons.logging.Log; import mons.logging.LogFactory; /** * This Filter class handle the security of the application. * * It should be configured inside the web.xml. * * @author Derek Y. Shen */ public class SecurityFilter implements Filter { //the login page uri private static final String LOGIN_PAGE_URI = “login.jsf“; //the logger object private Log logger = LogFactory.getLog(this.getClass()); //a set of restricted resources private Set restrictedResources; /** * Initializes the Filter. */ public void。