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1、五个有用的过滤器五个有用的过滤器出自：http:/ 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 respon
2、se, 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, respon
3、se); 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
4、.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 CheckL
5、oginFilter 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)
6、throws IOException, ServletException HttpServletRequest request = (HttpServletRequest) servletRequest; HttpServletResponse response = (HttpServletResponse) servletResponse; HttpSession session = request.getSession(); if(sessionKey = null) filterChain.doFilter(request, response); return; if(!checkReq
7、uestURIIntNotFilterList(request) return; filterChain.doFilter(servletRequest, servletResponse); public void destroy() notCheckURLList.clear(); private boolean checkRequestURIIntNotFilterList(HttpServletRequest request) String uri = request.getServletPath() + (request.getPathInfo() = null ? “ : reque
8、st.getPathInfo(); return notCheckURLList.contains(uri); public void init(FilterConfig filterConfig) throws ServletException this.filterConfig = filterConfig; redirectURL = filterConfig.getInitParameter(“redirectURL“); sessionKey = filterConfig.getInitParameter(“checkSessionKey“); String notCheckURLL
9、istStr = 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.IOExcep
10、tion; /* * 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
11、, 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 Se
12、rvletException 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.ser
13、vlet.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 s
14、ecurity 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
