java 过滤器
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- java 代码
- 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;
-
-
- 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;
-
-
- 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)) && session.getAttribute(sessionKey) == null)
- {
- response.sendRedirect(request.getContextPath() + redirectURL);
- 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;
-
-
- 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 org.apache.commons.logging.Log;
- import org.apache.commons.logging.LogFactory;
-
-
- public class SecurityFilter implements Filter {
- private static final String LOGIN_PAGE_URI = "login.jsf";
-
- private Log logger = LogFactory.getLog(this.getClass());
-
- private Set restrictedResources;
-
-
- public void init(FilterConfig filterConfig) throws ServletException {
- this.restrictedResources = new HashSet();
- this.restrictedResources.add("/createProduct.jsf");
- this.restrictedResources.add("/editProduct.jsf");
- this.restrictedResources.add("/productList.jsf");
- }
-
-
- public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
- throws IOException, ServletException {
- this.logger.debug("doFilter");
-
- String contextPath = ((HttpServletRequest)req).getContextPath();
- String requestUri = ((HttpServletRequest)req).getRequestURI();
-
- this.logger.debug("contextPath = " + contextPath);
- this.logger.debug("requestUri = " + requestUri);
-
- if (this.contains(requestUri, contextPath) && !this.authorize((HttpServletRequest)req)) {
- this.logger.debug("authorization failed");
- ((HttpServletRequest)req).getRequestDispatcher(LOGIN_PAGE_URI).forward(req, res);
- }
- else {
- this.logger.debug("authorization succeeded");
- chain.doFilter(req, res);
- }
- }
-
- public void destroy() {}
-
- private boolean contains(String value, String contextPath) {
- Iterator ite = this.restrictedResources.iterator();
-
- while (ite.hasNext()) {
- String restrictedResource = (String)ite.next();
-
- if ((contextPath + restrictedResource).equalsIgnoreCase(value)) {
- return true;
- }
- }
-
- return false;
- }
-
- private boolean authorize(HttpServletRequest req) {
-
-
-
-
- }
- }