filter写的登陆过滤器

package com.yang.juping;

import java.io.IOException; 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.HttpServlet;

import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class Juping implements Filter{ FilterConfig config=null;

public void init(FilterConfig config) throws ServletException{

this.config=config; }

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException{ System.out.println(1111);

HttpServletRequest req = (HttpServletRequest) request; //把request,response转换为HttpServletRequest

HttpServletResponse res = (HttpServletResponse) response; res.sendRedirect(\"index.jsp\");//指定要跳转的页面 }

public void destroy(){ } }

在web.xml写入

//当访问/index.jsp时，就转向com.yang.juping.Juping

jup

com.yang.juping.Juping

jup /index.jsp

2：网上找的还没用过。

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; /**

* 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\ ((HttpServletResponse) response).setHeader(\"Pragma\ ((HttpServletResponse) response).setDateHeader (\"Expires\ 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)) && 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; /**

* 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 org.apache.commons.logging.Log;

import org.apache.commons.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 init(FilterConfig filterConfig) throws ServletException { this.restrictedResources = new HashSet();

this.restrictedResources.add(\"/createProduct.jsf\"); this.restrictedResources.add(\"/editProduct.jsf\"); this.restrictedResources.add(\"/productList.jsf\"); } /**

* Standard doFilter object. */

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) {

//处理用户登录 /* UserBean user (UserBean)req.getSession().getAttribute(BeanNames.USER_BEAN);

if (user != null && user.getLoggedIn()) { //user logged in return true; } else {

return false; }*/ } }

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