【图】JSP过滤器实现---论坛不文明语过滤功能

说明:

以下代码运行环境:jdk1.4,工具JBuilder2005,Servlet2.4,JSP2.0红色标记为关键代码.由于工程太大,我在这里只放有XML文件、JSP文件、过滤器具体内容用论坛回复。顺序为：JSP文件---过滤器---XML文件.

过滤器

/title
/head
body bgcolor="#ffffff"
h1

准备过滤

/h1
h1${pageScope.user}/h1
form method="post" action="Example1.jsp"
br
input type="text" name="user" /
br
input type="submit" name="Submit" value="Submit"
input type="reset" value="Reset"
/form
/body
/html

文字

%@ page contentType="text/html; charset=GBK" %
%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %
%
Object str= request.getAttribute("user");
pageContext.setAttribute("user",str);
%
html
head
title
过滤器
/title
/head
body bgcolor="#ffffff"
h1
准备过滤
package com.lgx.filtertext.dao;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class Filter1 extends HttpServlet implements Filter {
   private FilterConfig filterConfig;
   //Handle the passed-in FilterConfig
   public void init(FilterConfig filterConfig) throws ServletException {
       this.filterConfig = filterConfig;
   }

   //Process the request/response pair
   public void doFilter(ServletRequest request, ServletResponse response,
                        FilterChain filterChain) {
       String[] strUser = {"江泽民同志", "胡锦涛同志", "奶奶的", "我拷", "他XX的"};
       String str = "";

       try {
           request.setCharacterEncoding("GBK");
           HttpServletRequest hsrq = (HttpServletRequest) request;
           String user = hsrq.getParameter("user");

if (user == null || user.equals("")) {

           } else {
               StringBuffer sb = new StringBuffer(user);
               for (int i = 0; i strUser.length; i++) {
                   str = strUser[i];
                   if (sb.indexOf(str) == -1) {
                       hsrq.setAttribute("user", sb.toString());
                   } else {
                       sb.replace(sb.indexOf(str), sb.indexOf(str) + 3, "xxx");
                       hsrq.setAttribute("user", sb.toString());
                   }

               }
           }
           filterChain.doFilter(request, response);
       } catch (ServletException sx) {
           filterConfig.getServletContext().log(sx.getMessage());
       } catch (IOException iox) {
           filterConfig.getServletContext().log(iox.getMessage());
       }
   }

   //Clean up resources
   public void destroy() {
   }
}

注：此“XML”代码是在运行时出现的，

？xml version="1.0" encoding="UTF-8"？
web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" version="2.4"
display-nameWeb/display-name
filter
   filter-namefilter1/filter-name
   filter-classcom.lgx.filtertext.dao.Filter1/filter-class
/filter
filter-mapping
   filter-namefilter1/filter-name
   url-pattern/*/url-pattern
/filter-mapping
servlet
   descriptionAdded by JBuilder to compile JSPs with debug info/description
   servlet-namedebugjsp/servlet-name
   servlet-classorg.apache.jasper.servlet.JspServlet/servlet-class
   init-param
     param-nameclassdebuginfo/param-name
     param-valuetrue/param-value
   /init-param
   load-on-startup3/load-on-startup
/servlet
servlet-mapping
   servlet-namedebugjsp/servlet-name
   url-pattern*.jsp/url-pattern
/servlet-mapping
/web-app