- 技术人生
- filter过滤器实现过滤非法文字
1.首先创建一个java web工程,目录如下:
说明: WorldFilter.java -> 过滤非法字符的过滤器 IllegalText.properties - >需要过滤的非法字符
2. WorldFilter.java 代码
package com;
import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.util.Collection; import java.util.Iterator; import java.util.Properties; import java.util.Random;
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.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper;
public class WorldFilter implements Filter{
Properties ps = new Properties(); //properties 属性文件 Collection con = null; //非法文字集合(从properties属性文件中读取出来) private String encoding; //字符编码 private String[] charWorld = new String[]{"~","@","#","$","%","^","&","*"}; //将非法文字替换成 随机字符 Random input = new Random(); //随机产生器(为上面的随机字符提供下标)
public void init(FilterConfig filterConfig) throws ServletException { //获取字符编码字符串,需要web.xml文件中配置 encoding = filterConfig.getInitParameter("encoding"); try { //读取properties配置文件 InputStream in = filterConfig.getServletContext().getResourceAsStream("/WEB-INF/IllegalText.properties"); ps.load(in); con = ps.values(); //得到properties中的所有value值,存入collection集合中 } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { // TODO Auto-generated method stub if(encoding != null){ request.setCharacterEncoding(encoding); //设置 request字符编码 request = new Request((HttpServletRequest)request); response.setContentType("text/html;charset=" + encoding); //设置response字符编码 } chain.doFilter(request, response); } public void destroy() { // TODO Auto-generated method stub } //内部类 为了重写request的getParameter 和 getParameterValues class Request extends HttpServletRequestWrapper{
public Request(HttpServletRequest request) { super(request); }
@Override public String getParameter(String name) {//返回值之前 先进行过滤 return filter(super.getParameter(name)); }
@Override public String[] getParameterValues(String name) { //返回值之前 先进行过滤 // TODO Auto-generated method stub String[] values = super.getParameterValues(name); for (int i = 0; i < values.length; i++) { values[i] = filter(values[i]); } return values; } } public String filter(String param){ //过滤非法字符的方法 try { if(param != null && param.length()>0){ //保证传入的字符串不为空和空字符串 Iterator it = con.iterator(); //迭代器 可以 把collection中的值一条一条的读出来 if(con != null ){ //集合要被初始化 while (it.hasNext()) { //判断集合里是否还有值 String value = (String)it.next(); //取出该值 if(param.indexOf(value) != -1){ param = param.replace(value, charWorld[input.nextInt(8)]); //对非法字符词语进行替换 } } } } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return param; } }
说明: 本人纯属新手,所以某些注释可能一点都不专业,不过我觉得挺简单易懂的 呵呵
3. IllegalText.properties (三个非法文字为 靠 混蛋 fuck 自己可随意添加)
1=/u9760 2=/u6DF7/u86CB 3=fuck
4. web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <filter> <filter-name>worldFilter</filter-name> <filter-class>com.WorldFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>worldFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
5. index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <html> <head></head> <body> <form action="result.jsp" method="post"> <textarea cols="30" rows="10" name="message"> </textarea> <input type="submit" value="提交"> </form> </body> </html>
5. index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <html> <head></head> <body> <% String message = request.getParameter("message"); %> 你刚刚输入的东东为: <%=message %> </body> </html>
说明: 这里为了方便测试 所以加上了<% %> 呵呵!
