package cn.lfd.web.filter;

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.HttpServletRequest;

import javax.servlet.http.HttpServletRequestWrapper;

import javax.servlet.http.HttpServletResponse;

/*

* 用过滤器让全站html标签转义输出

*/

public class HtmlFilter implements Filter {

@Override

public void destroy() {

}

@Override

public void doFilter(ServletRequest req, ServletResponse resp,

FilterChain chain) throws IOException, ServletException {

HttpServletRequest request = (HttpServletRequest) req;//对ServletResponse进行强转

HttpServletResponse response = (HttpServletResponse) resp;

MyHtmlRequest MyRequest = new MyHtmlRequest(request);//new 出一个增强后的request

chain.doFilter(MyRequest, response);

}

@Override

public void init(FilterConfig filterConfig) throws ServletException {

// TODO Auto-generated method stub

}

}

//增强HttpServletRequest方法的getParameter方法

class MyHtmlRequest extends HttpServletRequestWrapper {

public MyHtmlRequest(HttpServletRequest request) {

super(request);

}

@Override

public String getParameter(String name) {//对getParameter方法进行增强

String value = super.getParameter(name);

if(value==null) {

return null;

}

return filter(value);//调用filter方法对数据进行html转义

}

public String filter(String message) {

if (message == null)

return (null);

char content[] = new char[message.length()];

message.getChars(0, message.length(), content, 0);

StringBuffer result = new StringBuffer(content.length + 50);

for (int i = 0; i < content.length; i++) {

switch (content[i]) {

case '

result.append("

break;

case '>':

result.append(">");

break;

case '&':

result.append("&");

break;

case '"':

result.append(""");

break;

default:

result.append(content[i]);

}

}

return (result.toString());

}

}

注意:

1.filter方法可以在tomcat安装目录下的\webapps\examples\WEB-INF\classes\util的HTMLFilter.java中复制过来