HTML特殊字符过滤器

package com.pdsu.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;



/**

* 类说明：HTML特殊字符过滤器

*

* @author 作者: LiuJunGuang

* @version 创建时间：2011-11-18 下午07:36:44

*/

public class HTMLCharacterFilter implements Filter {



public void init(FilterConfig filterConfig) throws ServletException {



}



public void doFilter(ServletRequest req, ServletResponse resp,

FilterChain chain) throws IOException, ServletException {

HttpServletRequest request = (HttpServletRequest) req;

HttpServletResponse response = (HttpServletResponse) resp;

chain.doFilter(new HTMLCharacterRequest(request), response);

}



public void destroy() {



}

}



// html特殊字符处理类

class HTMLCharacterRequest extends HttpServletRequestWrapper {



public HTMLCharacterRequest(HttpServletRequest request) {

super(request);

}



@Override

public String getParameter(String name) {

return filter(super.getParameter(name));

}

@Override

public String[] getParameterValues(String name) {

String[] values = super.getParameterValues(name);

if (values == null || values.length == 0)

return values;

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

String str = values[i];

values[i] = filter(str);

}

return values;

}

/**

* 对特殊的html字符进行编码

*

* @param message

* @return

*/

private String filter(String message) {



if (message == null)

return (null);



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

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

StringBuilder result = new StringBuilder(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());



}

}

在web.xml中添加如下内容：

[html] view
plaincopy





<!-- HTML特殊字符过滤器 -->

<filter>

<filter-name>HTMLFiter</filter-name>

<filter-class>com.pdsu.filter.HTMLCharacterFilter</filter-class>

</filter>

<filter-mapping>

<filter-name>HTMLFiter</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>