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java web Decorator模式包装request对象实现html标签转义功能

2016-08-19 09:25 453 查看

package me.gacl.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;

/**

* @ClassName: HtmlFilter

* @Description: html转义过滤器

* @author: 孤傲苍狼

* @date: 2014-9-2 下午11:28:41

*

*/

public class HtmlFilter implements Filter {

public void doFilter(ServletRequest req, ServletResponse resp,

FilterChain chain) throws IOException, ServletException {



HttpServletRequest request = (HttpServletRequest) req;

HttpServletResponse response = (HttpServletResponse) resp;

MyHtmlRequest myrequest = new MyHtmlRequest(request);

chain.doFilter(myrequest, response);



}



public void destroy() {



}



public void init(FilterConfig filterConfig) throws ServletException {



}

}

/**

* @ClassName: MyHtmlRequest

* @Description: 使用Decorator模式包装request对象，实现html标签转义功能

* @author: 孤傲苍狼

* @date: 2014-9-2 下午11:29:09

*

*/

class MyHtmlRequest extends HttpServletRequestWrapper {

private HttpServletRequest request;

public MyHtmlRequest(HttpServletRequest request) {

super(request);

this.request = request;

}

/* 覆盖需要增强的getParameter方法

* @see javax.servlet.ServletRequestWrapper#getParameter(java.lang.String)

*/

@Override

public String getParameter(String name) {

String value = this.request.getParameter(name);

if (value == null) {

return null;

}

//调用filter转义value中的html标签

return filter(value);

}

/**

* @Method: filter

* @Description: 过滤内容中的html标签

* @Anthor:孤傲苍狼

* @param message

* @return

*/

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();

}
}



<filter>

<filter-name>HtmlFilter</filter-name>

<filter-class>me.gacl.web.filter.HtmlFilter</filter-class>

</filter>



<filter-mapping>

<filter-name>HtmlFilter</filter-name>

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

</filter-mapping>

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML>

<html>

<head>

<title>html过滤器测试</title>

</head>



<body>

<form action="${pageContext.request.contextPath}/servlet/ServletDemo2" method="post">

留言:

<textarea rows="8" cols="70" name="message">

<script type="text/javascript">

while(true){

alert("死循环了，我会不停地弹出了");

}

</script>

<a href="http://www.cnblogs.com">访问博客园</a>

</textarea>

<input type="submit" value="发表">

</form>

</body>

</html>

package me.gacl.web.controller;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class ServletDemo2 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//获取用户输入的内容

String message = request.getParameter("message");

response.getWriter().write("您上次的留言是：<br/>" + message);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

}

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标签： java web

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