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使用简单标签解决防盗链问题

2011-11-09 21:34 375 查看

使用简单标签解决防盗链问题
一思路分析

   防盗链就是不让自己的网站通过别的网站访问，而应该是通过自己网站的首页再访问自己网站的东西

    下面创建了两个jsp页面，一个java页面，jsp页面是为了模拟首页和点击首页进去的网页。Java页面是编写标签处理器

二源码

1.创建标签处理器

类名为RefererTag.java

public class RefererTag extends SimpleTagSupport {
    private String site;
    private String page;

    public void setSite(String site) {
       this.site = site;
    }
    public void setPage(String page) {
       this.page = page;
    }

    @Override
    public void doTag() throws JspException, IOException {
       // 获取request对象
       JspContext jc = this.getJspContext();
       PageContext pc = (PageContext) jc;
       HttpServletRequest request = (HttpServletRequest)pc.getRequest();

       HttpServletResponse response = (H
4000
ttpServletResponse)pc.getResponse();

       String referer = request.getHeader("referer");

       if (referer == null || !referer.startsWith("http://localhost")) {
           // 跳转到首页
           //获取地址的完整路径
           if (page.startsWith(request.getContextPath())) {
              response.sendRedirect(page);
           } else if (page.startsWith("/")) {//获取加/的路径
              response.sendRedirect(request.getContextPath() + page);
           } else {
              //最不完整的路径
              response.sendRedirect(request.getContextPath() + "/" + page);
           }
           // 不运行一下的代码
           throw new SkipPageException();
       }
    }

2．部署tld文件为：dhw.tld

<?xml version="1.0"encoding="UTF-8"?>
<!DOCTYPE taglib PUBLIC "-//SunMicrosystems, Inc.//DTD JSP Tag Library 1.2//EN"
                        "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib>
    <tlib-version>1.0</tlib-version>
    <jsp-version>1.2</jsp-version>
    <short-name>dhw</short-name>
    <uri>http://www.dhw.com</uri>
    <tag>
       <name>referer</name>
       <tag-class>com.hbsi.web.tag.project.RefererTag</tag-class>
       <body-content>empty</body-content>
       <attribute>
           <name>site</name>
           <required>true</required>
           <rtexprvalue>true</rtexprvalue>
       </attribute>
       <attribute>
           <name>page</name>
           <required>true</required>
           <rtexprvalue>true</rtexprvalue>
       </attribute>
    </tag>
</taglib>
3. 创建TestReferer.jsp页面和index.jsp页面（首页）

(1)TestReferer.jsp---是应该通过首页访问到的页面，如果没有经过首页就访问，则会跳转到首页，在标签处理器中判断
<%@ page language="java" import="java.util.*"pageEncoding="utf-8"%>
<%@ taglib uri="http://www.dhw.com" prefix="dhw"%>

<dhw:referer site="http://localhost"page="/index.jsp"/>
<%
String path =request.getContextPath();
String basePath =request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">

    <title>My JSP 'TestReferer.jsp' starting page</title>

    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control"content="no-cache">
    <meta http-equiv="expires"content="0">
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    
</head>

<body>明星信息----------------
</body>
</html>
（2）index.jsp----首页

<%@ page language="java" import="java.util.*"pageEncoding="utf-8"%>
<%
String path =request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">

    <title>My JSP 'index.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control"content="no-cache">
    <meta http-equiv="expires"content="0">
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    
</head>
<body>
    This is my JSP page. <br>
    <a href="/CustomerTagDemo/example/TestReferer.jsp">明星档案</a>
</body>
</html>

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标签： string jsp html java import encoding

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