javaWeb 使用jsp标签进行防盗链

时间：2023-12-04 18:55:14
/**

 * 1.新建类继承SimpleTagSupport

 *     新建２个属性, 添加对应的set方法

 *     覆盖doTag()方法

 */

import java.io.IOException;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.jsp.JspException;

import javax.servlet.jsp.PageContext;

import javax.servlet.jsp.SkipPageException;

import javax.servlet.jsp.tagext.SimpleTagSupport;

public class RefererTag extends SimpleTagSupport {

    private String webSite;

    private String jumpPage;

    public void setWebSite(String webSite) {

        this.webSite = webSite;

    }

    public void setJumpPage(String jumpPage) {

        this.jumpPage = jumpPage;

    }

    @Override

    public void doTag() throws JspException, IOException {

        PageContext pageContext = (PageContext) this.getJspContext();

        HttpServletRequest request = (HttpServletRequest) pageContext.getRequest();

        HttpServletResponse response = (HttpServletResponse) pageContext.getResponse();

        String webRoot = request.getContextPath();

        // 得到 referer

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

        if (referer == null || !referer.startsWith(webSite)) { // 是盗链者

            if (jumpPage.startsWith(webRoot)) { // "/web/index.jsp"

                response.sendRedirect(jumpPage);

            } else if (jumpPage.startsWith("/")) { // "/index.jsp"

                response.sendRedirect(webRoot + jumpPage);

            } else {// "index.jsp"

                response.sendRedirect(webRoot + "/" + jumpPage);

            }

            throw new SkipPageException();// 如果是盗链者，就抛出这个异常

        }

    }

}
<?xml version="1.0" encoding="UTF-8" ?>

<!-- 文件名 /WEB-INF/referer.tld -->

<taglib xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"

    version="2.0">

    <tlib-version>1.0</tlib-version>

    <short-name>anyName</short-name><!-- 这个值可以任意设置 -->

    <uri>anyUri</uri><!-- 这个Uri可以任意设置，但是不要与别的 .tld 文件相同 -->

    <tag>

        <name>referer</name>

        <tag-class>de.bvb.web.tag.RefererTag</tag-class>

        <body-content>empty</body-content> <!-- 不要标签体 -->

        <attribute>

            <name>webSite</name><!-- 需要添加前面设置的２个属性 -->

            <required>true</required><!-- required表示是否必须 -->

            <rtexprvalue>true</rtexprvalue><!-- rtexprvalue表示属性的值是否可以使用el表达式 -->

        </attribute>

        <attribute>

            <name>jumpPage</name>

            <required>true</required>

            <rtexprvalue>true</rtexprvalue>

        </attribute>

    </tag>

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

<%@taglib prefix="referer" uri="/WEB-INF/referer.tld"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<!-- 3.设置好标签库以后添加下面这行标签就可以进行防盗链了。

webSite表示不设置防盗链的站点，jumpPage表示发现盗链以后跳转的页面 -->

<referer:referer webSite="http://localhost" jumpPage="index.jsp" />

<html>

<head>

<title>通过jsp标签进行防盗链</title>

</head>

<body>某某某的文章</body></html>

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