Servlet 1 http請求,響應消息頭,狀態碼盜鏈機制

時間 2019-11-17

標籤 servlet http 請求響應消息狀態機制欄目 Tomcat 简体版

原文原文鏈接

目錄:html

設置響應消息頭:refresh,實現5秒後自動跳轉 index.htmljava

設置響應消息頭狀態碼302,實現請求重定向web

判斷請求消息頭,referer,實現防盜鏈post

利用URL對象,僞造referer消息頭,破解防盜鏈機制ui

*注:Servlet在web.xml文件中有配置,注意查看url

設置響應消息頭:refresh,實現5秒後自動跳轉 index.htmlspa

package cn.itcast.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * 5秒後 自動跳轉 index.html
 * @author seawind
 *
 */
public class RefreshServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 設置refresh
        response.setHeader("refresh", "5;url=index.html");
        
        // 顯示提示信息
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().println("網頁會在5秒後 跳轉 index.html");
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }

}

設置響應消息頭狀態碼302,實現請求重定向.net

package cn.itcast.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * 完成請求 重定向
 * @author seawind
 *
 */
public class RedirectServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 設置狀態碼 302 
        response.setStatus(302);
        // 指定 重定向頁面地址
        response.setHeader("Location", "img.html");
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }

}

判斷請求消息頭,referer,實現防盜鏈3d

htmlcode

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<a href="referer">特價商品</a>
</body>
</html>

Servlet

package cn.itcast.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * 經過/referer 訪問程序
 * @author seawind
 *
 */
public class RefererServlet extends HttpServlet {

    // 處理get方式請求
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 判斷請求中referer是否存在，有效  --- 防止盜鏈
        String referer = request.getHeader("referer");
        if(referer!=null && referer.equals("http://localhost/day4/index.html")){
            // 有效
            response.setContentType("text/html;charset=gbk");
            response.getWriter().println("筆記本1000元");
        }else{
            // 無效
            response.setContentType("text/html;charset=gbk");
            response.getWriter().println("盜鏈真無恥！");
        }
    }

    // 處理post方式請求
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }

}

利用URL對象,僞造referer消息頭,破解防盜鏈機制

package cn.itcast.client;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

public class URLClient {
    public static void main(String[] args) throws IOException {
        // 創建訪問目標URL對象
        URL url = new URL("http://localhost/day4/referer");
        // 創建目標URL鏈接
        URLConnection urlConnection = url.openConnection();
        // 僞造referer
        urlConnection.addRequestProperty("referer", "http://localhost/day4/index.html");
        
        // 抓取響應內容
        byte[] buf = new byte[8192];
        int len = urlConnection.getInputStream().read(buf);
        
        // 輸出內容
        System.out.println(new String(buf,0,len));
    }
}