时间

创建AProject和BProject两个工程 

 

AProject工程

  导入依赖

     <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>

  创建页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

<img src="/img/logo.jpg" width="500px" height="300px" />

</body>
</html>

  创建ImgFilter类

package com.wn.filter;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class ImgFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("过滤器开始!!!");
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        //获取当前请求的连接地址和上一个发送请求的地址
        HttpServletRequest httprequest=(HttpServletRequest) request;
        HttpServletResponse httpresponse=(HttpServletResponse) response;
        //获取上一个发送请求的连接
        String referer = httprequest.getHeader("Referer");
        String serverName = httprequest.getServerName();
        System.out.println(referer+"	"+serverName);
        //||!referer.startsWith("http://www.aproject.com")
        if (referer==null ||!referer.contains(serverName)){
            request.getRequestDispatcher("/img/fei.png").forward(request,response);
            return;
        }
        //放行
        chain.doFilter(request,response);
    }

    @Override
    public void destroy() {
        System.out.println("过滤器销毁!!!");
    }
}

  配置web.xml文件

<!DOCTYPE web-app PUBLIC
        "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
        "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  <filter>
    <filter-name>ImgFilter</filter-name>
    <filter-class>com.wn.filter.ImgFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>ImgFilter</filter-name>
    <url-pattern>/img/*</url-pattern>
  </filter-mapping>

</web-app>

BProject工程

  创建页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

<img src="http://www.aproject.com:8080/img/logo.png" width="500px" height="300px"/>

</body>
</html>

结果测试

  

  

原文地址:https://www.cnblogs.com/wnwn/p/12259534.html