做個圖片的防盜鏈

轉至做個圖片防盜鏈

目的是，網站本身的圖片不防盜鏈，用戶上傳的圖片不許外鏈 

用戶上傳的圖片都在userfile目錄和其子目錄下面 

1. 配置filter 

<filter>
    <filter-name>jpgServlet</filter-name>
    <filter-class>
        com.djwl.core.filter.JpgFilter
    </filter-class>
</filter>
<filter-mapping>
    <filter-name>jpgServlet</filter-name>
    <url-pattern>/userfile/*</url-pattern>
</filter-mapping>

2. Filter 

package com.djwl.core.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.HttpServletResponse;

/**
 * Description: <br>
 * 2010-4-13
 * @author huxiao [email protected]
 */
public class JpgFilter implements Filter {

    @Override
    public void doFilter(ServletRequest servletrequest, ServletResponse servletresponse, FilterChain filterchain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest)servletrequest;
        HttpServletResponse response = (HttpServletResponse)servletresponse;

        //獲取請求來源
        String linkFrom = request.getHeader("referer");

        /**
         * 如果不是從本網站鏈接，則返回本網站的logo，否則正常走
         * 注意：這裏的linkFrom爲null的話也正常走。原因是，用戶如果直接輸入圖片地址的話，linkFrom爲null
         */
        if(linkFrom != null && !linkFrom.contains(request.getServerName())){
            System.out.println("盜鏈來自： "+linkFrom);
            request.getRequestDispatcher("/images/logo_red.jpg").forward(request, response);
        }else {
            filterchain.doFilter(request, response);
        }
    }

    @Override
    public void destroy() {
        // TODO Auto-generated method stub

    }

    @Override
    public void init(FilterConfig filterconfig) throws ServletException {
        // TODO Auto-generated method stub

    }

}

3. 測試 

圖片所在的是localhost1:1111，現在我用localhost1和localhost2去請求，ok的話，前者能顯示，後者顯示logo 

body部分：這裏我放了兩個圖片，前面一個是/images目錄下的，不做防盜鏈，後面的做防盜鏈 

<img src="http://localhost1:1111/images/bq_bgGreen.jpg">
<img src="http://localhost1:1111/userfile/20100405/7ef5d05bacd840e8beb8147653ad2906_81_81.jpg" />

 

 

OK，這就達到咱們的目的了