一个小小的防盗链图片的filter

public class ImageRedirectFilter implements Filter {

 public void init(FilterConfig config) throws ServletException {
 }

 public void doFilter(ServletRequest req, ServletResponse res,
   FilterChain chain) throws IOException, ServletException {

  HttpServletRequest request = (HttpServletRequest) req;
  HttpServletResponse response = (HttpServletResponse) res;

  // 禁止缓存
  response.setHeader("Cache-Control", "no-store");
  response.setHeader("Pragrma", "no-cache");
  response.setDateHeader("Expires", 0);

  // 链接来源地址
  String referer = request.getHeader("referer");
  System.out.println("refer is"+referer);

  if (referer == null || !referer.contains(request.getServerName())) {

   /**
    * 如果 链接地址来自其他网站，则返回错误图片
    */
   request.getRequestDispatcher("/error.gif").forward(request,
     response);

  } else {

   /**
    * 图片正常显示
    */
   chain.doFilter(request, response);
  }

 }

 public void destroy() {
 }
}

 

 

web.xml:

<filter-mapping>
  <filter-name>imageRedirectFilter</filter-name>
    <url-pattern>/upload/images/*</url-pattern>
 </filter-mapping>

<script type="text/javascript"></script>