防盗链

                   //设置浏览器以什么编码打开

                   response.setCharacterEncoding("utf-8");

                   response.setContentType("text/html;utf-8");

                   PrintWriter out=response.getWriter();

                   //获取请求头

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

                   //判断这个请求头是否为空，或者这个请求头是否不为localhost

                   if(referer == null || !referer.startsWith("http://localhost")){

                            out.println("请登录");

                            response.sendRedirect("http://localhost:8080/QiPaiProject/Login.jsp");

}

         }