防盗链

原理：判断http消息头中的referer是否为空或者是否不为localhost

 

代码放在：jsp文件引入，因为所有数据都是以jsp页面的形式展示出来的

<%@page import="com.qipai.referer_module.Request_referer" %> //引入包

<%

Request_referer Rr=new Request_referer();

Rr.Referer(request, response);

%>

 

 

代码：

 //这个函数属于Request_referer 类 

 public void Referer(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{

                   //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");

 

}

         }