防盗链

使用防盗链要使用request的 referer这个头，这个头可以截获用户是从哪个页面点过来的，然后判断是否为本站的地址，如果不是本站的地址，就跳转到本站首页

 

package cn.test.request;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;//防盗链  http://localhost:8080/day06/servlet/ResponseDemo4public class RequestDemo4 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//referer头获取用户访问的URL地址String referer = request.getHeader("referer");if(referer==null || !referer.startsWith("http://localhost")){response.sendRedirect("/day05/index.html");return;}String data = "日记";response.getWriter().write(data);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}}