java request 防止盗链

package cn.com;  
  
import java.io.IOException;  
import javax.servlet.ServletException;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
  
public class RequestPreventThreif extends HttpServlet {  
    private static final long serialVersionUID = 1L;  
         
   //防盗链：用于保护自己独有的消息，防止被其他的网站直接连接浏览，利于保护自己的信息  
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
        String referer=request.getHeader("referer");  
        if(referer==null||!referer.startsWith("http://localhost"))  
        {  
            response.sendRedirect("/Request/Index.html");  
            return;  
        }  
        String data="haha";  
        response.getWriter().write(data);  
    }  
  
      
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
        doGet(request,response);  
    }  
  
}