Servlet-一种防盗链

package com.pas.web;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class RequestTest extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setContentType("text/html");
		response.setCharacterEncoding("gb2312");
		PrintWriter out = response.getWriter();
		//通过request获取HTTP请求
		String ref=request.getHeader("Referer");
		if(null==ref||!ref.startsWith("http://localhost:8080/HelloServlet/"))
		{
			response.sendRedirect("/err.html");
			out.println(ref);
			return;
		}


	}

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

		this.doGet(request, response);
	}

}