src/com/itbaizhan/servlet/SessAdminServlet.java

微信扫码关注公众号，代码整理好后第一时间通知你。

package com.itbaizhan.servlet;

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 SessAdminServlet extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public SessAdminServlet() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		PrintWriter pw = response.getWriter();
		if(request.getSession().getAttribute("adminlogin") == null || request.getSession().getAttribute("adminlogin").equals("")){
			pw.write("<script>alert('您还没有登录!');window.navigate('index.jsp');</script>");
		}
	}

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

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occure
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}