使用Session实现访问计数

package test;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;import javax.servlet.http.HttpSession;/** * 使用Session实现访问计数 */public class CountServlet extends HttpServlet {@Overrideprotected void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {HttpSession session = req.getSession();Integer count = (Integer)session.getAttribute("count");if(count == null){//第一次访问count = 1;}else{count++;}session.setAttribute("count", count);res.setContentType("text/html;charset=utf-8");PrintWriter out  = res.getWriter();out.println("登录次数:"+count);out.close();}}