统计网站访问量

package cn.ttt.Servlet;

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

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 统计访问量
 */
@WebServlet("/AServlet")
public class AServlet extends HttpServlet {
	
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		/*
		 * 1.获取ServletContext对象
		 * 2.从ServletContext对象中获取名为count的属性。
		 * 3.如果存在:给访问量加1，然后再保存回去;
		 * 4.如果不存在:说明是第一次访问，向ServletContext中保存名为count的属性，值为1。
		 */
		ServletContext application = this.getServletContext();
		Integer count = (Integer)application.getAttribute("count");
		if(count == null){
			application.setAttribute("count", 1);
		}else{
			application.setAttribute("count", count+1);
		}
		/*
		 * 向浏览器输出
		 * 需要使用响应对象
		 */
		PrintWriter pw = response.getWriter();
		pw.print("<h1>"+count+"</h1>");
		
		
	}

}