先看看实现后的效果：
count.jsp
点击后跳转到show.jsp
点击返回再次点击test后
count.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>count</title>
</head>
<body>
<form action="ServletCount" method="post">
<input type="submit" value="test">
</form>
</body>
</html>在web.xml中设置一个计数器对象
<welcome-file-list>
<welcome-file>counter</welcome-file>
</welcome-file-list>ServletCount
获取计数器对象并实现调用时加一操作，
并将次数发送到show.jsp中
package servlet;
import java.io.IOException;
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;
/**
* Servlet implementation class ServletCount
*/
@WebServlet("/ServletCount")
public class ServletCount extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public ServletCount() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
ServletContext context = getServletContext(); // 从ServletContext中获取计数器对象
Integer count = (Integer) context.getAttribute("counter");
if(count == null)
{// 如果为空，则在ServletContext中设置一个计数器的属性
count = 1;
context.setAttribute("counter", count);
}
else
{
count++;
context.setAttribute("counter", count);
}
request.setAttribute("count", count);
request.getRequestDispatcher("show.jsp").forward(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
show.jsp
显示结果
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>show</title>
</head>
<body>
<h2>
<%
int count = (Integer) request.getAttribute("count");
%>
<h2>
访问量:[<%=count%>]
</h2>
<button onclick="window.location.href='count.jsp'">返回</button>
</body>
</html>
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