1、application对象的常用方法：
<table>
<tr>
<%-- 获取当前Web服务器的版本信息--%>
<td>getServerInfo</td>
<td><%=application.getServerInfo()%></td>
</tr>
<tr>
<%-- 获取某一资源的路径--%>
<td>getResource</td>
<td><%=application.getResource("/application_test.jsp")%></td>
</tr>
<tr>
<%-- 获取根目录的路径--%>
<td>getRealPath</td>
<td><%=application.getRealPath("/")%></td>
</tr>
<tr>
<%-- 获取当前Web应用程序的名称--%>
<td>getServletContextName</td>
<td><%=application.getServletContextName()%></td>
</tr>
</table>
2、application、request、pageContext、session对象的作用域
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2019/9/26
Time: 19:48
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>各对象的作用域</title>
</head>
<body>
<%
if (application.getAttribute("accessCount") == null) {
application.setAttribute("accessCount", new Integer(1));
} else {
Integer accessCount = (Integer)application.getAttribute("accessCount");
accessCount += 1;
application.setAttribute("accessCount", accessCount);
}
%>
<%
if (request.getAttribute("accessCount") == null) {
request.setAttribute("accessCount", new Integer(1));
} else {
Integer accessCount = (Integer)request.getAttribute("accessCount");
accessCount += 1;
request.setAttribute("accessCount", accessCount);
}
%>
<%
if (pageContext.getAttribute("accessCount") == null) {
pageContext.setAttribute("accessCount", new Integer(1));
} else {
Integer accessCount = (Integer)pageContext.getAttribute("accessCount");
accessCount += 1;
pageContext.setAttribute("accessCount", accessCount);
}
%>
<%
if (session.getAttribute("accessCount") == null) {
session.setAttribute("accessCount", new Integer(1));
} else {
Integer accessCount = (Integer)session.getAttribute("accessCount");
accessCount += 1;
session.setAttribute("accessCount", accessCount);
}
%>
<%--application对象的作用域：开始于服务器的启动，终止于服务器的关闭--%>
application: <%=application.getAttribute("accessCount")%><br />
<%--request对象的作用域：该页面和从该页面转向的页面--%>
request: <%=request.getAttribute("accessCount")%><br />
<%--pageContext对象的作用域：该页面--%>
pageContext: <%=pageContext.getAttribute("accessCount")%><br />
<%--session对象的作用域：浏览器第一次向服务器发送请求到存储时间结束或显式调用invalidate方法--%>
session: <%=session.getAttribute("accessCount")%><br />
<%--<%request.getRequestDispatcher("index.jsp").forward(request,response);%>--%>
</body>
</html>
index.jsp ：
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2019/9/26
Time: 19:31
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>index.jsp页面</title>
</head>
<body>
<%
if (request.getAttribute("accessCount") == null) {
request.setAttribute("accessCount", new Integer(1));
} else {
Integer accessCount = (Integer)request.getAttribute("accessCount");
accessCount += 1;
request.setAttribute("accessCount", accessCount);
}
%>
<%=request.getAttribute("accessCount")%>
</body>
</html>
参考文档：
1）https://www.cnblogs.com/mark5/p/11075493.html
2）https://wenku.baidu.com/view/d98cea41336c1eb91b375d07.html
3）https://www.e-learn.cn/content/qita/2362810
4）https://www.cnblogs.com/chao521/p/9189484.html
原文地址：https://www.cnblogs.com/GjqDream/p/11594217.html
时间： 2024-12-11 17:25:52