初学JSP，求解答。

java初学者加入小组

294个成员 65个话题创建时间：2015-02-03

发表于2016-12-10 2480次查看

test1.jsp

<%@page contentType="text/html" pageEncoding="utf-8"
%><!DOCTYPE html>
<html lang="zh-CN">
<head>
	<meta charset="utf-8">
	<title>测试页</title>
</head>
<body>
<jsp:include page="test2.jsp"/>
<%=response.getHeader("refresh")%><br><br>
<%=request.getAttribute("info")%>
</body>
</html>

test2.jsp

<%@page contentType="text/html" pageEncoding="utf-8"
%>
<%
	response.setHeader("refresh","10;URL=test3.jsp");
	request.setAttribute("info","Hello World!!!");
%>

test3.jsp

<%@page contentType="text/html" pageEncoding="utf-8"
%><!DOCTYPE html>
<html lang="zh-CN">
<head>
	<meta charset="utf-8">
	<title>www.baidu.com</title>
</head>
<body>
<h1>百度一下，你就知道！</h1>
</body>
</html>

浏览器访问test1.jsp，结果如下，为什么是null？

-------------------------------------------------------------------------------

test4.jsp

<%@page contentType="text/html" pageEncoding="utf-8"
%>
<%
	response.setHeader("refresh","10;URL=test3.jsp");
%>
<jsp:forward page="test5.jsp"/>

test5.jsp

<%@page contentType="text/html" pageEncoding="utf-8"
%><!DOCTYPE html>
<html lang="zh-CN">
<head>
	<meta charset="utf-8">
	<title>测试页</title>
</head>
<body>
<span style="font-size:30px">test5</span><br><br>
<%=response.getHeader("refresh")%>
</body>
</html>

浏览器访问test4.jsp，服务器端跳转到test5.jsp，response能正常获取header，且10秒后能跳转到test3.jsp