java 从一个jsp到另一个jsp获取价值
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Getting value from one jsp to another jsp
提问by VijayKumar
I developed simeple web application. In one jsp i get values from preivous servlet file using getattribute and set attribute.I got the values. But after now i want that values from current jsp to another jsp file. Using getattribute and setattribute i used but the values should display as null.
我开发了简单的网络应用程序。在一个jsp中，我使用getattribute和set attribute从以前的servlet文件中获取值。我得到了这些值。但是现在我想要从当前jsp到另一个jsp文件的值。使用我使用的 getattribute 和 setattribute，但值应显示为空。
firstjsp file:
第一个jsp文件：
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@ page import="javax.servlet.http.*" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<form action="payment.jsp" method="POST">
<h1>Confirmation</h1>
<%
Integer amount=(Integer)request.getAttribute("amt");
String service=(String )request.getAttribute("service");
String month=(String )request.getAttribute("month");
Integer day=(Integer)request.getAttribute("day");
String time=(String)request.getAttribute("time");
String city=(String)request.getAttribute("city");
out.println("<center>");
out.println("<table><tr>");
out.println("<td><h2>Service:"+service+"</td></tr>");
out.println("<tr><td><h2>Month:"+month+"</td></tr>");
out.println("<tr><td><h2>Date:"+day+"</td></tr>");
out.println("<tr><td><h2>Time:"+time+"</td></tr>");
out.println("<tr><td><h2>City:"+city+"</td></tr>");
out.println("<tr><td><h2>Total Amount:Rs."+amount+"</td></tr>");
out.println("</center>");
request.setAttribute("amt",amount);
%>
<center>
<input type="submit" value="Confirm"></input>
</center>
</form>
</body>
</html>
payment.jsp:
付款.jsp：
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<h2>Select bank</h2>
<%!Integer money;%>
<%
if(request.getAttribute("amt")!=null)
{
money=(Integer) request.getAttribute("amt");
out.println(""+money);
}
%>
</body>
</html>
回答by verisimilitude
Set whatever values you want to access in payment.jspin HTML hidden control as below :-
payment.jsp在 HTML 隐藏控件中设置要访问的任何值，如下所示：-
<form action="payment.jsp" method="POST">
<input type="hidden" name="amt" value="<%= amount%>" />
</form>
Request object in JSP spans only a single HTTP request. So when you forward the request to your first JSP file it is a single request. But when you submit the form and payment.jsploads, the request object is cleared since it is a new HTTP request to the server.
JSP 中的请求对象仅跨越单个 HTTP 请求。因此，当您将请求转发到您的第一个 JSP 文件时，它是一个单一的请求。但是当您提交表单并payment.jsp加载时，请求对象将被清除，因为它是对服务器的新 HTTP 请求。
回答by Visruth
You may use sessioninstead of requestimplicit object.
您可以使用session代替request隐式对象。
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<form action="payment.jsp" method="POST">
<h1>Confirmation</h1>
<%
Integer amount=(Integer)request.getAttribute("amt");
String service=(String )request.getAttribute("service");
String month=(String )request.getAttribute("month");
Integer day=(Integer)request.getAttribute("day");
String time=(String)request.getAttribute("time");
String city=(String)request.getAttribute("city");
out.println("<center>");
out.println("<table><tr>");
out.println("<td><h2>Service:"+service+"</td></tr>");
out.println("<tr><td><h2>Month:"+month+"</td></tr>");
out.println("<tr><td><h2>Date:"+day+"</td></tr>");
out.println("<tr><td><h2>Time:"+time+"</td></tr>");
out.println("<tr><td><h2>City:"+city+"</td></tr>");
out.println("<tr><td><h2>Total Amount:Rs."+amount+"</td></tr>");
out.println("</center>");
session.setAttribute("amt",amount);//Changed to session
%>
<center>
<input type="submit" value="Confirm"></input>
</center>
</form>
</body>
</html>
payment.jsp:
付款.jsp：
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<h2>Select bank</h2>
<%!Integer money;%>
<%
if(session.getAttribute("amt")!=null)//changed to session
{
money=(Integer) session.getAttribute("amt");//changed to session
out.println(""+money);
session.removeAttribute("amt");
}
%>
</body>
</html>
回答by Birhan Nega
in order to access the value you set in the first jsp, you have better to put the value using session in this way.request.getSeession.setAttribute("amount",amount);then in the second jsp access it like this
为了访问您在第一个jsp中设置的值，您最好以这种方式使用session来放置该值。request.getSeession.setAttribute("amount",amount);然后在第二个jsp中像这样访问它
<form>
<input type="hidden" value="<%=session.getAttribute("amount")%>"/>
<form>
i hope it solves your problem
我希望它能解决你的问题
