Question

我开发了simeple web应用程序。在一个jsp中，我使用getattribute和set属性从preivous servlet文件中获取值。我得到了值。但是现在我想从当前的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null。

firstjsp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：

            <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>

Answer 1

在HTML隐藏控件中设置您要在payment.jsp中访问的任何值，如下所示： -

<form action="payment.jsp" method="POST">
    <input type="hidden" name="amt" value="<%= amount%>" />
</form>

JSP中的请求对象仅跨越一个HTTP请求。因此，当您将请求转发到第一个JSP文件时，它只是一个请求。但是当您提交表单并加载payment.jsp时，请求对象将被清除，因为它是对服务器的新HTTP请求。

Answer 2

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：

<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>

Answer 3

为了访问您在第一个jsp中设置的值，最好以这种方式使用session来放置值。request.getSeession.setAttribute("amount",amount); 然后在第二个jsp访问它就像这样

<form>
 <input type="hidden" value="<%=session.getAttribute("amount")%>"/>
 <form>

我希望它能解决你的问题

从一个jsp到另一个jsp获取价值

3 个答案: