Html 在 response.sendRedirect() 中传递参数 - JSP
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Passing parameters in a response.sendRedirect() - JSP
提问by Bernice
I am new to Web Technologies. I am trying to do a simple program which ask the user to input a name, if valid the page redirects to another jsp file "RedirectIfSuccessful.jsp", if invalid the page redirects to "RedirectIfFailed.jsp". I am using the response.sendRedirect()method to do this.
我是 Web 技术的新手。我正在尝试做一个简单的程序，它要求用户输入一个名称，如果有效页面重定向到另一个 jsp 文件"RedirectIfSuccessful.jsp"，如果无效页面重定向到.jsp 文件"RedirectIfFailed.jsp"。我正在使用该response.sendRedirect()方法来执行此操作。
The redirect is working fine. However, I wish to access the name the user inputs in the form from RedirectIfSuccessfuland RedirectIfFailedfiles so that when a valid name is entered the user is presented with a : Welcome, nameEntered and when failed the message would be nameEntered was not valid. Please go back and try again.
重定向工作正常。但是，我希望访问用户在表单RedirectIfSuccessful和RedirectIfFailed文件中输入的名称，以便在输入有效名称时向用户显示：Welcome, nameEntered，失败时消息将是 nameEntered is not valid。请返回重试。
I tried using request.getParameter("name")from both files but it's returning a nullvalue.. What can I do to access it?
我尝试request.getParameter("name")从这两个文件中使用，但它返回一个null值.. 我该怎么做才能访问它？
This is the code I have: This is the RedirectingPage.jsp
这是我的代码：这是 RedirectingPage.jsp
<%@ page
language="java"
import="java.util.regex.*"
contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%
String name = request.getParameter("name");
final String NAME_PATTERN = "^[a-zA-Z]{3,15}$";
Pattern pattern = Pattern.compile(NAME_PATTERN);
Matcher matcher = pattern.matcher(name);
if (matcher.matches() == true){
response.sendRedirect("RedirectIfSuccessful.jsp");
} else {
response.sendRedirect("RedirectIfFailed.jsp");
}
%>
This is the HTML file where I have the form: FormSubmit.html
这是我有表单的 HTML 文件： FormSubmit.html
<html>
<head>
<title> Welcome </title>
</head>
<body BGCOLOR="#FDF5E6">
<p> <i> This program redirects to a page if the name entered is valid and to another one if name
entered is invalid... This uses response.sendRedirect() </i> </p>
<form action="RedirectingPage.jsp" method="post">
<font size=6 face="Georgia"> <strong> Enter your name: </strong> </font> <input type="text" name="name"> <br> <br>
<input type="submit" name="btn" value="Submit" >
</form>
</body>
</html>
And this is the Successful page:
这是成功页面：
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title> Successful Submit </title>
</head>
<body>
<font face="Georgia" size="6"> Hello, <% request.getParameter("name"); %> </font>
</body>
</html>
I hope you can help and I was clear in my question. Thanks :)
我希望你能帮忙，我的问题很清楚。谢谢 ：）
回答by JB Nizet
A redirect consists in sending a response to the browser saying "Please go to the following URL : RedirectIfSuccessful.jsp".
重定向包括向浏览器发送响应，说“请转到以下 URL：RedirectIfSuccessful.jsp”。
When it receives this response, the browser sends a new request to RedirectIfSuccessful.jsp, without any parameter. So getting the parameter namefrom RedirectIfSuccessful.jspwill return null.
当它收到这个响应时，浏览器向 发送一个新请求RedirectIfSuccessful.jsp，不带任何参数。所以获取参数namefromRedirectIfSuccessful.jsp将返回 null。
If you want to have access to the name after the redirection, you need to send a redirect to RedirectIfSuccessful.jsp?name=<the name the user entered>
如果您想在重定向后访问名称，则需要发送重定向到 RedirectIfSuccessful.jsp?name=<the name the user entered>
回答by HILLARY RONOH-MMUST
To get the name in another page, use session.
要在另一个页面中获取名称，请使用 session。
e.g. session.setAttribute("name",name)at the login page;
例如session.setAttribute("name",name)在登录页面；
To retrieve the name, use session.getAttribute("name"). You can assign it to a variable like this:
要检索名称，请使用session.getAttribute("name"). 您可以将其分配给这样的变量：
<% String name=(string)session.getAttribute("name");%>
success!
成功！
