在response.sendRedirect()中传递参数-JSP [英] Passing parameters in a response.sendRedirect() - JSP
问题描述
我是Web技术的新手.我正在尝试做一个简单的程序，要求用户输入名称，如果有效，页面将重定向到另一个jsp文件"RedirectIfSuccessful.jsp"，如果无效，则页面将重定向到"RedirectIfFailed.jsp".我正在使用response.sendRedirect()方法来做到这一点.
重定向正常.但是，我希望访问用户以RedirectIfSuccessful和RedirectIfFailed文件的形式输入的名称，以便在输入有效名称时向用户显示:欢迎，nameEntered，失败时将显示nameEntered消息.无效.请返回，然后重试.
我尝试从两个文件中使用request.getParameter("name")，但是它返回一个null值.我该怎么办?
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");
}
%>
这是我具有以下格式的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>
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>
希望您能提供帮助，我的问题很明确.谢谢:)
重定向是向浏览器发送一条响应，内容为请转到以下URL:RedirectIfSuccessful.jsp" .
当收到此响应时，浏览器将不带任何参数的新请求发送到RedirectIfSuccessful.jsp.因此，从RedirectIfSuccessful.jsp获取参数name将返回null.
如果您希望在重定向后能够访问该名称，则需要将重定向发送到RedirectIfSuccessful.jsp?name=<the name the user entered>
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.
The redirect is working fine. However, I wish to access the name the user inputs in the form from RedirectIfSuccessful and RedirectIfFailed files 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.
I tried using request.getParameter("name") from both files but it's returning a null value.. What can I do to access it?
This is the code I have: This is the 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
<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:
<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 :)
A redirect consists in sending a response to the browser saying "Please go to the following URL : RedirectIfSuccessful.jsp".
When it receives this response, the browser sends a new request to RedirectIfSuccessful.jsp, without any parameter. So getting the parameter name from RedirectIfSuccessful.jsp will return 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>
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