不要使用 JSP 重置公式字段中的输入

发布于 2024-10-03 12:08:36 字数 1717 浏览 0 评论 0原文

我正在练习 JSP，并且想要创建一个简单的公式字段。下面的代码工作正常。现在我希望最后的输入保留在公式字段中。因此，当我输入值“密码”和“名称”时，无论 if-else 语句的结果是什么，这两个值都应保留在公式字段中。

例如，我输入“用户”和“1234”并按提交，公式字段被清除，我不希望这样。提交后这两个值将保留在那里。真诚地，我不知道如何解决这个问题。

我的建议是使用 application.setAttribute("",) 和 application.getAttribute("")，但我不知道如何。我很乐意提供任何建议。谢谢你！

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
          "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="de">

<head>
  <title>Practice</title>
</head>

<body>

<h2>Practice</h2>
<h3>Please enter your name and the password.</h3>
<form method="post" action="">
  <table>
<tr><td style="text-align:center">Name</td>
<td><input type="text" name="name" size="80" /></td>
</tr>
<tr><td style="text-align:center">Password</td>
<td><input type="text" name="password" size="80" /></td>
</tr>
<tr><td><input type="submit" value="Send" /></td>
<td><input type="reset" value="Reset" /></td>
</tr>
</table>
</form>

<%-- Testing name and password. --%>
<% String name = request.getParameter("name");
   String password = request.getParameter("password");
   if (name != null && name.equals("user") && password != null && password.equals("1234"))
     {
%>
       <p>Your Input is correct!</p>
<%   }

   else
     {
%>
       <p>Your input is not correct!</p>
<%   }
%>

</body>


</html>

原文

I'm practising a bit on JSP and want to create a simple formular field. The code below is working properly. Now i want that the last input stays in the formular fields. So when i type in a value "password" and a "name" both values should stay in the formular field no matter what the result of the if-else statement is.

For example i type in "user" and "1234" and press submit the formular fields get cleared and i don't want that. The two values shall stay there after submitting. Sincerly i have no good idea how to solve this problem.

My suggestion would be to use application.setAttribute("",) and application.getAttribute(""), but i don't know how. I would be glad for any advise. Thank you!

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
          "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="de">

<head>
  <title>Practice</title>
</head>

<body>

<h2>Practice</h2>
<h3>Please enter your name and the password.</h3>
<form method="post" action="">
  <table>
<tr><td style="text-align:center">Name</td>
<td><input type="text" name="name" size="80" /></td>
</tr>
<tr><td style="text-align:center">Password</td>
<td><input type="text" name="password" size="80" /></td>
</tr>
<tr><td><input type="submit" value="Send" /></td>
<td><input type="reset" value="Reset" /></td>
</tr>
</table>
</form>

<%-- Testing name and password. --%>
<% String name = request.getParameter("name");
   String password = request.getParameter("password");
   if (name != null && name.equals("user") && password != null && password.equals("1234"))
     {
%>
       <p>Your Input is correct!</p>
<%   }

   else
     {
%>
       <p>Your input is not correct!</p>
<%   }
%>

</body>


</html>

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戏剧牡丹亭 2024-10-10 12:08:36

只需使用提交的值填充其 value 属性即可。在正常 JSP EL 中，这将是：

<%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn" %>
...
<input type="text" name="username" value="${fn:escapeXml(param.username)}" />
<input type="password" name="password" value="${fn:escapeXml(param.password)}" />

${param.username} 的作用与下面丑陋的 scriptlet 基本相同% if (request.getParameter("用户名") != null) { out.print(request.getParameter("用户名")); } %>，只是以一种更加干净和简洁的方式。

JSTL fn:escapeXml() 函数可以防止您XSS< /a> 攻击。否则，用户将能够输入 "> 作为名称并执行它（当然，使用更恶意的 javascript，它会发送例如，将 cookies 发送到另一台服务器，而不是简单的警报）。

Just fill their value attribute with the submitted value. In normal JSP EL that would be:

<%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn" %>
...
<input type="text" name="username" value="${fn:escapeXml(param.username)}" />
<input type="password" name="password" value="${fn:escapeXml(param.password)}" />

The ${param.username} does basically the same as the following ugly scriptlet <% if (request.getParameter("username") != null) { out.print(request.getParameter("username")); } %>, only in a much more clean and consice way.

The JSTL fn:escapeXml() function is there to prevent you from XSS attacks. Otherwise users would be able to enter "><script>alert('xss');</script> as name and get it executed (of course with a more malicious javascript which sends the cookies to another server for example instead of a simple alert).

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