can't read '%' for request.getparameter()

Question

Hi i have a hyperlink from hyperlink i am calling a servlet and also sending a parameter with request but when '%' appended with text then shows null value.

Code Of Jsp

 <h1><a href="test11?val=100%">click</a></h1>

Code of servlet

 String s=request.getParameter("val");
   out.print("this is a text"+s);

for <h1><a href="test11?val=100">click</a></h1> it works fine but when i add '%' it print null.

% is a special character in URLs. You have to encode it – Joshua Jun 19 '14 at 19:48 — Joshua, Jun 19 '14 at 19:48
Have you tried URL-encoding the `%`? – Abrixas2 Jun 19 '14 at 19:48 — Abrixas2, Jun 19 '14 at 19:48

score 5 · Accepted Answer · edited May 23 '17 at 10:31

5

In order to get the % from an URL you should use it's URLEncoded version which is %25. So you will end with <h1><a href="test11?val=100%25">click</a></h1>

% in an URL is not just a character, is the the main character for the percent-encoding used in URLEncoding. Other special characters for URLs are ?, & and =

Please try to always encode your URLs, in java please check this link:Java URL encoding of query string parameters in order to do so.

edited May 23 '17 at 10:31

Community

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answered Jun 19 '14 at 19:48

Garis M Suero

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How to do it? Please specify. – Braj Jun 19 '14 at 19:50
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replace '%' with '%25' – aProperFox Jun 19 '14 at 19:53
Your link shows how to do that in Java code, not in JSP. – Luiggi Mendoza Jun 19 '14 at 19:53
just add %25 before the number it will treat it as %. So i would append %25 in my string.Thank you Garis – user3660263 Jun 19 '14 at 19:54
Note: if you post to do this using scriptlet, your answer would become awful. – Luiggi Mendoza Jun 19 '14 at 19:54

Braj · Answer 2 · 2014-06-19T20:03:30.787

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Since you are using JSP then try with JSTL to encode the URL.

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<c:url value="/test11" var="url">
    <c:param name="val" value="100%" />
</c:url>

<a href="${url }">click</a>

Read more about JSP Standard Tag Library

edited Jun 19 '14 at 20:03

answered Jun 19 '14 at 19:55

Braj

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Note: we're at Java EE 7. Don't post links that belong to stone ages :). – Luiggi Mendoza Jun 19 '14 at 19:58
Thank you @Braj That really helped me out. learn a new thing about JSTL – user3660263 Jun 19 '14 at 20:03

can't read '%' for request.getparameter()

2 Answers2