java servlet: request parameter contains plus

Question

The request parameter is like decrypt?param=5FHjiSJ6NOTmi7/+2tnnkQ==.

In the servlet, when I try to print the parameter by String param = request.getParameter("param"); I get 5FHjiSJ6NOTmi7/ 2tnnkQ==. It turns the character + into a space. How can I keep the orginal paramter or how can I properly handle the character +.

Besides, what else characters should I handle?

score 6 · Accepted Answer · edited May 23 '17 at 12:17

You have two choices

URL encode the parameter

If you have control over the generation of the URL you should choose this. If not...

Manually retrieve the parameter

If you can't change how the URL is generated (above) then you can manually retrieve the raw URL. Certain methods decode parameters for you. getParameter is one of them. On the other hand, getQueryString does not decode the String. If you have only a few parameters it shouldn't be difficult to parse the value yourself.

request.getQueryString();
//?param=5FHjiSJ6NOTmi7/+2tnnkQ==

Mark Thomas · Answer 2 · 2013-10-10T21:54:46.790

2

If you want to use the '+' character in a URL you need to encode it when it is generated. For '+' the correct encoding is %2b

edited Oct 10 '13 at 21:54

answered Oct 10 '13 at 20:39

Mark Thomas

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Sorry got hung up on the space rather than the +. I'll fix my answer. – Mark Thomas Oct 10 '13 at 21:54

score 0 · Answer 3 · answered Oct 10 '13 at 18:10

0

Use URLEncoder,URLDecoder's static methods for encoding and decoding URLs.

For example : - Encode the URL param using

    URLEncoder.encode(url,"UTF-8")

Back in the server side , decode this parameter using

    URLDecoder.decode(url,"UTF-8")

decode method returns a String type of the decoded URL.

answered Oct 10 '13 at 18:10

NishM

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In servlets, there's never a need to URL-decode a `request.getParameter()`. The container does that all by itself. – BalusC Oct 10 '13 at 18:12
My bad. Thanks BalusC – NishM Mar 13 '17 at 22:15

score 0 · Answer 4 · answered Sep 23 '16 at 14:01

Allthough the question is some years old, I'd like to write down how I fixed the problem in my case: the download link to a file is created in a GWT page where

com.google.gwt.http.client.URL.encode(finalurl)

is used to encode the URL. The problem was that the "+" sign a customer of us had in the filename wasn't encoded/escaped. So I had to remove the URL.encode(finalurl) and encode each parameter in the url with

URL.encodePathSegment(fileName)

I know my question is bound to GWT but it seems, URLEncoder.encode(string, encoding) should be applied to the parameter only aswell.

java servlet: request parameter contains plus

4 Answers4

URL encode the parameter

Manually retrieve the parameter

Linked