How to percent encode in Java?

Question

How do I do percent encoding of a string, as described in RFC 3986? I.e. I do not want (IMO, weird) www-url-form-encoded, as that is different.

If it matters, I am encoding data that is not necessarily an entire URL.

This do it for you?https://docs.oracle.com/javase/7/docs/api/java/net/URLEncoder.html. Woops, didnt read properly. Ignore — Zack Newsham, Dec 01 '14 at 01:00
Could you define "standard"? Does it have to encode spaces in the URL as `%20`, and spaces in the query string as `+`? What about other special characters? — tckmn, Dec 01 '14 at 01:01
ok, here you go: http://stackoverflow.com/questions/4737841/urlencoder-not-able-to-translate-space-character — Zack Newsham, Dec 01 '14 at 01:01
Does Guava's [`PercentEscaper`](http://docs.guava-libraries.googlecode.com/git-history/release/javadoc/com/google/common/net/PercentEscaper.html) work for you? Or, rather, one of [the URL escapers](http://docs.guava-libraries.googlecode.com/git-history/release/javadoc/com/google/common/net/UrlEscapers.html)? — Petr Janeček, Dec 01 '14 at 01:03
Does this answer your question? [Java URL encoding of query string parameters](https://stackoverflow.com/questions/10786042/java-url-encoding-of-query-string-parameters) — fireball.1, Apr 21 '21 at 18:10

Petr Janeček · Answer 1 · 2017-12-29T22:39:37.297

7

As you have identified, the standard libraries don't cope very well with the problem.

Try to use either Guava's PercentEscaper, or directly one of the URL escapers depending on which part of the URL you're trying to encode.

edited Dec 29 '17 at 22:39

answered Dec 01 '14 at 01:09

Petr Janeček

The links are broken. – Slava Semushin Dec 29 '17 at 21:24
Guava's com.google.common.net.PercentEscaper is marked "Beta" and therefore unstable – electrobabe Mar 15 '20 at 02:19
(Links fixed, and PercentEscaper is no longer beta since Guava 31.1. Even if you have to use an older Guava, only refrain from using @Beta APIs if you're creating a library. In an application they're fine.) – Petr Janeček Sep 12 '22 at 09:44

score 6 · Answer 2 · answered Mar 15 '20 at 02:37

Guava's com.google.common.net.PercentEscaper (marked "Beta" and therefore unstable):

UnicodeEscaper basicEscaper = new PercentEscaper("-", false);
String s = basicEscaper.escape(s);

Workaround with java.net.URLEncoder:

try {
  String s = URLEncoder.encode(s, "UTF-8").replace("+", "%20");
} catch (UnsupportedEncodingException e) {
  ..
}

2 Answers2