894@Where to get "UTF-8" string literal in Java?

Question

I'm trying to use a constant instead of a string literal in this piece of code:

new InputStreamReader(new FileInputStream(file), "UTF-8")

"UTF-8" appears in the code rather often, and would be much better to refer to some static final variable instead. Do you know where I can find such a variable in JDK?

Note: if you are already on Java 7, use Files.newBufferedWriter(Path path, Charset cs) from NIO. — Franklin Yu
– Franklin Yu, Commented Aug 8, 2018 at 14:55
That's some really bad advice from your link. He wants you to make a wrapper class for every possible string constant you might use? — Ariel
– Ariel, Commented Jun 25, 2020 at 20:15

Matthias Braun · Accepted Answer · 2025-05-26 00:00:52Z

1003

In Java 1.7+, the class java.nio.charset.StandardCharsets defines constants for Charset including UTF_8.

import java.nio.charset.StandardCharsets;

...

StandardCharsets.UTF_8.name();

For Android: minSdk 19

edited May 26 at 0:00

Matthias Braun

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answered Apr 17, 2013 at 18:01

Roger

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8 Comments

Matt Broekhuis Over a year ago

do you use .toString() on that?

Roger Over a year ago

.toString() will work but the proper function is .name(). 99.9% toString is not the answer.

Roger Over a year ago

btw .displayName() will also work unless it is overridden for localization as intended.

Natix Over a year ago

You don't really need to call name() at all. You can directly pass the Charset object into the InputStreamReader constructor.

Magnilex Over a year ago

And there are other libs out there which do require a String, perhaps because of legacy reasons. In such cases, I keep a Charset object around, typically derived from StandardCharsets, and use name() if needed.

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yegor256 · Accepted Answer · 2014-05-31 12:03:22Z

149

Now I use org.apache.commons.lang3.CharEncoding.UTF_8 constant from commons-lang.

edited May 31, 2014 at 12:03

answered Apr 26, 2012 at 8:04

yegor256

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4 Comments

Russell Silva Over a year ago

For those using Lang 3.0: org.apache.commons.lang3.CharEncoding.UTF_8. (Note "lang3").

Drew Stephens Over a year ago

If you're using Java 1.7, see @Roger's answer below since it's part of the standard library.

Gary Sheppard Over a year ago

P.S. "@Roger's answer below" is now @Roger's answer above. ☝

sendon1982 Over a year ago

That class is deprecated since Java 7 introduce java.nio.charset.StandardCharsets

Juan Moreno · Accepted Answer · 2017-01-09 19:46:57Z

73

The Google Guava library (which I'd highly recommend anyway, if you're doing work in Java) has a Charsets class with static fields like Charsets.UTF_8, Charsets.UTF_16, etc.

Since Java 7 you should just use java.nio.charset.StandardCharsets instead for comparable constants.

Note that these constants aren't strings, they're actual Charset instances. All standard APIs that take a charset name also have an overload that take a Charset object which you should use instead.

edited Jan 9, 2017 at 19:46

Juan Moreno

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answered Jul 14, 2011 at 18:52

Daniel Pryden

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8 Comments

AlikElzin-kilaka Over a year ago

So, should be Charsets.UTF_8.name()?

RKumsher Over a year ago

@kilaka Yeah use name() instead of getDisplayName() since name() is final and getDisplayName() is not

Daniel Pryden Over a year ago

@Buffalo: Please read my answer again: it recommends using java.nio.charset.StandardCharsets when possible, which is not third party code. Additionally, the Guava Charsets definitions are not "constantly modified" and AFAIK have never broken backwards compatibility, so I don't think your criticism is warranted.

Daniel Pryden Over a year ago

@Buffalo: That's as it may be, but I doubt your issues had anything to do with the Charsets class. If you want to complain about Guava, that's fine, but this is not the place for those complaints.

Jeffrey Blattman Over a year ago

Please do not include a multi-megabyte library to get one string constant.

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cosjav · Accepted Answer · 2013-04-17 04:56:49Z

51

In case this page comes up in someones web search, as of Java 1.7 you can now use java.nio.charset.StandardCharsets to get access to constant definitions of standard charsets.

answered Apr 17, 2013 at 4:56

cosjav

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4 Comments

Roger Over a year ago

I have been trying to use this but it does not seem to work. 'Charset.defaultCharset());' seems to work after including 'java.nio.charset.*' but I can't seem to explicitly refer to UTF8 when I am trying to use 'File.readAllLines'.

cosjav Over a year ago

@Roger What seems to be the problem? From what I can see you can just call: Files.readAllLines(Paths.get("path-to-some-file"), StandardCharsets.UTF_8);

Roger Over a year ago

I don't know what the problem was, but it worked for me after changing something which I can't remember.

Bitbang3r Over a year ago

^^^ You probably had to change the target platform in the IDE. If 1.6 was your latest JDK when you installed the IDE, it probably picked it as the default & kept it as the default long after you'd updated both the IDE and JDK themselves in-place.

Alfredo Carrillo · Accepted Answer · 2013-01-10 22:33:21Z

10

This constant is available (among others as: UTF-16, US-ASCII, etc.) in the class org.apache.commons.codec.CharEncoding as well.

answered Jan 10, 2013 at 22:33

Alfredo Carrillo

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Comments

Mostafa Vatanpour · Accepted Answer · 2018-07-23 15:46:55Z

10

In Java 1.7+

Do not use "UTF-8" string, instead use Charset type parameter:

import java.nio.charset.StandardCharsets

...

new InputStreamReader(new FileInputStream(file), StandardCharsets.UTF_8);

answered Jul 23, 2018 at 15:46

Mostafa Vatanpour

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Comments

tskuzzy · Accepted Answer · 2011-07-14 18:51:11Z

9

There are none (at least in the standard Java library). Character sets vary from platform to platform so there isn't a standard list of them in Java.

There are some 3rd party libraries which contain these constants though. One of these is Guava (Google core libraries): http://guava-libraries.googlecode.com/svn/trunk/javadoc/com/google/common/base/Charsets.html

answered Jul 14, 2011 at 18:51

tskuzzy

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3 Comments

Ed Staub Over a year ago

It took me a second to catch on to this... Guava's Charsets constants are (no surprise) Charsets, not Strings. InputStreamReader has another constructor that takes a Charset rather than a string. If you really need the string, it's e.g. Charsets.UTF_8.name().

tar Over a year ago

Character sets do may vary from platform to platform, but UTF-8 is guaranteed to exist.

Krzysztof Krasoń Over a year ago

All charsets defined in StandardCharsets are guaranteed to exist in every Java implementation on every platform.

Andrew · Accepted Answer · 2016-10-17 21:45:09Z

8

You can use Charset.defaultCharset() API or file.encoding property.

But if you want your own constant, you'll need to define it yourself.

edited Oct 17, 2016 at 21:45

Andrew

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answered Jul 14, 2011 at 18:49

paulsm4

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1 Comment

Jörn Horstmann Over a year ago

The default charset is usually determinded by the OS and locale settings, I don't think there is any guarantee that it remains the same for multiple java invocations. So this is no replacement for a constant sepcifying "utf-8".

JJD · Accepted Answer · 2015-10-07 08:58:20Z

5

If you are using OkHttp for Java/Android you can use the following constant:

import com.squareup.okhttp.internal.Util;

Util.UTF_8; // Charset
Util.UTF_8.name(); // String

answered Oct 7, 2015 at 8:58

JJD

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1 Comment

mtrakal Over a year ago

it's removed from OkHttp, so next way is: Charset.forName("UTF-8").name() when you need support for lower Android than API 19+ otherwise you can use: StandardCharsets.UTF_8.name()

Vazgen Torosyan · Accepted Answer · 2018-03-26 10:34:32Z

5

Constant definitions for the standard. These charsets are guaranteed to be available on every implementation of the Java platform. since 1.7

 package java.nio.charset;
 Charset utf8 = StandardCharsets.UTF_8;

answered Mar 26, 2018 at 10:34

Vazgen Torosyan

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sendon1982 · Accepted Answer · 2020-05-11 03:45:00Z

4

Class org.apache.commons.lang3.CharEncoding.UTF_8 is deprecated after Java 7 introduced java.nio.charset.StandardCharsets

@see JRE character encoding names
@since 2.1
@deprecated Java 7 introduced {@link java.nio.charset.StandardCharsets}, which defines these constants as
{@link Charset} objects. Use {@link Charset#name()} to get the string values provided in this class.
This class will be removed in a future release.

answered May 11, 2020 at 3:45

sendon1982

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