How to convert UTF-8 to unicode in Java?

Question

For example, in Emoji Char set, U+1F601 is the unicode value for "GRINNING FACE WITH SMILING EYES", and \xF0\x9F\x98\x81 is the UTF-8 bytes value for this character.

\xE2\x9D\xA4 is for heavy black heart, and the unicode is U+2764.

So my question is, if I have a byte array with value (0xF0, 0x9F, 0x98, 0x81, 0xE2, 0x9D, 0xA4), then how I can convert it into Unicode value?

For the above result, what I want is a String array with value "1F601" and "2764".

I know I can write a complex method to do this work, but I hope there is already a library to do this work.

Solution 1

So my question is, if I have a byte array with value (0xF0, 0x9F, 0x98, 0x81), then how I can convert it into Unicode value?

Simply call the String constructor specifying the data and the encoding:

String text = new String(bytes, "UTF-8");

You can specify a Charset instead of the name of the encoding - I like Guava's simple Charsets class, which allows you to write:

String text = new String(bytes, Charsets.UTF_8);

Or for Java 7, use StandardCharsets without even needing Guava:

String text = new String(bytes, StandardCharsets.UTF_8);

Solution 2

Simply use String class:

byte[] bytesArray = new byte[10]; // array of bytes (0xF0, 0x9F, 0x98, 0x81)

String string = new String(bytesArray, Charset.forName("UTF-8")); // covert byteArray

System.out.println(string); // Test result

Comments

[artbristol]

If you use Java 7's java.nio.charset.StandardCharsets you don't even need Guava

[Jon Skeet]

@artbristol: Thanks - I had a quick look, but missed that. Will edit it in.

[Ponni Radhakrishnan]

@JonSkeet please what's the equivalent in .net or c#

[Jon Skeet]

@CharlesO: You'd use Encoding.UTF8.GetBytes(text), and in reverse, Encoding.UTF8.GetString(bytes).

[Ponni Radhakrishnan]

@JonSkeet I seem to be looking for the wrong thing here... Yes i'm aware we can use the GetBytes and GetString this is what i was unclear about: stackoverflow.com/questions/26151972/…

[Jon Skeet]

@CharlesO: Okay - I was giving the .NET equivalent of the code in my question, which is what I thought you were after. So do you now have everything you need?

[Ponni Radhakrishnan]

@JonSkeet Not quite, please see the the question I linked to. above. thanks

[Jon Skeet]

@CharlesO: Ah, I thought you'd linked to a different question. Will look now.