Encode String to UTF-8

java

encoding

utf-8

string-manipulation

byNikita Barsukov·Nov 25, 2024

To encode a string to UTF-8 in Java you can use:

byte[] utf8Bytes = "yourString".getBytes(StandardCharsets.UTF_8);

This method does not require exceptions to be caught as StandardCharsets.UTF_8 ensures compatibility and allows for easy application.

Another convenient method to get an encoded string from a byte array in UTF-8 is:

String encodedString = new String(utf8Bytes, StandardCharsets.UTF_8);

Remember that the native encoding for String objects in Java is UTF-16. So, while dealing with special characters or multilingual text, encoding needs to be performed conscientiously to avoid any potential data corruption.

Handling special characters

UTF-8 and multilingual details

UTF-8 enables you to manage characters of diverse languages precisely. Understanding multi-byte characters is crucial, every byte is important:

// Maybe it's not about the money, but it is about the bytes...
byte[] euroSignBytes = "€".getBytes(StandardCharsets.UTF_8);  // [0xE2, 0x82, 0xAC]

ByteBuffer application

For more complex string manipulations or any related I/O operations, ByteBuffer provides a sturdier solution:

// Encodes the string and gives you a direct byte buffer, like pizza delivery but for bytes...
ByteBuffer buffer = StandardCharsets.UTF_8.encode("yourString");

Line up your charset

Before using methods like reflection on String objects, it might be worth confirming character set compatibility:

// Let's see if your string has a VIP pass for the ISO-8859-1 club
boolean isInCharsetRange = Charset.forName("ISO-8859-1").newEncoder().canEncode("yourString");

UTF-8 encoding strategies

Confirming UTF-8 encoding

An easy way to verify that a string is correctly encoded in UTF-8 is to compare byte arrays:

boolean isUtf8Encoded = Arrays.equals(utf8Bytes, "yourString".getBytes(StandardCharsets.UTF_8));

The care and handling of getBytes()

Make sure to always specify the charset when using String.getBytes():

byte[] defaultCharsetBytes = "yourString".getBytes(); // This method doesn't ask for directions...

A more advisable approach is to definitively state the encoding:

byte[] correctUtf8Bytes = "yourString".getBytes(StandardCharsets.UTF_8); // No confusion here, please!

Digging deeper with reflection

If need be, you can leverage reflection to inspect the internal encoding of a String object. This is rather advanced, so be careful not to get lost in the mirror!

explain-codes / Java / Encode String to UTF-8

Linked

Utf-8 byte[] to String



How to convert Strings to and from UTF8 byte arrays in Java



Get an OutputStream into a String



Encoding as Base64 in Java



How do I convert a String to an InputStream in Java?

