Encode String to UTF-8

Question

How about using

ByteBuffer byteBuffer = StandardCharsets.UTF_8.encode(myString)

String objects in Java use the UTF-16 encoding that can't be modified.

The only thing that can have a different encoding is a byte[]. So if you need UTF-8 data, then you need a byte[]. If you have a String that contains unexpected data, then the problem is at some earlier place that incorrectly converted some binary data to a String (i.e. it was using the wrong encoding).

In Java7 you can use:

import static java.nio.charset.StandardCharsets.*;

byte[] ptext = myString.getBytes(ISO_8859_1); 
String value = new String(ptext, UTF_8); 

This has the advantage over getBytes(String) that it does not declare throws UnsupportedEncodingException.

If you're using an older Java version you can declare the charset constants yourself:

import java.nio.charset.Charset;

public class StandardCharsets {
    public static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
    public static final Charset UTF_8 = Charset.forName("UTF-8");
    //....
}

Use byte[] ptext = String.getBytes("UTF-8"); instead of getBytes(). getBytes() uses so-called "default encoding", which may not be UTF-8.

A Java String is internally always encoded in UTF-16 - but you really should think about it like this: an encoding is a way to translate between Strings and bytes.

So if you have an encoding problem, by the time you have String, it's too late to fix. You need to fix the place where you create that String from a file, DB or network connection.