Calculating length in UTF-8 of Java String without actually encoding it

Question

Does anyone know if the standard Java library (any version) provides a means of calculating the length of the binary encoding of a string (specifically UTF-8 in this case) w

Answer 1

You can loop thru the String:

/**
 * Deprecated: doesn't support surrogate characters.
 */
@Deprecated
public int countUTF8Length(String str)
{
    int count = 0;
    for (int i = 0; i < str.length(); ++i)
    {
        char c = str.charAt(i);
        if (c < 0x80)
        {
            count++;
        } else if (c < 0x800)
        {
            count +=2;
        } else
            throw new UnsupportedOperationException("not implemented yet");
        }
    }
    return count;
}