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javastringasciiarrays

How to convert a Java String to an ASCII byte array?

How to convert a Java String to an ASCII byte array?

Solution

  • Using the getBytes method, giving it the appropriate Charset (or Charset name).

    Example:

    String s = "Hello, there.";
byte[] b = s.getBytes(StandardCharsets.US_ASCII);

    If more control is required (such as throwing an exception when a character outside the 7 bit US-ASCII is encountered) then CharsetDecoder can be used:

    private static byte[] strictStringToBytes(String s, Charset charset) throws CharacterCodingException {
    ByteBuffer x  = charset.newEncoder().onMalformedInput(CodingErrorAction.REPORT).encode(CharBuffer.wrap(s));
    byte[] b = new byte[x.remaining()];
    x.get(b);
    return b;
 }

    Before Java 7 it is possible to use: byte[] b = s.getBytes("US-ASCII");. The enum StandardCharsets, the encoder as well as the specialized getBytes(Charset) methods have been introduced in Java 7.