Question

Is there any function in Java that converts a string to a byte array?

Answer 1

Yes: String.getBytes. You really, really want to specify the character encoding when you do so though – using the platform default encoding is almost always the wrong thing to do.

Ideally, it’s best to specify the encoding via a Charset – that way you don’t need to worry about the UnsupportedEncodingException which can be thrown by the overload of getBytes which just takes a String with the character encoding name as an argument.

EDIT: Based on your comment, it looks like you want to parse a hex string into a byte array. (It would have been useful to say so in your question.) String.getBytes is inappropriate for this – I don’t believe there’s anything which does this in the standard libraries, but the Apache Commons Codec library makes it pretty easy:

byte[] data = Hex.decodeHex(text.toCharArray());