is there any function in java that converts string to byte array ?
+6
A:
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());
Jon Skeet
2009-12-16 10:04:55
for a hex string ?
silverkid
2009-12-16 10:05:45
@silverkid: You mean you want to *parse* a string of hex digits into a byte array? Editing...
Jon Skeet
2009-12-16 10:07:11
yes i have a string of hex digits that i want to convert to byte array
silverkid
2009-12-16 10:08:19
for example my string is 95A8EE8E89979B9EFDCBC6EB9797528D
silverkid
2009-12-16 10:09:31
Using the deprecated version of the getBytes method is 10x faster than newer, correct versions. We use the older method in logging code where encoding issues are not a concern. ref: http://java.sun.com/developer/technicalArticles/Programming/Performance/
Jim Rush
2009-12-16 12:16:15
Where can encoding issues not be a concern? If you don't care about the output, why bother calling the method? I'd also question the wisdom of trusting performance advice from 12 years ago...
Jon Skeet
2009-12-16 13:55:28