Converting A String To Hexadecimal In Java

Question

I am trying to convert a string like \"testing123\" into hexadecimal form in java. I am currently using BlueJ.

And to convert it back, is it the same thing except b

Answer 1

byte[] bytes = string.getBytes(CHARSET); // you didn't say what charset you wanted
BigInteger bigInt = new BigInteger(bytes);
String hexString = bigInt.toString(16); // 16 is the radix

You could return hexString at this point, with the caveat that leading null-chars will be stripped, and the result will have an odd length if the first byte is less than 16. If you need to handle those cases, you can add some extra code to pad with 0s:

StringBuilder sb = new StringBuilder();
while ((sb.length() + hexString.length()) < (2 * bytes.length)) {
  sb.append("0");
}
sb.append(hexString);
return sb.toString();