[java] Hex-encoded String to Byte Array

String str = "9B7D2C34A366BF890C730641E6CECF6F";

I want to convert str into byte array, but str.getBytes() returns 32 bytes instead of 16.

I know it's late but hope it will help someone else...

This is my code: It takes two by two hex representations contained in String and add those into byte array. It works perfectly for me.

public byte[] stringToByteArray (String s) {
    byte[] byteArray = new byte[s.length()/2];
    String[] strBytes = new String[s.length()/2];
    int k = 0;
    for (int i = 0; i < s.length(); i=i+2) {
        int j = i+2;
        strBytes[k] = s.substring(i,j);
        byteArray[k] = (byte)Integer.parseInt(strBytes[k], 16);
        k++;
    }
    return byteArray;
}

That should do the trick :

byte[] bytes = toByteArray(Str.toCharArray());

public static byte[] toByteArray(char[] array) {
    return toByteArray(array, Charset.defaultCharset());
}

public static byte[] toByteArray(char[] array, Charset charset) {
    CharBuffer cbuf = CharBuffer.wrap(array);
    ByteBuffer bbuf = charset.encode(cbuf);
    return bbuf.array();
}

Java SE 6 or Java EE 5 provides a method to do this now so there is no need for extra libraries.

The method is DatatypeConverter.parseHexBinary

In this case it can be used as follows:

String str = "9B7D2C34A366BF890C730641E6CECF6F";
byte[] bytes = DatatypeConverter.parseHexBinary(str);

The class also provides type conversions for many other formats that are generally used in XML.

I assume what you need is to convert a hex string into a byte array that equals that means the same thing as that hex string? Adding this method should do it for you, without any extra library importing:

public static byte[] hexToByteArray(String s) {
     String[] strBytes = s.split("(?<=\\G.{2})");
     byte[] bytes = new byte[strBytes.length];
     for(int i = 0; i < strBytes.length; i++)
         bytes[i] = (byte)Integer.parseInt(strBytes[i], 16);
     return bytes;
}

try this:

     String str = "9B7D2C34A366BF890C730641E6CECF6F";
     String[] temp = str.split(",");
     bytesArray = new byte[temp.length];
     int index = 0;
     for (String item: temp) {
     bytesArray[index] = Byte.parseByte(item);
     index++;
     }

Use:

str.getBytes("UTF-16LE");