Example 1: Convert Byte Array to Hex value
public class ByteHex {
public static void main(String[] args) {
byte[] bytes = {10, 2, 15, 11};
for (byte b : bytes) {
String st = String.format("%02X", b);
System.out.print(st);
}
}
}
Output
0A020F0B
In the above program, we have a byte array named bytes. To convert byte array to a hex value, we loop through each byte in the array and use String's format().
We use %02X to print two places (02) of Hexadecimal (X) value and store it in the string st.
This is a relatively slower process for large byte array conversion. We can dramatically increase the speed of execution using byte operations shown below.
Example 2: Convert Byte Array to Hex value using byte operations
public class ByteHex {
private final static char[] hexArray = "0123456789ABCDEF".toCharArray();
public static String bytesToHex(byte[] bytes) {
char[] hexChars = new char[bytes.length * 2];
for ( int j = 0; j < bytes.length; j++ ) {
int v = bytes[j] & 0xFF;
hexChars[j * 2] = hexArray[v >>> 4];
hexChars[j * 2 + 1] = hexArray[v & 0x0F];
}
return new String(hexChars);
}
public static void main(String[] args) {
byte[] bytes = {10, 2, 15, 11};
String s = bytesToHex(bytes);
System.out.println(s);
}
}
The output of the program is the same as Example 1.