In Java program I have signed byte array as
[-112, 21, 64, 0, 7, 50, 54, 127]
how i can convert into ascii number which is equal to
901540000732367F
-
What do you mean by "ascii number"? Do you actually mean hexadecimal number?František Žiačik– František Žiačik2020-10-09 18:14:37 +00:00Commented Oct 9, 2020 at 18:14
-
yes hexadecimal numberNRaj– NRaj2020-10-09 18:15:48 +00:00Commented Oct 9, 2020 at 18:15
Add a comment
|
2 Answers
It seems that the order of bytes in the result is reverse to that of the array, so you should iterate the array in the reverse order and add each element with a shift by the predefined number of bits:
private static String convertToHexFullByte(byte[] arr) {
return convertToHex(arr, 8);
}
private static String convertToHexHalfByte(byte[] arr) {
return convertToHex(arr, 4);
}
private static String convertToHex(byte[] arr, int bits) {
long mask = 0;
for (int i = 0; i < bits; i++) {
mask |= 1 << i;
}
long res = 0;
for (int i = arr.length - 1, j = 0; i >= 0; i--, j += bits) {
res |= (arr[i] & mask) << j;
}
return Long.toHexString(res).toUpperCase();
}
Test
public static void main(String args[]) {
byte[] arr4 = {49, 55, 48, 51, 55};
System.out.println(convertToHexHalfByte(arr4));
byte[] arr8 = {-112, 21, 64, 0, 7, 50, 54, 127};
System.out.println(convertToHexFullByte(arr8));
}
output
17037
901540000732367F
4 Comments
NRaj
Its givinf me this ffffffff9747767f
Nowhere Man
@NRaj yes, fixed that
NRaj
Its working, btw why its not working for another {49, 55, 48, 51, 55}; which should be 17037
Nowhere Man
How come? You have 5 positive bytes as input and the result is supposed to be 3 bytes?
Try this. It works by:
- streaming the indices of the byte array
- maping to an int and getting rid of the sign extension
- reducing to a long by shift and or operations.
byte[] bytes = { -112, 21, 64, 0, 7, 50, 54, 127 };
long lng = IntStream.range(0, bytes.length)
.mapToLong(i -> bytes[i] & 0xff)
.reduce(0L, (a, b) -> (a << 8) | b);
System.out.println("long decimal value = " + lng);
System.out.println("long hex value = " + Long.toHexString(lng));
prints
long decimal value = -8064469188872096129
long hex value = 901540000732367f
Using the same technique, the other example of {49, 55, 48, 51, 55}
should be:
long decimal value = 211379303223
long hex value = 3137303337
2 Comments
NRaj
Yes its working, but when i will have unsigned array {49, 55, 48, 51, 55}; => 17037 how to handle. can i use same solution for signed and unsigned byte array.
WJS
Yes, it will work. But
17037 is not a hex conversion it is the last digit of [31,37,30,33,37] which is the hex value of each byte.