Java integer to fixed length byte array

Question

How can I convert an integer between 0 and 65k to fixed length of two bytes? as an example

2 would be 00000000 00000010

~65k would be 11111111 11111111

and all that in a byte array

reos · Accepted Answer · 2017-03-08 13:45:47Z

1

java has the short data type, this is a 2 bytes integer. You cast the integer to short.

int a = 1;
short b = (short)a;

If you want the bytes of the integer you can use ByteBuffer

byte[] bytes = ByteBuffer.allocate(2).putShort((short)intnumber).array();

Or if you want the binary format you can just use toBinaryString method of the Integer.

int x = 2;
System.out.println(Integer.toBinaryString(x));

answered Mar 8, 2017 at 13:34

reos

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2 Comments

I think the middle one is what I'm looking for, but it throws an BufferOverflow Exception in my case

Yes, Just use ByteBuffer.allocate(2).putShort((short)1);

Markus Benko · Accepted Answer · 2017-03-08 13:47:57Z

0

When x is your number between 0 and 65,535 just use

new byte[] { (byte) (x >> 8), (byte) x }

to create a byte array containing the value as two bytes in big-endian format.

answered Mar 8, 2017 at 13:47

Markus Benko

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