CODEWITHSUNDEEP
java
beginsheinyani
beginsheinyani

Reputation: 55

convert int or long to byte hex array

what is the easiest way to convert an integer or a long value to a byte buffer?

example:

input : 325647187

output : {0x13,0x68,0xfb,0x53}

I have tried a ByteBuffer like this : 

ByteBuffer buffer = ByteBuffer.allocate(4);
buffer.putLong(325647187);

byte[] x=buffer.array();

for(int i=0;i<x.length;i++)
{
    System.out.println(x[i]);
}

but I get exception

Exception in thread "main" java.nio.BufferOverflowException
    at java.nio.Buffer.nextPutIndex(Buffer.java:527)
    at java.nio.HeapByteBuffer.putLong(HeapByteBuffer.java:423)
    at MainApp.main(MainApp.java:11)

Upvotes: 1

Views: 740

Answers (2)

Francis
Francis

Reputation: 94

you can try this for an easier way of converting:

so you have 325647187 as your input, we can then have something like this

byte[] bytes = ByteBuffer.allocate(4).putInt(325647187).array();

for (byte b : bytes) 
{
System.out.format("0x%x ", b);
}

for me this is(if not the most) an efficient way of converting to byte buffer.

Upvotes: 0

Eran
Eran

Reputation: 394156

You allocated a 4 bytes buffer, but when calling putLong, you attempted to put 8 bytes in it. Hence the overflow. Calling ByteBuffer.allocate(8) will prevent the exception.

Alternately, if the encoded number is an integer (as in your snippet), it's enough to allocate 4 bytes and call putInt().

Upvotes: 6

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