Convert ByteBuffer to byte array java [duplicate]

问题:

This question already has answers here:

Gets byte array from a ByteBuffer in java (6 answers)

Closed 4 years ago.

Does anyone know how to convert ByteBuffer to byte[] array? I need to get byte array from my ByteBuffer. When I run bytebuffer.hasArrray() it returns no. Every question I looked so far is converting byte array to byteBuffer, but I need it other way around. Thank you.

回答1:

ByteBuffer exposes the bulk get(byte[]) method which transfers bytes from the buffer into the array. You'll need to instantiate an array of length equal to the number of remaining bytes in the buffer.

ByteBuffer buf = ...
byte[] arr = new byte[buf.remaining()];
buf.get(arr);

回答2:

If hasArray() reports false then, calling array() will throw an exception.

In that case, the only way to get the data in a byte[] is to allocate a byte[] and copy the bytes to the byte[] using get(byte) or similar.