是否可以从List创建ByteBuffer <ByteBuffer> ？

Question

Let's say i have a list/arrayList or an array of ByteBuffers ( List<ByteBuffer> or ByteBuffer[] )

It is possible from this to directly get the bytes from the above array without iterating through all the items or computing their total size? I am looking for something like this:

ByteBuffer[] bufferList = new ByteBuffer[7]; //this can be any kind of list of ByteBuffers
//add items to the array
ByteBuffer buffer = (ByteBuffer) bufferList; //what i want to achieve  

Of course the last line is not correct.

The thing is that i already have in the array all the bytes in order, but I want them not to be in a list anymore, but in a single ByteBuffer. So is there something that makes possible to create a ByteBuffer from a list/array of ByteBuffers?

Thank you!

Answer 1

public ByteBuffer convertToOne(ByteBuffer[] src)
{
    int size=0;
    for(int i = 0 ; i < src.length ; i++) {
        size+=src[i].array().length;
    }

    ByteBuffer newBuffer = ByteBuffer.allocate(size);

    int sizeAt = 0;
    for(int i = 0 ; i < src.length ; i++) {
        newBuffer.put(src[i].array(), sizeAt);
        sizeAt += src[i].array().length;
    }
    return newBuffer;
}

Answer 2

I believe you're going to have to create a new ByteBuffer and copy each of the buffers in bufferList into the new one. You should put this functionality in a method so as to not repeat the code each time you use it.