CODEWITHSUNDEEP
javaudpdoublearrays
Tumetsu
Tumetsu

Reputation: 1721

Convert array of doubles to bytearray in Java

In past I haven't done much of byte shifting so I'm a bit loss here. Basically I have double array of size 26 and I should send the array in one UDP packet in Java. I found some examples of how to convert one double to bytearray, but I'm not sure how to apply it to double-array.

So how this should be done? Loop through the double array and convert each double and somehow concatenating them to one bytearray?

Upvotes: 2

Views: 4264

Answers (3)

Evgeniy Dorofeev
Evgeniy Dorofeev

Reputation: 136162

Convert your doubles into a byte array using java.nio.ByteBuffer

ByteBuffer bb = ByteBuffer.allocate(doubles.length * 8);
for(double d : doubles) {
   bb.putDouble(d);
}

get the byte array

byte[] bytearray = bb.array();

send it over the net and then convert it to double array on the receiving side

ByteBuffer bb = ByteBuffer.wrap(bytearray);
double[] doubles = new double(bytearray.length / 8);
for(int i = 0; i < doubles.length; i++) {
    doubles[i] = bb.getDouble();
}

Upvotes: 7

Fildor
Fildor

Reputation: 16168

So how this should be done? Loop through the double array and convert each double and somehow concatenating them to one bytearray?

Exactly. You can make use of DoubleBuffer, perhaps. (Marko linked it in his comment)

What Marko referred to was having actually a ByteBuffer and fetching a "DoubleBuffer"-View to it. So you can put the Doubles into the DoubleBuffer View and fetch the byte[] from the original ByteBuffer.

Upvotes: 4

Steve Oh
Steve Oh

Reputation: 1159

apache httpcore provides a org.apache.http.util.ByteArrayBuffer class which my be helpful

ByteArrayBuffer buffer = new ByteArrayBuffer(26);
buffer.append(...)

Upvotes: 1

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