问题
I would like to extract a set of coordinates from a byte array into a DoubleBuffer.
Below is an example of how I extract a set of coordinates from the main byte array into another byte array.
byte intPoints[] = new byte[4];
byte geomCoords[];
...
is = new ByteArrayInputStream(stmt.column_bytes(0)); //reads the polygon from db
...
is.read(intPoints); //intPoints now holds the number of points in the polygon
//After this is read the actual coordinate list is next
//Set the size of geomCoords to hold all coordinates,
//There are 2 coordinates per point and each coordinate is a double value(8 bytes)
geomCoords = new byte[ByteBuffer.wrap(intPoints).order(endian).getInt() * 2 * 8];
is.read(geomCoords); //geomCoords now holds all the coordinates for the polygon
My questions are:
How can I get geomCoords byte array into a DoubleBuffer?
Or
Can I get this data into a DoubleBuffer without the creation of geomCoords? Speed and efficiency is key, so any shortcut or optimization is most welcome!
回答1:
If you know that the 8 bytes in the bytes buffer are indeed Doubles, then simply
DoubleBuffer dbls = new ByteBuffer(geomCoords).asDoubleBuffer();
Now each point can be extracted with dbls.get();
来源:https://stackoverflow.com/questions/17391944/how-to-get-a-byte-array-data-into-doublebuffer