NIO og View Buffer'e

jeg skal ikke selv kunne udtale mig om det men måske giver dette mening for dig:

http://javadiff.sourceforge.net/jdiff/reports/j2se140_j2se141_docs/changes/docdiffs_java.nio.html >
A view buffer is potentially much more efficient because it will be direct if and only if its backing byte buffer is direct.

Java New IO High Performance Java IO And Regular Expressions - Ron Hitchens

View buffers can potentially be much more efficient when derived from direct byte buffers. If the byte
order of the view matches the native hardware byte order, the low level code may be able to access the
data values directly rather than going through the byte packing and unpacking process.

->simonvalter: Takker.

Eget eks.:

import java.io.*;
import java.nio.*;
import java.nio.channels.FileChannel;

public class Bytebuffer {
    public static void main(String[] args) throws IOException {
        // Opretter fil og channel
        //File f=new File("h:/java/projects/diverse/bytebuffer.dat");
        File f=new File("c:/dat/bytebuffer.dat");
        boolean bo=f.createNewFile();
        FileOutputStream fos=new FileOutputStream(f);
        FileChannel fc=fos.getChannel();
        int totantal=1000000; // Total antal records
        int antal=100; // Antal records i buffer'en
        int[] i=new int[5];
        double[] d=new double[5];
        byte[] c=new byte[5]; //char[] c=new char[5];
        long starttid = System.currentTimeMillis();
        ByteBuffer buf = ByteBuffer.allocate(antal*(4*i.length+8*d.length+1*c.length)); // 2*c.length
        // Opretter arrays der skal skrives til buffer
        int _totantal=0;
        for (;;) {
            i[0]=1;
            i[1]=2;
            i[2]=3;
            i[3]=4;
            i[4]=5;
            d[0]=1.1;
            d[1]=2.1;
            d[2]=3.1;
            d[3]=4.1;
            d[4]=5.1;
            c[0]=(byte)'A';
            c[1]=(byte)'B';
            c[2]=(byte)'Æ';
            c[3]=(byte)'Ø';
            c[4]=(byte)'+';
            for (int k=0;k<antal;k++) {
                buf.position(buf.position()+4*buf.asIntBuffer().put(i).position());
                buf.position(buf.position()+8*buf.asDoubleBuffer().put(d).position());
                buf.put(c); //buf.position(buf.position()+2*buf.asCharBuffer().put(c).position());
            }
            buf.flip();       
            fc.write(buf);
            buf.clear();
            _totantal=_totantal+antal;
            if (_totantal==totantal) break;
        }
        fos.close();
        long sluttid = System.currentTimeMillis();
        System.out.println("Tidsforbrug "+ (sluttid-starttid)*0.001 +" sek.");
    }   
}

Lukker spm.