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

import static java.nio.channels.Channels.*;

public class MainClass {

    static void genFile(File file){
        try {
            System.out.println("Generating file");
            OutputStream stream = new FileOutputStream(file);
            long size = 400000000;
            long position = 0;
            byte[] buffer = new byte[10*1024];
            Random rnd = new Random();
            for (int i = 0; i < buffer.length; i++){
                buffer[i] = (byte)rnd.nextInt();
            }
            while (position<size){
                stream.write(buffer);
                position += buffer.length;
            }
            stream.close();
            System.out.println("Done");
        } catch (IOException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        }
    }

    static void copyFileBlocks(File input, File output) throws IOException{
        InputStream inp = new FileInputStream(input);
        OutputStream outp = new FileOutputStream(output);
        byte[] buffer = new byte[128*1024];
        while (inp.available()>0){
            int read = inp.read(buffer);
            outp.write(buffer,0,read);
        }
        inp.close();
        outp.close();
    }

    static void copyFileNIO(File input, File output) throws IOException{
        FileInputStream inp = new FileInputStream(input);
        FileOutputStream outp = new FileOutputStream(output);
        FileChannel reader = inp.getChannel();
        FileChannel writer = outp.getChannel();
        long position = 0;
        while (position<reader.size()){
            position+=reader.transferTo(position, 128*1024, writer);
        }
        inp.close();
        outp.close();
    }

    static void copyFileNIOSingle(File input, File output) throws IOException{
        FileInputStream inp = new FileInputStream(input);
        FileOutputStream outp = new FileOutputStream(output);
        FileChannel reader = inp.getChannel();
        FileChannel writer = outp.getChannel();
        reader.transferTo(0, reader.size(), writer);
        inp.close();
        outp.close();
    }

    public static void main(String[] argv){
        try {
            genFile(new File("input.dat"));
            long tick;

            for (int i = 0; i < 5; i++){
                tick = System.currentTimeMillis();
                copyFileBlocks(new File("input.dat"), new File("output1.dat"));
                System.out.println("copyFileBlocks took "+(System.currentTimeMillis() - tick));

                tick = System.currentTimeMillis();
                copyFileNIO(new File("input.dat"), new File("output2.dat"));
                System.out.println("copyFileNIO took "+(System.currentTimeMillis() - tick));

                tick = System.currentTimeMillis();
                copyFileNIOSingle(new File("input.dat"), new File("output3.dat"));
                System.out.println("copyFileNIOSingle took "+(System.currentTimeMillis() - tick));
            }
        } catch (IOException e) {
            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
        }

    }
}