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

public class FileChannelTest3 {

    public FileChannelTest3(String srcFilename, String destFilename) {
        System.out.println("どちらの方法でコピーしますか");
        System.out.println("1: TransferTo 2: TransferFrom");
        System.out.print("> ");
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        try{
            String inputText = reader.readLine();

            if (inputText.equals("1")) {
                copyUsingTransferTo(srcFilename, destFilename);
            }else if (inputText.equals("2")) {
                copyUsingTransferFrom(srcFilename, destFilename);
            }
        }catch(IOException ex){
            ex.printStackTrace();
        }
    }

    private void copyUsingTransferTo(String srcFilename, String destFilename){
        System.out.println("TransferTo を使用してコピーを行います");

        try{
            FileInputStream in = new FileInputStream(srcFilename);
            FileChannel inputChannel = in.getChannel();

            FileOutputStream out = new FileOutputStream(destFilename);
            FileChannel outputChannel = out.getChannel();

            inputChannel.transferTo(0, (int)inputChannel.size(), outputChannel);

            outputChannel.close();
            inputChannel.close();

        }catch(FileNotFoundException ex){
            ex.printStackTrace();
        }catch(IOException ex){
            ex.printStackTrace();
        }
    }

    private void copyUsingTransferFrom(String srcFilename, String destFilename){
        System.out.println("TransferTo を使用してコピーを行います");

        try{
            FileInputStream in = new FileInputStream(srcFilename);
            FileChannel inputChannel = in.getChannel();

            FileOutputStream out = new FileOutputStream(destFilename);
            FileChannel outputChannel = out.getChannel();

            outputChannel.transferFrom(inputChannel, 0, (int)inputChannel.size());

            outputChannel.close();
            inputChannel.close();

        }catch(FileNotFoundException ex){
            ex.printStackTrace();
        }catch(IOException ex){
            ex.printStackTrace();
        }
    }

    public static void main(String[] args){
        new FileChannelTest3(args[0], args[1]);
    }
}