package nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;

public class SocketChannelDemo {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        try {
            SocketChannel socketChannel = SocketChannel.open();
            socketChannel.connect(new InetSocketAddress("127.0.0.1", 9999));

            ByteBuffer bb = ByteBuffer.allocate(48);
            int byteNum;

            int bytes = socketChannel.read(bb);
            bb.flip();
            while (bb.hasRemaining()) {
                System.out.print((char) bb.get());
            }
            bb.clear();
            
            socketChannel.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

package nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;

public class ServerSocketChannelDemo {
    public static void main(String[] args) {

        try {
            ServerSocketChannel ssc = ServerSocketChannel.open();
            ssc.socket().bind(new InetSocketAddress(9999));
            String msg = "send something to you";
            ByteBuffer bb = ByteBuffer.allocate(48);
            bb.clear();
            bb.put(msg.getBytes());
            bb.flip();
            while (true) {
                SocketChannel socketChannel = ssc.accept();
                while (bb.hasRemaining()) {
                    socketChannel.write(bb);
                }
                socketChannel.close();
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
}