DouKaku?

import    java.io.InputStream;
import    java.io.OutputStream;
import    java.net.Socket;

class Echo {
    Socket    socket;
    OutputStream    out;
    InputStream    in;
    
    public Echo(String host,int port) throws Exception {
        socket = new Socket(host,port);
        out = socket.getOutputStream();
        in = socket.getInputStream();
    }
    
    public void echo(int size,byte[] request) throws Exception {
        byte[] response= new byte[size];
        out.write(request,0,size);
        out.flush();
        in.read(response,0,size);
        System.out.write(response,0,size);
    }
    
    public void close() throws Exception {
        socket.close();
    }
    
    public static void main(String[] args) {
        try {
            Echo    echo = new Echo(args[0],Integer.parseInt(args[1]));
            byte[]    request = new byte[2048];
            int    size;
            while ((size = System.in.read(request)) > 0) {
                echo.echo(size,request);
            }
            echo.close();
        } catch(Exception ex) {
            ex.printStackTrace();
        }
    }
}