socket in java -client

package haolei.socket;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class Client {

 /**
  * @param args
  */
 public static void main(String[] args) {

  Socket st = null;
  PrintWriter pw = null;
  BufferedReader br = null;
  String ip = null;
  int port;
  String ser = null;

  try {
   st = new Socket("127.0.0.1", 4545);
   br = new BufferedReader(new InputStreamReader(st.getInputStream()));
   pw = new PrintWriter(st.getOutputStream());
   
   ser = br.readLine();
   
   while(ser.equals("ok")){
    pw.println("cmd");
    pw.println("3");
    pw.flush();
    break;
   }
   pw.close();
   br.close();
   st.close();
  } catch (IOException e) {
   e.printStackTrace();
  }

 }

}