Server-Client数据传送的问题

Question

服务器端代码:
import java.io.*;
import java.net.*;
class Server{
public static void main(String[] args) throws Exception{
ServerSocket serverTalk = new ServerSocket(2000);
System.out.println("监听本机的2000端口");
Socket clientTalk;
clientTalk = serverTalk.accept();
System.out.println("一个客户端连接上来了");

InputStream in = clientTalk.getInputStream();
OutputStream out = clientTalk.getOutputStream();

BufferedReader br = new BufferedReader(new InputStreamReader(in));
PrintStream ps = new PrintStream(out);
//BufferedWriter ps = new BufferedWriter(new OutputStreamWriter(out));

String msg ;

while((msg=br.readLine())!=null ){

System.out.println("服务器接受到:" + msg);

ps.println(msg);
//ps.write(msg);
if(msg.equals("quit")){
System.out.println("服务器程序退出:");
break;
}
} 
in.close();
out.close();
clientTalk.close();  }
}客户端代码:
import java.io.*;
import java.net.*;
class Client{
public static void main(String[] args) throws Exception{
Socket clientTalk = new Socket("127.0.0.1",2000);
System.out.println("已连上服务器");
InputStream in = clientTalk.getInputStream();
OutputStream out = clientTalk.getOutputStream();

BufferedReader br1 = new BufferedReader(new InputStreamReader(in));
PrintStream ps = new PrintStream(out);
//BufferedWriter ps = new BufferedWriter(new OutputStreamWriter(out));

BufferedReader br2 = new BufferedReader(new InputStreamReader(System.in));

String msg;

while((msg = br2.readLine())!=null){
 ps.print(msg);
 //ps.write(msg);
 System.out.println("向服务器发送:" + msg);
 if(msg.equals("quit")){
  System.out.println("客户端退出:");
  in.close();
  out.close();
  clientTalk.close();
  break;
 }
}


}
}问题:为什么从客户端发送的数据,服务器端没有接受到呢