使用线程的套接字写入错误

我有以下课程

ClientDemo.java

ClientTread.java

ServerDemo.java

ServerThread.java

 public class ClientDemo {
   public static void main(String[] args) throws InterruptedException {
     try {
        Socket client=new Socket("localhost", 6666);
        while(true)
        {
            System.out.println("Hello");
            Thread th=new Thread(new ClientThread(client));
            th.start();
            System.out.println("Thread started........");
            th.sleep(1000*30);

        }

     } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
     }
    }

   }

ClientThread.java

 public class ClientThread implements Runnable {
   Socket c;
    public ClientThread(Socket client) {
    this.c=client;
}

@Override
public void run() {
    DataOutputStream dos=null;
    try {
        System.out.println("Client thread is going to write.......");
        dos = new DataOutputStream(c.getOutputStream());
        dos.writeUTF("Hello From Client");
        System.out.println("Data written by client............");
    } catch (IOException e) {
        // TODO Auto-generated catch block
        //e.printStackTrace();
        System.out.println(e+"");
    }


      }

    }

SeverDemo.java

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

    ServerSocket serversocket=new ServerSocket(6666);
    System.out.println("server listening..........");
    Thread ts=new Thread( new ServerThread(serversocket.accept()));
    ts.start();
    System.out.println("server thread started.........");
            } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
        }
     }
    }

ServerThread.java

 public class ServerThread implements Runnable {
Socket s;

public ServerThread(Socket server) {
    this.s=server;
}

@Override
public void run() {
    DataInputStream dis;
    try {
        dis = new DataInputStream(s.getInputStream());
        String message=dis.readUTF();
        System.out.println(message);

    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }



}

}

该代码执行一次完美，之后我得到以下错误

在客户端控制台中

Hello

Thread started........

Client thread is going to write.......

Data written by client............

Hello

Thread started........

Client thread is going to write.......

java.net.SocketException: Connection reset by peer: socket write error