问java.net.SocketException:主机中的软件中止了已建立的连接。

EN

    public ServerSocket ss;
    public ArrayList<Client> Clients = new ArrayList<Client>();
    String Alphabets = "AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz0123456789";
    public Server() throws IOException 
    {
        ss = new ServerSocket(1111);
        
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setLayout(null);
        this.setResizable(false);
        this.setSize(400,150);
        this.getContentPane().setBackground(Color.BLACK);
        this.setTitle("Server");
        
        JLabel label = new JLabel("Server Running");
        label.setForeground(Color.WHITE);
        label.setBounds(15,25,350,60);
        label.setFont(new Font(Font.SANS_SERIF,Font.PLAIN,50));
        
        this.add(label);
        this.setVisible(true);
        while(true) 
        {
            Socket socket = ss.accept();
            DataOutputStream dout = new DataOutputStream(socket.getOutputStream());
            String id = getId();
            dout.writeUTF(id);
            Client c = new Client(socket,id);
            dout.close();
            dout.flush();
        }
    }
    String getId() 
    {
        Random rand = new Random();
        String id = ""; 
        for(int i = 0;i < 6;i++) 
        {
            char i3 = Alphabets.charAt(rand.nextInt(0,Alphabets.length()));
            id += i3;       
        }
        return id;
    }

    public String Connect() throws UnknownHostException, IOException 
    {
        mySocket = new Socket("localhost",1111);
        DataInputStream din = new DataInputStream(mySocket.getInputStream());
        String id = din.readUTF();
        return id;
    }

    public void SendMessage(String msg) throws IOException 
    {
        DataOutputStream dout = new DataOutputStream(s.getOutputStream());
        dout.writeUTF(msg);
        AddToMessages(Id + ": " + msg);
    }