关于网络编程的一点困惑

  昨天光写程序了，没有写学习日记。做了一个服务器，一个客户端。现在的问题是，当客户端与服务器建立连接后，只能发送一条信息，之后就断开连接。

连接创建了另外一个线程，用于同步接收数据，但是传输一条数据之后，连接就断开了。这应该是线程问题。死循环的语句，应该一直执行才对。

  多看点书，继续调试。。。看样子基础不够

class a
{
    a()
    {
          new Thread(new Runnable()
               {
                   public void run()
                    {
                        while(true){
                
        if(client!=null)
            jButton2.setEnabled(true);
                           while(true){
                        DataInputStream in=null;
                   
                if(client==null)
                {
                    jTextArea1.setText("未建立连接！/n");
                }
                else
                {
                    try {
                         in=new DataInputStream(client.getInputStream());
                        String rec=in.readUTF();
                        jTextArea1.setText(client.getInetAddress()+"  "+client.getPort()+"说："+rec+jTextArea1.getText());
                       
                    } catch (Exception ex) {
                       
                    }
                }
                       
                try {
                 in.close();
                } catch (IOException ex) {
                  
                }
                          }
                        }  }
                }).start();
    }

}
    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                        
        // TODO add your handling code here:
                 try {
            client=new Socket(InetAddress.getByName(jTextField1.getText()),3555);
        } catch (IOException ex) {
            Logger.getLogger(clientj.class.getName()).log(Level.SEVERE, null, ex);
        }
       new a().start();
    }