Java 为什么我不能使用DataOutputStream两次？

我曾两次尝试向服务器发送消息，但始终出错。我不知道我该怎么做才能使这件事成功。我一直在这行“msgToServer.witeBytes（“GETACCESS”+jTextFieldUsername.getText（）+“”+jTextFieldPassword.getText（）+“\n”）上出错

客户：

try {
        s = new Socket("localhost", 6000);

        Socket incoming;
        incoming = s;
     
        msgFromServer = new BufferedReader(new InputStreamReader(incoming.getInputStream()));
        msgToServer = new DataOutputStream(incoming.getOutputStream());

        msgToServer.writeBytes("LOGIN "+jTextFieldUsername.getText()+" "+jTextFieldPassword.getText()+"\n");
        
        String result;
        result = msgFromServer.readLine();

        if(result.equals("TRUE")){
            JOptionPane.showMessageDialog(null,"Client Access is granted");
        }
        else if(result.equals("False")){
            JOptionPane.showConfirmDialog(this, "Client Access is not granted");
        }
        msgToServer.writeBytes("GETACCESS"+ jTextFieldUsername.getText() + " "+ jTextFieldPassword.getText() + "\n");
        String h1;
        h1 = msgFromServer.readLine();
        JOptionPane.showConfirmDialog(this, "hl: "+h1);
        if(h1.equals("Teacher")){
            
            refreshTable(2);
            JOptionPane.showConfirmDialog(this, "You were granted as a lecturer");
        }
        else if(h1.equals("Student")){
            refreshTable(1);
            JOptionPane.showConfirmDialog(this, "You were granted as a student");
        }

    } catch (IOException ex) {
        Logger.getLogger(presensiClientFrame.class.getName()).log(Level.SEVERE, null, ex);
    }

我的错误：

java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream.java:210)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
at java.io.InputStreamReader.read(InputStreamReader.java:184)
at java.io.BufferedReader.fill(BufferedReader.java:161)
at java.io.BufferedReader.readLine(BufferedReader.java:324)
at java.io.BufferedReader.readLine(BufferedReader.java:389)

---

//..

服务器阻塞直到客户端连接到它，然后再次阻塞以侦听来自客户端的消息，在单个消息之后，它关闭连接，因为代码不处理连续性。要保持持续的通信活动，您需要执行读、写操作

            String inputLine;
            while ((inputLine = msgFromServer.readLine()) != null) {
                if (".".equals(inputLine)) {
                    out.println("bye");
                    break;
                }
                msgToServer.writeBytes("GETACCESS"+ jTextFieldUsername.getText() + " "+ jTextFieldPassword.getText() + "\n");
            }

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如果你不告诉我们你犯了什么错误，我们帮不了你多少忙。