如何制作高度相对于内容长度，但宽度恒定的JTextArea块？

JTextArea textArea = new JTextArea();
textArea.setPreferredSize(new Dimension(fixedWidth, initialHeight));

JScrollPane scrollPane = new JScrollPane(textArea);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);

textArea.getDocument().addDocumentListener(new DocumentListener() {
    @Override
    public void insertUpdate(DocumentEvent e) {
        updateTextAreaHeight();
    }

    @Override
    public void removeUpdate(DocumentEvent e) {
        updateTextAreaHeight();
    }

    @Override
    public void changedUpdate(DocumentEvent e) {
        updateTextAreaHeight();
    }

    private void updateTextAreaHeight() {
        int lineCount = textArea.getLineCount();
        int lineHeight = textArea.getFontMetrics(textArea.getFont()).getHeight();
        int newHeight = lineCount * lineHeight;
        textArea.setPreferredSize(new Dimension(fixedWidth, newHeight));
        textArea.revalidate();
    }
});