RTF到HTML的自由电子表格-Java

我正在尝试使用Libre将RTF转换为HTML。对于Libre文档，它可以正常工作，但对于电子表格，它的值为空。下面是我如何进行解析的java代码

ArrayList<String> styleValue = new ArrayList<String>();
String result;
Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
Transferable contents = clipboard.getContents(null);
DataFlavor dfRTF = new DataFlavor("text/rtf", "Rich Formatted Text");
DataFlavor dfTxt = DataFlavor.stringFlavor;
result = rtfToHtml(new StringReader(streamToString((InputStream) contents.getTransferData(dfRTF))));

如果有人能帮我修改Libre电子表格，我将不胜感激。请给我一些建议

public static String rtfToHtml(Reader rtf) throws IOException { 
        JEditorPane p = new JEditorPane();
        p.setContentType("text/rtf");
        EditorKit kitRtf = p.getEditorKitForContentType("text/rtf");
        try {
            kitRtf.read(rtf, p.getDocument(), 0);
            kitRtf = null;
            EditorKit kitHtml = p.getEditorKitForContentType("text/html");
            Writer writer = new StringWriter();
            kitHtml.write(writer, p.getDocument(), 0, p.getDocument().getLength());
            return writer.toString();

        } catch (BadLocationException e) {
            e.printStackTrace();
        }
        return null;
    }