String inputFile = "1.docx";
String outputFile ="1.html";
Document doc = new Document();
doc.loadFromFile(inputFile);
doc.getHtmlExportOptions().setCssStyleSheetType(CssStyleSheetType.Internal);
doc.getHtmlExportOptions().setImageEmbedded(true);
doc.saveToFile(outputFile, FileFormat.HtmlFixed);
doc.dispose();

Document doc = ConvertUtil.GetNewEngineDocument();
doc.loadFromFile(input);
HandleDocumentSubstitutionWarnings substitutionWarningHandler = new HandleDocumentSubstitutionWarnings();
doc.setWarningCallback(substitutionWarningHandler);
doc.saveToFile(output_1);
StringBuilder sb = new StringBuilder();
Iterator iterator = substitutionWarningHandler.FontWarnings.iterator();
while(iterator.hasNext()){
    System.out.println(((WarningInfo)iterator.next()).getDescription());
}
String s = substitutionWarningHandler.FontWarnings.get(0).getDescription();
WarningSource warningSource = substitutionWarningHandler.FontWarnings.get(0).getSource();
substitutionWarningHandler.FontWarnings.clear(); 
class HandleDocumentSubstitutionWarnings implements IWarningCallback
{
    public void warning(WarningInfo info) {
        if(info.getWarningType() == WarningType.Font_Substitution)
            FontWarnings.warning(info);
    }
    public WarningInfoCollection FontWarnings = new WarningInfoCollection();
}

CompareOptions options=new CompareOptions();
Options.IgnoreHeadersAndFooters=true;//Default is false

Document doc = new Document();
//load .md file
doc.loadFromFile("input.md");
//save to .md file
doc.saveToFile("output.md", com.spire.doc.FileFormat.Markdown);
//save to .docx file
//doc.saveToFile("output.docx", com.spire.doc.FileFormat.Docx);
//save to .doc file
//doc.saveToFile("output.doc", com.spire.doc.FileFormat.Doc);
//save to .pdf file
//doc.saveToFile("output.pdf", com.spire.doc.FileFormat.PDF);
doc.close();

Document doc = new Document();
//load .docx file
doc.loadFromFile("input.docx");
//load .doc file
//doc.loadFromFile("input.doc");
//save to .md file
doc.saveToFile("output.md", com.spire.doc.FileFormat.Markdown);
doc.close();

Document document = new Document();
 document.loadFromFile(inputFile);
 String[] fieldNames = new String[]{"ImageFile"};
 String[] fieldValues = new String[]{inputFile_img};
 document.getMailMerge().MergeImageField = new MergeImageFieldEventHandler() {
     @Override
     public void invoke(Object sender, MergeImageFieldEventArgs args) {
         mailMerge_MergeImageField(sender, args);
     }
 };
 document.getMailMerge().execute(fieldNames, fieldValues);
 document.saveToFile(outputFile, FileFormat.Docx);
private static void mailMerge_MergeImageField(Object sender, MergeImageFieldEventArgs field) {
    String filePath = field.getImageFileName();
    if (filePath != null && !"".equals(filePath)) {
        try {
            field.setImage(filePath);
            field.setImageLink("https://www.baidu.com/");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

document.getFieldOptions().setCultureSource(FieldCultureSource.CurrentThread);

Document.hasDigitalSignature("filepath");

sourceDoc.integrateFontTableTo(Document destDoc);

public static void main(String[] args) {
    Document document = new Document();
    document.HtmlUrlLoadEvent = new MyDownloadEvent();
    document.loadFromFile(inputFile, FileFormat.Html, XHTMLValidationType.None);
    document.saveToFile(outputFile, FileFormat.PDF);
}
static class MyDownloadEvent extends HtmlUrlLoadHandler {
    @Override
    public void invoke(Object o, HtmlUrlLoadEventArgs htmlUrlLoadEventArgs) {
        try {
            byte[] bytes = downloadBytesFromURL(htmlUrlLoadEventArgs.getUrl());
            htmlUrlLoadEventArgs.setDataBytes(bytes);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
public static byte[] downloadBytesFromURL(String urlString) throws Exception {
    URL url = new URL(urlString);
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    connection.setRequestMethod("GET");
    connection.setConnectTimeout(5000);
    connection.setReadTimeout(5000);
    int responseCode = connection.getResponseCode();
    if (responseCode == HttpURLConnection.HTTP_OK) {
        InputStream inputStream = connection.getInputStream();
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int bytesRead;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, bytesRead);
        }
        outputStream.close();
        return outputStream.toByteArray();
    } else {
        throw new Exception("Failed to download content. Response code: " + responseCode);
    }
}

document.setCustomFonts(InputStream[] fontStreamList);

document.clearCustomFonts();

Document.setGlobalCustomFonts(InputStream[] fontStreamList);

Document.clearGlobalCustomFonts();