导出为 FDF

当需要将 AcroForm 字段数据序列化为 FDF 时，使用 FormExamples.exportFdf(...)。

public static void exportFdf(Path inputFile, Path outputFile) throws Exception {
    Form form = new Form();
    try (OutputStream outputStream = Files.newOutputStream(outputFile)) {
        form.bindPdf(inputFile.toString());
        form.exportFdf(outputStream);
    } finally {
        form.close();
    }
}