怎么判断doc文档有没有加水印？最好是aspose.words

判断一个doc文档有没有加水印
aspose.words里有个删除水印的方法，是根据页眉页脚判断 删掉的花页眉页脚也就删掉了，不能直接判断是否添加了水印 有没有针对水印的方法

/**
 * 移除全部水印
 * @param doc
 * @throws Exception
 */
private static void removeWatermark(Document doc) throws Exception {
    for (Section sect : doc.getSections()) {
        // There could be up to three different headers in each section, since we want
        // the watermark to appear on all pages, insert into all headers.
        removeWatermarkFromHeader(sect, HeaderFooterType.HEADER_PRIMARY);
        removeWatermarkFromHeader(sect, HeaderFooterType.HEADER_FIRST);
        removeWatermarkFromHeader(sect, HeaderFooterType.HEADER_EVEN);
    }
}
/**
 * 移除指定Section的水印
 * @param sect
 * @param headerType
 * @throws Exception
 */
private static void removeWatermarkFromHeader(Section sect, int headerType) throws Exception {
    HeaderFooter header = sect.getHeadersFooters().getByHeaderFooterType(headerType);
    if (header != null) {
        header.removeAllChildren();
    }
}