Java 实现 pdf文件添加 图片水印 itextpdf 5.5.2

/**
 * pdf文件添加 图片水印
 *
 * @param sourceFilePath    源文件路径
 * @param fileWaterMarkPath 水印生成文件路径
 * @return
 * @throws Exception
 */
public static void setWaterMarkForPDF(String sourceFilePath, String fileWaterMarkPath) throws Exception {
    PdfReader reader = new PdfReader(sourceFilePath);
    PdfStamper stamp = new PdfStamper(reader, new FileOutputStream(fileWaterMarkPath));

    int total = reader.getNumberOfPages() + 1;
    PdfContentByte content;
    Image img = Image.getInstance("../platform/baseapi/fmsapi/conf/watermark/small.png");
    img.setAbsolutePosition(30, 100);
    for (int i = 1; i < total; i++) {
        content = stamp.getOverContent(i);// 在内容上方加水印
        content.addImage(img);
    }
    stamp.close();
    reader.close();
}