将图像插入现有的非空pdf

Insert Image to existing non-empty pdf

我正在尝试使用 apache PDFBOX 将图像保存到现有的 pdf 中,但是我的内容被删除了,当我将图像放在 pdf 顶部时我得到空白文档,这个问题有解决方案吗?

我的代码是这样的。

    public class TestPdfImage {
        public static void main(String args[]) throws Exception {
              //Loading an existing document
              File file = new File("...../mydoc.pdf");
              PDDocument doc = PDDocument.load(file);

              //Retrieving the page
              PDPage page = doc.getPage(0);

              //Creating PDImageXObject object
              PDImageXObject pdImage = PDImageXObject.createFromFile("...../sample.png",doc);

              //creating the PDPageContentStream object
              PDPageContentStream contents = new PDPageContentStream(doc, page);

              //Drawing the image in the PDF document
              contents.drawImage(pdImage, 70, 250);

              System.out.println("Image inserted");

              //Closing the PDPageContentStream object
              contents.close();     

              //Saving the document
              doc.save(".../sample.pdf");

              //Closing the document
              doc.close();

           }

    }

尝试使用append-mode

//creating the PDPageContentStream object
PDPageContentStream contents = new PDPageContentStream(doc, page, AppendMode.APPEND, true);

编辑

TilmanHausherr 提到

new PDPageContentStream(doc, page, AppendMode.APPEND, true, true);

Thats why