我正在尝试使用 PDFBox 向 PDF 添加水印。我已经能够让图像出现在每个页面上，但它会失去背景透明度，因为它看起来好像 PDJpeg 将其转换为 JPG。也许有一种方法可以使用 PDXObjectImage 来做到这一点。
这是我到目前为止所写的：
public static void watermarkPDF(PDDocument pdf) throws IOException
{
// Load watermark
BufferedImage buffered = ImageIO.read(new File("C:\\PDF_Test\\watermark.png"));
PDJpeg watermark = new PDJpeg(pdf, buffered);
// Loop through pages in PDF
List pages = pdf.getDocumentCatalog().getAllPages();
Iterator iter = pages.iterator();
while(iter.hasNext())
{
PDPage page = (PDPage)iter.next();
// Add watermark to individual page
PDPageContentStream stream = new PDPageContentStream(pdf, page, true, false);
stream.drawImage(watermark, 100, 0);
stream.close();
}
try
{
pdf.save("C:\\PDF_Test\\watermarktest.pdf");
}
catch (COSVisitorException e)
{
e.printStackTrace();
}
}
更新的答案（更好的版本，带有简单的水印方法，感谢下面的评论员和@okok，他们提供了他的答案）
如果您使用PDFBox 1.8.10或更高版本，您可以轻松地向PDF文档添加水印，并更好地控制需要添加水印的页面。假设您有一个带有水印图像的一页 PDF 文档，您可以将其覆盖在要添加水印的文档上，如下所示。
使用 1.8.10 的示例代码
import java.util.HashMap;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.util.Overlay;
public class TestPDF {
public static void main(String[] args) throws Exception{
PDDocument realDoc = PDDocument.load("originaldocument.pdf");
//the above is the document you want to watermark
//for all the pages, you can add overlay guide, indicating watermark the original pages with the watermark document.
HashMap<Integer, String> overlayGuide = new HashMap<Integer, String>();
for(int i=0; i<realDoc.getPageCount(); i++){
overlayGuide.put(i+1, "watermark.pdf");
//watermark.pdf is the document which is a one page PDF with your watermark image in it. Notice here that you can skip pages from being watermarked.
}
Overlay overlay = new Overlay();
overlay.setInputPDF(realDoc);
overlay.setOutputFile("final.pdf");
overlay.setOverlayPosition(Overlay.Position.BACKGROUND);
overlay.overlay(overlayGuide,false);
//final.pdf will have the original PDF with watermarks.
使用 PDFBox 2.0.0 候选版本的示例
import java.io.File;
import java.util.HashMap;
import org.apache.pdfbox.multipdf.Overlay;
import org.apache.pdfbox.pdmodel.PDDocument;
public class TestPDF {
public static void main(String[] args) throws Exception{
PDDocument realDoc = PDDocument.load(new File("originaldocument.pdf"));
//the above is the document you want to watermark
//for all the pages, you can add overlay guide, indicating watermark the original pages with the watermark document.
HashMap<Integer, String> overlayGuide = new HashMap<Integer, String>();
for(int i=0; i<realDoc.getNumberOfPages(); i++){
overlayGuide.put(i+1, "watermark.pdf");
//watermark.pdf is the document which is a one page PDF with your watermark image in it.
//Notice here, you can skip pages from being watermarked.
}
Overlay overlay = new Overlay();
overlay.setInputPDF(realDoc);
overlay.setOutputFile("final.pdf");
overlay.setOverlayPosition(Overlay.Position.BACKGROUND);
overlay.overlay(overlayGuide);
}
}
如果你想使用新的包 org.apache.pdfbox.tools.OverlayPDF 进行覆盖，你可以这样做。 （感谢下面的海报）
String[] overlayArgs = {"C:/Examples/foreground.pdf", "C:/Examples/background.pdf", "C:/Examples/resulting.pdf"};
OverlayPDF.main(overlayArgs);
System.out.println("Overlay finished.");
旧答案效率低下，不推荐。
嗯，OP问如何在PDFBox中做到这一点，第一个答案看起来像是使用iText的示例。在 PDFBox 中创建水印非常简单。诀窍是，您应该有一个带有水印图像的空 PDF 文档。然后您所要做的就是将此水印文档覆盖在您要添加水印的文档上。
PDDocument watermarkDoc = PDDocument.load("watermark.pdf");
//Assuming your empty document with watermark image in it.
PDDocument realDoc = PDDocument.load("document-to-be-watermarked.pdf");
//Let's say this is your document that you want to watermark. For example sake, I am opening a new one, you would already have a reference to PDDocument if you are creating one
Overlay overlay = new Overlay();
overlay.overlay(realDoc,watermarkDoc);
watermarkDoc.save("document-now-watermarked.pdf");
警告：您应该确保两个文档中的页数匹配。否则，您最终得到的文档的页数将与页数最少的文档相匹配。您可以操作水印文档并复制页面以匹配您的文档。
希望这有帮助。！
刚刚编写了这段代码，使用 pdfbox 将（透明）图像（jpg、png、gif）添加到 pdf 页面：
/**
* Draw an image to the specified coordinates onto a single page. <br>
* Also scaled the image with the specified factor.
*
* @author Nick Russler
* @param document PDF document the image should be written to.
* @param pdfpage Page number of the page in which the image should be written to.
* @param x X coordinate on the page where the left bottom corner of the image should be located. Regard that 0 is the left bottom of the pdf page.
* @param y Y coordinate on the page where the left bottom corner of the image should be located.
* @param scale Factor used to resize the image.
* @param imageFilePath Filepath of the image that is written to the PDF.
* @throws IOException
*/
public static void addImageToPage(PDDocument document, int pdfpage, int x, int y, float scale, String imageFilePath) throws IOException {
// Convert the image to TYPE_4BYTE_ABGR so PDFBox won't throw exceptions (e.g. for transparent png's).
BufferedImage tmp_image = ImageIO.read(new File(imageFilePath));
BufferedImage image = new BufferedImage(tmp_image.getWidth(), tmp_image.getHeight(), BufferedImage.TYPE_4BYTE_ABGR);
image.createGraphics().drawRenderedImage(tmp_image, null);
PDXObjectImage ximage = new PDPixelMap(document, image);
PDPage page = (PDPage)document.getDocumentCatalog().getAllPages().get(pdfpage);
PDPageContentStream contentStream = new PDPageContentStream(document, page, true, true);
contentStream.drawXObject(ximage, x, y, ximage.getWidth()*scale, ximage.getHeight()*scale);
contentStream.close();
}
示例：
public static void main(String[] args) throws Exception {
String pdfFilePath = "C:/Users/Nick/Desktop/pdf-test.pdf";
String signatureImagePath = "C:/Users/Nick/Desktop/signature.png";
int page = 0;
PDDocument document = PDDocument.load(pdfFilePath);
addImageToPage(document, page, 0, 0, 0.5f, signatureImagePath);
document.save("C:/Users/Nick/Desktop/pdf-test-neu.pdf");
}
这对我有用jdk 1.7和bcmail-jdk16-140.jar，bcprov-jdk16-140.jar，commons-logging-1.1.3.jar，fontbox-1.8.3.jar，jempbox-1.8.3.jar和 pdfbox-1.8.3.jar。
@Androidman：添加到https://stackoverflow.com/a/9382212/7802973
PDFBox 的每个版本似乎都删除了许多方法。因此该代码无法在 PDFBox 2.0.7 上运行。
Overlay overlay = new Overlay();
overlay.setInputPDF(realDoc);
// ** The method setOutputFile(String) is undefined for the type Overlay **
overlay.setOutputFile("final.pdf")
相反，使用
void org.apache.pdfbox.pdmodel.PDDocument.save(String fileName)PDDocument realDoc = PDDocument.load(new File("originaldocument.pdf"));
//the above is the document you want to watermark
//for all the pages, you can add overlay guide, indicating watermark the original pages with the watermark document.
HashMap<Integer, String> overlayGuide = new HashMap<Integer, String>();
for(int i=0; i<realDoc.getNumberOfPages(); i++){
overlayGuide.put(i+1, "watermark.pdf");
//watermark.pdf is the document which is a one page PDF with your watermark image in it.
//Notice here, you can skip pages from being watermarked.
}
Overlay overlay = new Overlay();
overlay.setInputPDF(realDoc);
overlay.overlay(overlayGuide).save("final.pdf");
overlay.close();
编辑： 我现在使用
org.apache.pdfbox.tools.OverlayPDFString[] overlayArgs = {"C:/Examples/foreground.pdf", "C:/Examples/background.pdf", "C:/Examples/resulting.pdf"};
OverlayPDF.main(overlayArgs);
System.out.println("Overlay finished.");
由于我没有足够的声誉来添加评论，我认为在新答案中添加此内容是合适的。
util 包中还有另一个 Overlay 类，它可以让您免于创建与源文档页数相同的 pdf 然后进行覆盖。
要了解其用法，请查看 pdfbox 源代码，特别是 OverlayPDF 类。
这就是我如何使用 C# 中的 PdfBox 2.0.x 添加带有日期的文本水印。它将水印置于页面顶部的中心。
public static void AddWatermark(string fileName)
{
StringBuilder sb = new StringBuilder();
sb.Append("watermark_text ");
sb.Append(DateTime.Now.ToString());
string waterMarkText = sb.ToString();
PDDocument origDoc = PDDocument.load(new java.io.File(fileName));
PDPageTree allPages = origDoc.getPages();
PDFont font = PDType1Font.HELVETICA_BOLD;
for (int i = 0, len = allPages.getCount(); i < len; ++i)
{
PDPage pg = (PDPage)allPages.get(i);
AddWatermarkText(origDoc, pg, font, waterMarkText);
}
origDoc.save(fileName);
origDoc.close();
}
static void AddWatermarkText(PDDocument doc, PDPage page, PDFont font, string text)
{
using (PDPageContentStream cs = new PDPageContentStream(doc, page, PDPageContentStream.AppendMode.APPEND, true, true))
{
float fontHeight = 30;
float width = page.getMediaBox().getWidth();
float height = page.getMediaBox().getHeight();
float stringWidth = font.getStringWidth(text) / 1000 * fontHeight;
float x = (width / 2) - (stringWidth / 2);
float y = height - 25;
cs.setFont(font, fontHeight);
PDExtendedGraphicsState gs = new PDExtendedGraphicsState();
gs.setNonStrokingAlphaConstant(new java.lang.Float(0.2f));
gs.setStrokingAlphaConstant(new java.lang.Float(0.2f));
gs.setBlendMode(BlendMode.MULTIPLY);
gs.setLineWidth(new java.lang.Float(3f));
cs.setGraphicsStateParameters(gs);
cs.setNonStrokingColor(Color.red);
cs.setStrokingColor(Color.red);
cs.beginText();
cs.newLineAtOffset(x, y);
cs.showText(text);
cs.endText();
}
}
添加@Droidman的答案如果您使用版本2.0.21及以上，您可以直接覆盖在PDDocument上。示例代码如下。
PDDocument realDoc = pdfGenerator.getDocument();
HashMap<Integer, PDDocument> overlayGuide = new HashMap<>();
for (int i = 0; i < realDoc.getNumberOfPages(); i++) {
overlayGuide.put(i + 1, document);
}
Overlay overlay = new Overlay();
overlay.setInputPDF(realDoc);
overlay.setOverlayPosition(Overlay.Position.BACKGROUND);
overlay.overlayDocuments(overlayGuide);
查看这个 Java 库 WaterMarkIt 以添加可自定义水印。
WatermarkService.create()
.watermarkPDF(new File("path/to/file.pdf"))
.withImage(new File("path/to/watermark.png"))
.position(WatermarkPosition.TOP_LEFT)
.apply();
看看这个方法，它使用 PDFBOX 库在 pdf 源中添加水印图像
/**
* Coloca una imagen como marca de agua en un pdf en una posición especifica
*
* @param buffer
* flujo de bytes que contiene el pdf original
*
* @param imageFileName
* nombre del archivo de la imagen a colocar
*
* @param x
* posición x de la imagen en el pdf
*
* @param y
* posición y de la imagen en el pdf
*
* @param under
* determina si la marca se pone encima o por debajo de la factura
*
* @return flujo de bytes resultante que contiene el pdf modificado
*
* @throws IOException
* @throws DocumentException
*/
public static byte[] addWaterMarkImageToPDF(byte[] buffer,
String imageFileName, int x, int y, boolean under) throws IOException,
DocumentException {
logger.debug("Agregando marca de agua:"+imageFileName);
PdfReader reader = new PdfReader(buffer);
ByteArrayOutputStream arrayOutput = new ByteArrayOutputStream();
OutputStream output = new BufferedOutputStream(arrayOutput);
PdfStamper stamper = new PdfStamper(reader, output);
com.lowagie.text.Image img = com.lowagie.text.Image
.getInstance(imageFileName);
img.setAbsolutePosition(x, y);
img.scalePercent(SCALE_PER);
PdfContentByte pdfContent;
int total = reader.getNumberOfPages() + 1;
for (int i = 1; i < total; i++) {
pdfContent = (under)?stamper.getUnderContent(i):
stamper.getOverContent(i);
pdfContent.addImage(img);
}
stamper.close();
output.flush();
output.close();
return arrayOutput.toByteArray();
}