A Tool Class in Java to Implement PDF Watermarking

preface

Recently, the company has made a request to add a watermark to the user uploaded files Word and pdf. For doc and docx files, first convert Word to pdf and then add a watermark. For pdf files, add a watermark directly.

Before Word to pdf, the service has realized direct code reuse, and pdf can be directly used by adding watermarks through itextpdf. This article is just a note.

Procedure

1、 Import Dependencies

 <!--  Operation on PDF file --> <dependency> <groupId>com.itextpdf</groupId> <artifactId>itextpdf</artifactId> <version>5.5.13.1</version> </dependency> <!--  PDF file font prevents Chinese garbled code --> <dependency> <groupId>com.itextpdf</groupId> <artifactId>itext-asian</artifactId> <version>5.2.0</version> </dependency>

2、 Tool code

 import com.itextpdf.text.Element; import com.itextpdf.text.pdf.*; import org.apache.commons.io.IOUtils; import java.io.FileInputStream; import java.io.OutputStream; import java.nio.file.Files; import java.nio.file.Paths; import java.util.Optional; /** * WatermarkUtils *PDF Add Watermark Tool Class * * @author Lcry */ public class WaterMarkUtils { Public static final String DEFAULT_WATERMARK_TEXT="Top Secret Information"; /** *Pdf Add Watermark * *@ param waterMarkText Watermark text * @param pdfFileBytes   pdf *@ param outputFilePath output stream */ public static void addWaterMark(String waterMarkText, byte[] pdfFileBytes, OutputStream outputFilePath) { try { //Original PDF file PdfReader reader = new PdfReader(pdfFileBytes); //Exported PDF file content PdfStamper stamper = new PdfStamper(reader, outputFilePath); //Font comes from the itext asian jar package BaseFont baseFont = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H", true); PdfGState gs = new PdfGState(); //Set Transparency gs.setFillOpacity(0.2f); gs.setStrokeOpacity(0.3f); int totalPage = reader.getNumberOfPages() + 1; for (int i = 1;  i < totalPage; i++) { //Content upper layer PdfContentByte content = stamper.getOverContent(i); content.beginText(); //Font Add Transparency content.setGState(gs); //Add font size, etc content.setFontAndSize(baseFont, 170); //Add Range content.showTextAligned(Element. ALIGN_BOTTOM, Optional.ofNullable(waterMarkText).orElse(""), 100, 100, 45); content.endText(); } //Close stamper.close(); reader.close(); } catch (Exception e) { e.printStackTrace(); } } }

3、 Test

 public static void main(String[] args) throws Exception { FileInputStream fileInputStream = new FileInputStream("C:\\Users\\lcry\\Downloads\\2021sj.pdf"); AddWaterMark ("Confidential Information", IOUtils. toByteArray (fileInputStream), Files. newOutputStream (Paths. get ("C:   Users   lcry   Downloads   2021sj mark. pdf")); }

Effect Preview

Effect without watermark:

Effect after water printing:

Reference article

The java implementation adds picture watermark to the PDF file, and the java implementation adds text watermark to the PDF file

Add text watermark to java pdf (very professional)

The method of adding watermark to pdf

Java project uses itextpdf to add watermark to pdf file