给pdf加水印的方法

 1

.依赖

        
            com.itextpdf
            itext-asian
            5.2.0
        

2.水印图片在项目中的位置

 

3.代码实现 

import com.itextpdf.text.Image;
import com.itextpdf.text.pdf.PdfContentByte;
import com.itextpdf.text.pdf.PdfGState;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfStamper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.FileOutputStream;
import java.io.IOException;

/***
 * PDF水印工具类
 */
public class PDFWatermarkUtil {
    private static final Logger LOGGER = LoggerFactory.getLogger(PDFWatermarkUtil.class);

    /***
     * 执行添加图片水印
     * @param inputFilePath    原始文件
     * @param outputFilePath   添加水印文件
     * @param watermarkPath    水印图片
     */
    public static boolean addWatermark(String inputFilePath, String outputFilePath, String watermarkPath) {
        FileOutputStream fileOutputStream = null;
        try {
            // 待加水印的文件
            PdfReader pdfReader = new PdfReader(inputFilePath);
            fileOutputStream = new FileOutputStream(outputFilePath);
            // 加完水印的文件
            PdfStamper pdfStamper = new PdfStamper(pdfReader, fileOutputStream);
            int total = pdfReader.getNumberOfPages() + 1;
            //设置透明度
            PdfGState gs = new PdfGState();
            gs.setFillOpacity(0.3f);

            Image image = Image.getInstance(watermarkPath);

            //循环对每页插入水印
            for (int i = 1; i < total; i++) {
                PdfContentByte pdfContentByte = pdfStamper.getOverContent(i);
                pdfContentByte.setGState(gs);
                image.setAbsolutePosition(0, 0);
                pdfContentByte.addImage(image);
            }
            pdfStamper.close();
            pdfReader.close();
        } catch (Exception e) {
            LOGGER.error("executeWatermark exception", e);
            return false;
        }finally {
            try {
                if(fileOutputStream != null){
                    fileOutputStream.flush();
                    fileOutputStream.close();
                }
            } catch (IOException e) {
                LOGGER.error("fileOutputStream close exception", e);
            }
        }

        return true;
    }
}