PDF合并和PDF加水印

1. maven

<dependency>
            <groupId>com.itextpdf</groupId>
            <artifactId>itextpdf</artifactId>
            <version>5.5.13</version>
        </dependency>
        <dependency>
            <groupId>com.itextpdf</groupId>
            <artifactId>itext-asian</artifactId>
            <version>5.2.0</version>
        </dependency>

/**
     * 水印
     * @param inputFilePath
     * @param outputFilePath
     * @param waterMarkContent
     */
    public static void pdfAddWaterMark(String inputFilePath, String outputFilePath, String waterMarkContent) {
        try {
            // 水印的高和宽
            int waterMarkHeight = 30;
            int watermarkWeight = 60;

            // 水印间隔距离
            int waterMarkInterval = 240;

            // 读取PDF文件流
            PdfReader pdfReader = new PdfReader(inputFilePath);

            // 创建PDF文件的模板，可以对模板的内容修改，重新生成新PDF文件
            PdfStamper pdfStamper = new PdfStamper(pdfReader, new FileOutputStream(outputFilePath));

            // 设置水印字体
            BaseFont baseFont = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H", BaseFont.EMBEDDED);

            // 设置PDF内容的Graphic State 图形状态
            PdfGState pdfGraPhicState = new PdfGState();
            // 填充透明度
            pdfGraPhicState.setFillOpacity(0.1f);
            // 轮廓不透明度
            pdfGraPhicState.setStrokeOpacity(0.2f);

            // PDF页数
            int pdfPageNum = pdfReader.getNumberOfPages() + 1;

            // PDF文件内容字节
            PdfContentByte pdfContent;

            // PDF页面矩形区域
            Rectangle pageRectangle;

            for (int i = 1; i < pdfPageNum; i++) {
                // 获取当前页面矩形区域
                pageRectangle = pdfReader.getPageSizeWithRotation(i);
                // 获取当前页内容，getOverContent表示之后会在页面内容的上方加水印
                pdfContent = pdfStamper.getOverContent(i);

                // 获取当前页内容，getOverContent表示之后会在页面内容的下方加水印
                // pdfContent = pdfStamper.getUnderContent(i);

                pdfContent.saveState();
                // 设置水印透明度
                pdfContent.setGState(pdfGraPhicState);

                // 开启写入文本
                pdfContent.beginText();
                // 设置字体
                pdfContent.setFontAndSize(baseFont, 20);

                // 在高度和宽度维度每隔waterMarkInterval距离添加一个水印
                for (int height = waterMarkHeight; height < pageRectangle.getHeight(); height = height + waterMarkInterval) {
                    for (int width = watermarkWeight; width < pageRectangle.getWidth() + watermarkWeight;
                         width = width + waterMarkInterval) {
                        // 添加水印文字并旋转30度角
                        pdfContent.showTextAligned(Element.ALIGN_LEFT, waterMarkContent, width - watermarkWeight,
                                height - waterMarkHeight, 30);
                    }
                }
                // 停止写入文本
                pdfContent.endText();
            }
            pdfStamper.close();
            pdfReader.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static void mergePDF(String[] inputFilePathList, String outputFilePath){
        try {
            Document document = new Document();
            PdfCopy copy = new PdfCopy(document,new FileOutputStream(outputFilePath));
            document.open();
            for (String s : inputFilePathList){
                PdfReader pdfReader = new PdfReader(s);
                for (int i =1 ; i<=pdfReader.getNumberOfPages();i++){
                    copy.addPage(copy.getImportedPage(pdfReader,i));
                }
                pdfReader.close();
            }
            document.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }