目录

1 Maven依赖

2 实现代码

2.1 createWaterMark

2.2  insertWaterRemark

3 调试代码

4 调试结果

 注：

1 Maven依赖

        
        
            com.alibaba
            easyexcel
            2.2.8
        
        
        
            cn.afterturn
            easypoi-base
            4.4.0
        
        
            org.apache.poi
            ooxml-schemas
            1.4
        

2 实现代码

2.1 createWaterMark

生成水印数据。

    
    public static byte[] createWaterMark(String content, int width, int height, java.awt.Color color, java.awt.Font font) throws IOException {
        // 获取bufferedImage对象
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 获取Graphics2d对象
        Graphics2D g2d = image.createGraphics();
        image = g2d.getDeviceConfiguration().createCompatibleImage(width, height, Transparency.TRANSLUCENT);
        g2d.dispose();
        g2d = image.createGraphics();
        //设置字体颜色
        g2d.setColor(color);
        g2d.setStroke(new BasicStroke(1));
        // 设置字体
        g2d.setFont(font);
        //设置倾斜度
        g2d.rotate(-0.5, (double) image.getWidth() / 2, (double) image.getHeight() / 2);
        FontRenderContext context = g2d.getFontRenderContext();
        Rectangle2D bounds = font.getStringBounds(content, context);
        double x = (width - bounds.getWidth()) / 2;
        double y = (height - bounds.getHeight()) / 2;
        double ascent = -bounds.getY();
        double baseY = y + ascent;
        // 写入水印文字原定高度过小，所以累计写水印，增加高度
        g2d.drawString(content, (int) x, (int) baseY);
        // 设置透明度
        g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER));
        // 释放对象
        g2d.dispose();
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        ImageIO.write(image, "png", os);
        return os.toByteArray();
    }

2.2  insertWaterRemark

插入水印，只支持07版Excel文档。

    
    public static void insertWaterRemark(XSSFSheet sheet, byte[] bytes) {
        //水印图片数据关联sheet对象
        XSSFWorkbook workbook = sheet.getWorkbook();
        int pictureIdx = workbook.addPicture(bytes, Workbook.PICTURE_TYPE_PNG);
        String relationId = sheet.addRelation(null, XSSFRelation.IMAGES, workbook.getAllPictures().get(pictureIdx))
                .getRelationship().getId();
        //将水印图片设置为sheet的背景颜色
        sheet.getCTWorksheet().addNewPicture().setId(relationId);
    }

3 调试代码

    
    @Test
    public void testInsertWaterMark() {
        try {
            XSSFWorkbook workbook = new XSSFWorkbook();
            XSSFSheet sheet = workbook.createSheet();
            File file = new File("D:/poi/testInsertWaterMark.xlsx");
            FileUtil.createNewFile(file);
            //生成水印
            byte[] waterMarkBytes = createWaterMark("旭东怪YYDS", 200, 150, new Color(255, 0, 0, 100)
                    , new Font("微软雅黑", Font.BOLD, 20));
            //插入水印
            insertWaterRemark(sheet, waterMarkBytes);
            workbook.write(new FileOutputStream(file));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

4 调试结果

 注：

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