POI导出Excel添加水印（XSSF）

/**
*原作者链接不记得了。。。。。。。
*导出的excel后缀是.xslx
*/


/**maven依赖

<!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.15</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.16</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml-schemas</artifactId>
    <version>3.14</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>ooxml-schemas</artifactId>
    <version>1.4</version>
</dependency>

*/

package com.poi.excel.water;

import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFRelation;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;

/**
 * @Author qixing.chen
 * @Date 2020/10/16 8:08 下午
 */
@RestController
@RequestMapping("/aa")
public class Watermark {

    @GetMapping("/cc")
    public String ex() {
        return "ok";
    }

    @GetMapping("/bb")
    public void export() {
        try {
            XSSFWorkbook workbook = new XSSFWorkbook();
            FileOutputStream out = new FileOutputStream("/Users/chen/Downloads/测试xlsx.xlsx");

            XSSFSheet sheet = workbook.createSheet("Sheet1");
            workbook.getSheet("Sheet1");

            //add picture data to this workbook.
//                FileInputStream is = new FileInputStream("/Users/Tony/Downloads/data_image.png");
//            byte[] bytes = IOUtils.toByteArray(is);


            BufferedImage image = FontImage.createWatermarkImage("测试水印","yyyy-MM-dd","#C5CBCF");
            // 导出到字节流B
            ByteArrayOutputStream os = new ByteArrayOutputStream();
            ImageIO.write(image, "png", os);

            int pictureIdx = workbook.addPicture(os.toByteArray(), Workbook.PICTURE_TYPE_PNG);
//            is.close();

            //add relation from sheet to the picture data
            String rID = sheet.addRelation(null, XSSFRelation.IMAGES, workbook.getAllPictures().get(pictureIdx)).getRelationship().getId();
           // String rid = sheet.addRelation(null,XSSFRelation.IMAGES,workbook.getAllPictures().get(pictureIdx))
            //set background picture to sheet
            sheet.getCTWorksheet().addNewPicture().setId(rID);

            workbook.write(out);

        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

package com.poi.excel.water;


import java.awt.*;
import java.awt.image.BufferedImage;

/**
 * @Author qixing.chen
 * @Date 2020/10/16 7:48 下午
 */
public class FontImage {




    public static BufferedImage createWatermarkImage(String text,String dateFormat,String color) {



        String[] textArray = text.split("\n");
        Font font = new Font("microsoft-yahei", Font.PLAIN, 20);
        Integer width = 600;
        Integer height = 200;

        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 背景透明 开始
        Graphics2D g = image.createGraphics();
        image = g.getDeviceConfiguration().createCompatibleImage(width, height, Transparency.TRANSLUCENT);
        g.dispose();
        // 背景透明 结束
        g = image.createGraphics();
        g.setColor(new Color(Integer.parseInt(color.substring(1), 16)));// 设定画笔颜色
        g.setFont(font);// 设置画笔字体
        g.shear(0.1, -0.26);// 设定倾斜度

//        设置字体平滑
        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

        int y = 50;
        for (int i = 0; i < textArray.length; i++) {
            g.drawString(textArray[i], 0, y);// 画出字符串
            y = y + font.getSize();
        }
        //g.drawString(DateUtils.getNowDateFormatCustom(watermark.getDateFormat()), 0, y);// 画出字符串
        g.drawString("2020-10-16", 0, y);// 画出字符串

        g.dispose();// 释放画笔
        return image;

    }

}



效果如下：