引入所需jar包
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.11</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.11</version>
</dependency>
添加水印工具类
import org.apache.poi.ss.usermodel.*;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
public class ExcelWaterRemarkUtils {
/*
* 为Excel打上水印工具函数 请自行确保参数值,以保证水印图片之间不会覆盖。 在计算水印的位置的时候,并没有考虑到单元格合并的情况,请注意
*
* @param wb
* Excel Workbook
* @param sheet
* 需要打水印的Excel
* @param waterRemarkPath
* 水印地址,classPath,目前只支持png格式的图片,
* 因为非png格式的图片打到Excel上后可能会有图片变红的问题,且不容易做出透明效果。
* 同时请注意传入的地址格式,应该为类似:"\\excelTemplate\\test.png"
* @param startXCol
* 水印起始列
* @param startYRow
* 水印起始行
* @param betweenXCol
* 水印横向之间间隔多少列
* @param betweenYRow
* 水印纵向之间间隔多少行
* @param XCount
* 横向共有水印多少个
* @param YCount
* 纵向共有水印多少个
* @param waterRemarkWidth
* 水印图片宽度为多少列
* @param waterRemarkHeight
* 水印图片高度为多少行
* @throws IOException
*/
public static void putWaterRemarkToExcel(Workbook wb, Sheet sheet, String waterRemarkPath, int startXCol,
int startYRow, int betweenXCol, int betweenYRow, int XCount, int YCount, int waterRemarkWidth,
int waterRemarkHeight) throws IOException {
// 校验传入的水印图片格式
if (!waterRemarkPath.endsWith("png") && !waterRemarkPath.endsWith("PNG")) {
throw new RuntimeException("向Excel上面打印水印,目前支持png格式的图片。");
}
// 加载图片
ByteArrayOutputStream byteArrayOut = new ByteArrayOutputStream();
InputStream imageIn = new FileInputStream(waterRemarkPath);
//InputStream imageIn = Thread.currentThread().getContextClassLoader().getResourceAsStream(waterRemarkPath);
if (null == imageIn || imageIn.available() < 1) {
throw new RuntimeException("向Excel上面打印水印,读取水印图片失败(1)。");
}
BufferedImage bufferImg = ImageIO.read(imageIn);
if (null == bufferImg) {
throw new RuntimeException("向Excel上面打印水印,读取水印图片失败(2)。");
}
ImageIO.write(bufferImg, "png", byteArrayOut);
// 开始打水印
Drawing drawing = sheet.createDrawingPatriarch();
// 按照共需打印多少行水印进行循环
for (int yCount = 0; yCount < YCount; yCount++) {
// 按照每行需要打印多少个水印进行循环
for (int xCount = 0; xCount < XCount; xCount++) {
// 创建水印图片位置
int xIndexInteger = startXCol + (xCount * waterRemarkWidth) + (xCount * betweenXCol);
int yIndexInteger = startYRow + (yCount * waterRemarkHeight) + (yCount * betweenYRow);
/*
* 参数定义: 第一个参数是(x轴的开始节点); 第二个参数是(是y轴的开始节点); 第三个参数是(是x轴的结束节点);
* 第四个参数是(是y轴的结束节点); 第五个参数是(是从Excel的第几列开始插入图片,从0开始计数);
* 第六个参数是(是从excel的第几行开始插入图片,从0开始计数); 第七个参数是(图片宽度,共多少列);
* 第8个参数是(图片高度,共多少行);
*/
ClientAnchor anchor = drawing.createAnchor(0, 0, 0, 0, xIndexInteger,
yIndexInteger, xIndexInteger + waterRemarkWidth, yIndexInteger + waterRemarkHeight);
Picture pic = drawing.createPicture(anchor,
wb.addPicture(byteArrayOut.toByteArray(), Workbook.PICTURE_TYPE_PNG));
pic.resize();
}
}
}
}
根据文字生成水印图片
public static void createWaterMark(String content, String path) throws IOException {
Integer width = 300;
Integer height = 200;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);// 获取bufferedImage对象
String fontType = "宋体";
Integer fontStyle = Font.PLAIN;
Integer fontSize = 50;
Font font = new Font(fontType, fontStyle, fontSize);
Graphics2D g2d = image.createGraphics(); // 获取Graphics2d对象
image = g2d.getDeviceConfiguration().createCompatibleImage(width, height, Transparency.TRANSLUCENT);
g2d.dispose();
g2d = image.createGraphics();
g2d.setColor(new Color(0, 0, 0, 80)); //设置字体颜色和透明度
g2d.setStroke(new BasicStroke(1)); // 设置字体
g2d.setFont(font); // 设置字体类型 加粗 大小
g2d.rotate(Math.toRadians(-10), (double) image.getWidth() / 2, (double) image.getHeight() / 2);//设置倾斜度
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();
ImageIO.write(image, "png", new File(path));
}
public static void main(String[] args) throws IOException {
//读取excel文件
Workbook wb = new XSSFWorkbook(new FileInputStream("E:\\test.xlsx"));
//设置水印图片路径
String imgPath = "E:\\水印.png";
ImageUtils.createWaterMark("文字水印效果", imgPath);
//获取excel sheet个数
int sheets = wb.getNumberOfSheets();
//循环sheet给每个sheet添加水印
for (int i = 0; i < sheets; i++) {
Sheet sheet = wb.getSheetAt(i);
//excel加密只读
//sheet.protectSheet(UUID.randomUUID().toString());
//获取excel实际所占行
int row = sheet.getFirstRowNum() + sheet.getLastRowNum();
//获取excel实际所占列
int cell = sheet.getRow(sheet.getFirstRowNum()).getLastCellNum() + 1;
//根据行与列计算实际所需多少水印
ExcelWaterRemarkUtils.putWaterRemarkToExcel(wb, sheet, imgPath, 0, 0, 5, 5, cell / 5 + 1, row / 5 + 1, 0, 0);
}
ByteArrayOutputStream os = new ByteArrayOutputStream();
try {
wb.write(os);
} catch (IOException e) {
e.printStackTrace();
}
wb.close();
byte[] content = os.toByteArray();
// Excel文件生成后存储的位置。
File file1 = new File("E:\\watermark.xlsx");
OutputStream fos = null;
try {
fos = new FileOutputStream(file1);
fos.write(content);
os.close();
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}
最终效果