easyexcel实现导出添加文字水印
引入jar包
由于easyexcel没有引入ooxml-schemas包，所以需要额外添加。
<!-- easyexcel依赖 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>easyexcel</artifactId>
<version>2.2.6</version>
</dependency>
<!-- poi 添加水印 -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>ooxml-schemas</artifactId>
<version>1.4</version>
</dependency>
<!-- 使用了hutool的工具类 -->
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-all</artifactId>
</dependency>
新增水印配置类和WriteHandler
新增水印配置类
@Data
public class Watermark {
/**
* 水印内容
*/
private String content = "";
/**
* 画笔颜色. eg:#C5CBCF
*/
private String color = "#C5CBCF";
/**
* 字体颜色
*/
private Font font = new Font("microsoft-yahei", Font.PLAIN, 20);
/**
* 水印宽、高
*/
private int width = 300;
private int height = 100;
/**
* 倾斜度
*/
private double shear1 = 0.1;
private double shear2 = -0.26;
/**
* 字体的y轴位置
*/
private int yAxis = 50;
}
新增WriteHandler
注意：此方法只适用于XSSFWorkbook类，easyexcel默认使用的是SXSSFWorkbook类，在使用easyexcel导出时需要设置为inMemory模式，否则会抛出类型转换异常。
public class CustomWaterMarkHandler implements SheetWriteHandler {
private final Watermark watermark;
public CustomWaterMarkHandler(Watermark watermark) {
this.watermark = watermark;
}
@Override
public void beforeSheetCreate(WriteWorkbookHolder writeWorkbookHolder, WriteSheetHolder writeSheetHolder) {
}
@Override
public void afterSheetCreate(WriteWorkbookHolder writeWorkbookHolder, WriteSheetHolder writeSheetHolder) {
try {
BufferedImage bufferedImage = createWatermarkImage();
setWaterMarkToExcel((XSSFWorkbook) writeWorkbookHolder.getWorkbook(), bufferedImage);
} catch (Exception e) {
throw new RuntimeException("添加水印出错");
}
}
private BufferedImage createWatermarkImage() {
final Font font = watermark.getFont();
final int width = watermark.getWidth();
final int height = watermark.getHeight();
String[] textArray = watermark.getContent().split(",");
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();
// 设定画笔颜色
g.setColor(new Color(Integer.parseInt(watermark.getColor().substring(1), 16)));
// 设置画笔字体
g.setFont(font);
// 设定倾斜度
g.shear(watermark.getShear1(), watermark.getShear2());
// 设置字体平滑
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
int y = watermark.getYAxis();
for (String s : textArray) {
// 从画框的y轴开始画字符串.假设电脑屏幕中心为0，y轴为正数则在下方
g.drawString(s, 0, y);
y = y + font.getSize();
}
// 释放画笔
g.dispose();
return image;
}
private void setWaterMarkToExcel(XSSFWorkbook workbook, BufferedImage bfi) {
//将图片添加到工作簿
int pictureIdx = workbook.addPicture(ImgUtil.toBytes(bfi, ImgUtil.IMAGE_TYPE_PNG), Workbook.PICTURE_TYPE_PNG);
//建立 sheet 和 图片 的关联关系
XSSFPictureData xssfPictureData = workbook.getAllPictures().get(pictureIdx);
for (int i = 0; i < workbook.getNumberOfSheets(); i++) {
XSSFSheet xssfSheet = workbook.getSheetAt(i);
PackagePartName packagePartName = xssfPictureData.getPackagePart().getPartName();
PackageRelationship packageRelationship = xssfSheet.getPackagePart()
.addRelationship(packagePartName, TargetMode.INTERNAL, XSSFRelation.IMAGES.getRelation(), null);
//添加水印到工作表
xssfSheet.getCTWorksheet().addNewPicture().setId(packageRelationship.getId());
}
}
}
测试
//水印配置
Watermark watermark = new Watermark();
watermark.setContent("测试文字水印");
watermark.setWidth(500);
watermark.setHeight(200);
watermark.setYAxis(200);
//导出
EasyExcel.write(outputStream, Test.class)
.inMemory(true)
.sheet("sheet1")
.registerWriteHandler(new CustomWaterMarkHandler(watermark))
.doWrite(Collections.singletonList(new Test()));