实现ExcelWriteHandlerExtendApi接口从而实现对Excel增加复杂功能的操作。如添加水印。具体实现请自行百度
/**
* 根据上下文判断是否执行
*
* @param context Excel定义上下文
* @return 是否执行该扩展
*/
boolean match(ExcelDefinitionContext context);
/**
* 构建出一个WriteWorkbook对象，即一个工作簿对象，对应的是一个Excel文件；
*
* @param builder 可用于设置inMemory=true实现复杂功能（如添加水印）
*/
default void extendBuilder(ExcelWriterBuilder builder) {
}例：Excel添加水印
本例参考文章：Java使用EasyExcel导出添加水印
实现ExcelWriteHandlerExtendApi接口，并添加@Component注解
添加依赖包
<!-- eaysexcel -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>easyexcel</artifactId>
<version>3.3.2</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>
<version>5.8.20</version>
</dependency>package pro.shushi.pamirs.top.core.temp;
import cn.hutool.core.img.ImgUtil;
import com.alibaba.excel.write.builder.ExcelWriterBuilder;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteWorkbookHolder;
import org.apache.poi.openxml4j.opc.PackagePartName;
import org.apache.poi.openxml4j.opc.PackageRelationship;
import org.apache.poi.openxml4j.opc.TargetMode;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFPictureData;
import org.apache.poi.xssf.usermodel.XSSFRelation;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.stereotype.Component;
import pro.shushi.pamirs.file.api.context.ExcelDefinitionContext;
import pro.shushi.pamirs.file.api.easyexcel.ExcelWriteHandlerExtendApi;
import java.awt.*;
import java.awt.image.BufferedImage;
@Component
public class CustomWaterMarkHandler implements ExcelWriteHandlerExtendApi {
private final WaterMark watermark;
public CustomWaterMarkHandler() {
this.watermark = new WaterMark().setContent("ABC");
}
@Override
public void extendBuilder(ExcelWriterBuilder builder) {
builder.inMemory(true);
}
@Override
public boolean match(ExcelDefinitionContext context) {
return DemoTemplate.TEMPLATE_NAME.equals(context.getName());
}
@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",e);
}
}
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());
}
}
}
水印配置类
/**
* 水印配置类
*/
@Data
@Component
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;
}Oinone社区 作者：yexiu原创文章，如若转载，请注明出处：https://doc.oinone.top/dai-ma-shi-jian/17119.html
访问Oinone官网:https://www.oinone.top获取数式Oinone低代码应用平台体验
