EasyExcel 自定义宽高

package com.cloud.module.management.common.handler;

import cn.hutool.core.util.ObjectUtil;
import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.metadata.data.CellData;
import com.alibaba.excel.metadata.data.WriteCellData;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.style.column.AbstractColumnWidthStyleStrategy;
import org.apache.commons.collections.CollectionUtils;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Sheet;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


public class CustomCellWriteWidthHandle extends AbstractColumnWidthStyleStrategy {

    private final Map<Integer, Map<Integer, Integer>> CACHE = new HashMap<>();
    @Override
    protected void setColumnWidth(WriteSheetHolder writeSheetHolder, List<WriteCellData<?>> cellDataList, Cell cell, Head head, Integer integer, Boolean isHead) {
        boolean needSetWidth = isHead || !CollectionUtils.isEmpty(cellDataList);
        if (needSetWidth) {
            Map<Integer, Integer> maxColumnWidthMap = CACHE.computeIfAbsent(writeSheetHolder.getSheetNo(), k -> new HashMap<>());

            Integer columnWidth = null;
            try {
                columnWidth = this.dataLength(cellDataList, cell, isHead);
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            // 单元格文本长度大于60换行
            if (columnWidth >= 0) {
                if (columnWidth > 60) {
                    columnWidth = 60;
                }
                Integer maxColumnWidth = maxColumnWidthMap.get(cell.getColumnIndex());
                if (maxColumnWidth == null || columnWidth > maxColumnWidth) {
                    maxColumnWidthMap.put(cell.getColumnIndex(), columnWidth);
                    Sheet sheet = writeSheetHolder.getSheet();
                    sheet.setColumnWidth(cell.getColumnIndex(), columnWidth * 256);
                }
            }
        }
    }
    /**
     * 计算长度
     * @param cellDataList
     * @param cell
     * @param isHead
     * @return
     */
    private Integer dataLength(List<WriteCellData<?>> cellDataList, Cell cell, Boolean isHead) throws IOException {
        if (isHead) {
            return cell.getStringCellValue().getBytes().length;
        } else {
            CellData<?> cellData = cellDataList.get(0);
            CellDataTypeEnum type = cellData.getType();
            if (type == null) {
                return -1;
            } else {
                switch (type) {
                    case STRING:
                        // 换行符（数据需要提前解析好）
                        int index = cellData.getStringValue().indexOf("\n");
                        return index != -1 ?
                                cellData.getStringValue().substring(0, index).getBytes().length + 1 : cellData.getStringValue().getBytes().length + 1;
                    case BOOLEAN:
                        return cellData.getBooleanValue().toString().getBytes().length;
                    case NUMBER:
                        return cellData.getNumberValue().toString().getBytes().length;
                    // 如果是图片返回图片的宽度，并设置row的高度为图片的高度
                    case EMPTY:
                        if (ObjectUtil.isNotEmpty(cellDataList)  && ObjectUtil.isNotEmpty(cellDataList.get(0))) {
                            BufferedImage bufferedImage = ImageIO.read(new ByteArrayInputStream(cellDataList.get(0).getImageDataList().get(0).getImage()));
                            int originalWidth = bufferedImage.getWidth();
                            int originalHeight = bufferedImage.getHeight();

                            // 计算与210的宽度的比例
                            double ratio = (double) 210 / originalWidth;
                            int newWidth = 210; // 设置新宽度为210
                            int newHeight = (int) (originalHeight * ratio);

                            // 将像素转换为磅以设置Excel行高
                            double heightInPoints = newHeight * 0.75;
                            cell.getRow().setHeightInPoints((float) heightInPoints);

                            // 将像素转换为Excel中的宽度单位
                            double charWidth = 7.0; // 默认的Excel字体中标准字符的大致宽度
                            double estimatedChars = newWidth / charWidth;
                            return (int) estimatedChars; // 以Excel单位返回调整后的宽度
                        }
                        return -1;
                    default:
                        return -1;
                }
            }
        }
    }
}

　　

       // 导出 Excel 文件
            EasyExcel.write(response.getOutputStream(), this.entityClass)
                    .sheet(dto.getSheetName())
                    .includeColumnFiledNames(dto.getColumnList())
                    .registerWriteHandler(new CustomCellWriteWidthHandle()) /*自适应列宽*/
                    .registerWriteHandler(seedDemandCellWriteHandler)
                    .doWrite(writeList);