content: package com.fit2cloud.common.utils;
  
  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.collections4.CollectionUtils;
  import org.apache.poi.ss.usermodel.Cell;
  import org.apache.poi.ss.usermodel.Sheet;
  
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * 自适应列宽
   *
   * @author jiannengø
   **/
  public class CustomCellWriteWidthConfig 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 = this.dataLength(cellDataList, cell, isHead);
              // 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 数据集合
       * @param cell         单元格
       * @param isHead       是否头
       * @return {@link Integer }
       */
      private Integer dataLength(List<WriteCellData<?>> cellDataList, Cell cell, Boolean isHead) {
          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;
                      }
                      default -> {
                          return -1;
                      }
                  }
              }
          }
      }
  }
  