EasyExcel 动态合并列

package com.ksec.eicp.crmc.listener.easyexcel;

import cn.hutool.core.util.StrUtil;
import com.alibaba.excel.write.handler.AbstractRowWriteHandler;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteTableHolder;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.util.CellRangeAddress;

/*

• 自定义合并列策略
• @version V1.0
• @author zhang ji

• @ date 2020-09-15 9:29
  **/
  @Getter
  @Setter
  @ToString
  public class DefaultMergeRowStrategy extends AbstractRowWriteHandler {

  /**

  • 合并比对起始行值
    */
    private String defaultValue;
    /**
  • 合并目标列索引
    */
    private Integer cellIndex;
    /**
  • 数据开始行索引
    */
    private Integer dataBeginRowIndex;
    /**
  • 当前导出数据长度
    */
    private Integer dataLength;
    /**
  • 开始行索引
    */
    private Integer mergeBeginRowIndex;

  public DefaultMergeRowStrategy(String defaultValue, Integer cellIndex, Integer dataBeginRowIndex, Integer dataLength) {
  this.defaultValue = defaultValue;
  this.cellIndex = cellIndex;
  this.dataBeginRowIndex = dataBeginRowIndex;
  this.dataLength = dataLength;
  }

  @Override
  public void afterRowDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row,
  Integer relativeRowIndex, Boolean isHead) {
  if (isHead) {
  return;
  }

  String cellValueStr = StrUtil.isNotBlank(row.getCell(cellIndex).getStringCellValue())?
          row.getCell(cellIndex).getStringCellValue():"";
  
  //遇到不一致的值，前面进行合并
  if(!cellValueStr.equals(defaultValue)) {
      this.mergeRow(writeSheetHolder.getSheet(),
              null != this.mergeBeginRowIndex?this.mergeBeginRowIndex:this.dataBeginRowIndex,
              row.getRowNum() - 1,
              this.cellIndex,
              this.cellIndex);
      this.mergeBeginRowIndex = row.getRowNum() + (this.dataLength == relativeRowIndex + 1?1:0);
      this.defaultValue = cellValueStr;
  } else {
  
      //判断是否是最后一组记录，最后一组记录不会进入上方判断逻辑，故需单独处理合并
      if(this.dataLength == relativeRowIndex + 1) {
          //一条记录不进行合并
          if(((null != this.mergeBeginRowIndex?this.mergeBeginRowIndex:this.dataBeginRowIndex)) != row.getRowNum()) {
              this.mergeRow(writeSheetHolder.getSheet(),
                      null != this.mergeBeginRowIndex?this.mergeBeginRowIndex:this.dataBeginRowIndex,
                      row.getRowNum(),
                      this.cellIndex,
                      this.cellIndex);
          }
  
          this.mergeBeginRowIndex = row.getRowNum() + 1;
          this.defaultValue = "";
      }
  
  }

  }

  private void mergeRow(Sheet sheet, int firstRow, int lastRow, int firstCol, int lastCol) {
  CellRangeAddress cellRangeAddress = new CellRangeAddress(firstRow, lastRow, firstCol, lastCol);
  sheet.addMergedRegionUnsafe(cellRangeAddress);
  }

}