（Java）关于easyExcel合并单元格

        今天过客遇到一个需要合并单元格的业务，但是之前过客用的一直是easyExcel框架，所以这次也不想去使用其他的框架，今天就跟大家讲讲easyExcel怎么进行单元格的合并。

        首先使用easyExcel进行导出的实体类一样是依据之前那样写，之后在编写导出代码时候使用

.registerWriteHandler(new CustomMergeStrategy()) 方法，其中CustomMergeStrategy为自定义策略类。

 EasyExcel.write(outputStream)
                    .head(CombinationGoodsExcel.class)
                    .registerWriteHandler(new CustomMergeStrategy())

下面附上CustomMergeStrategy类代码：

package com.cfood.mdm.converter;

import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.metadata.data.WriteCellData;
import com.alibaba.excel.write.handler.CellWriteHandler;
import com.alibaba.excel.write.handler.context.CellWriteHandlerContext;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteTableHolder;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.util.List;

public class CustomMergeStrategy implements CellWriteHandler {
    @Override
    public void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, List> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
        if (isHead){
            //如果是表头不做处理
            return;
        }
        //如果当前是第一行不做处理
        if(relativeRowIndex==0){
            return;
        }

        //获取当前行下标，上一行下标，上一行对象，上一列对象
        Sheet sheet = cell.getSheet();
        int rowIndex = cell.getRowIndex();
        int rowIndexPrev=rowIndex- 1;
        Row row = sheet.getRow(rowIndexPrev);
        Cell cellPrev = row.getCell(cell.getColumnIndex());

        //得到当前单元格值和上一行单元格
       Object cellValue =cell.getCellType()== CellType.STRING?cell.getStringCellValue() : cell.getNumericCellValue();
       Object cellValuePrev =cellPrev.getCellType()==CellType.STRING?cellPrev.getStringCellValue():cellPrev.getNumericCellValue();

        System.out.println("cellValuePrev = " + cellValuePrev);
        System.out.println("cellValue = " + cellValue);
       //如果当前单元格和上一行单元格值相等就合并
        if (!cellValue.equals(cellValuePrev)) {
            return;
        }

        //获取已有策略
        List mergedRegions = sheet.getMergedRegions();

        boolean mergen=false;
        for (int i = 0; i < mergedRegions.size(); i++) {
            CellRangeAddress cellAddresses = mergedRegions.get(i);
            if(cellAddresses.isInRange(rowIndexPrev,cell.getColumnIndex())){
                sheet.removeMergedRegion(i);
                cellAddresses.setLastRow(rowIndex);
                sheet.addMergedRegion(cellAddresses);
                mergen=true;
                break;
            }

        }
        if (!mergen){
            CellRangeAddress cellAddresses = new CellRangeAddress(rowIndexPrev, rowIndex, cell.getColumnIndex(), cell.getColumnIndex());
            sheet.addMergedRegion(cellAddresses);
        }



    }


}

像这样就可以完成单元格的合并了。如图功效：