EasyExcel单元格合并策略

自定义策略

package cn.most.rsgzglxt.utils;

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.handler.CellWriteHandler;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteTableHolder;
import lombok.Data;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellType;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.util.CellRangeAddress;

import java.util.List;

/**
 * EasyExcel单元格合并策略
 */
@Data
public class ExcelFillCellMergeStrategy implements CellWriteHandler {
    
    /**
     * 合并字段的下标
     */
    private int[] mergeColumnIndex;
    
    /**
     * 合并几行
     */
    private int mergeRowIndex;

    public ExcelFillCellMergeStrategy() {
    }

    public ExcelFillCellMergeStrategy(int mergeRowIndex, int[] mergeColumnIndex) {
        this.mergeColumnIndex = mergeColumnIndex;
        this.mergeRowIndex = mergeRowIndex;
    }

    @Override
    public void beforeCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row,
                                 Head head, Integer integer, Integer integer1, Boolean aBoolean) {

    }

    @Override
    public void afterCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Cell cell,
                                Head head, Integer integer, Boolean aBoolean) {

    }


    public void afterCellDataConverted(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder,
                                       CellData cellData, Cell cell, Head head, Integer integer, Boolean aBoolean) {

    }

    @Override
    public void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder,
                                 List<WriteCellData<?>> list, Cell cell, Head head, Integer integer, Boolean aBoolean) {
        // 当前行
        int curRowIndex = cell.getRowIndex();
        // 当前列
        int curColIndex = cell.getColumnIndex();

        if (curRowIndex > mergeRowIndex) {
            for (int i = 0; i < mergeColumnIndex.length; i++) {
                if (curColIndex == mergeColumnIndex[i]) {
                    mergeWithPrevRow(writeSheetHolder, cell, curRowIndex, curColIndex);
                    break;
                }
            }
        }
    }

    private void mergeWithPrevRow(WriteSheetHolder writeSheetHolder, Cell cell, int curRowIndex, int curColIndex) {
        // 获取当前行的当前列的数据和上一行的当前列列数据，通过上一行数据是否相同进行合并
        Object curData = cell.getCellTypeEnum() == CellType.STRING ? cell.getStringCellValue() :
                cell.getNumericCellValue();
        Row preRow = cell.getSheet().getRow(curRowIndex - 1);
        if (preRow == null) {
            // 获取不到上一行的数据时,使用缓存sheet中的数据
            preRow = writeSheetHolder.getCachedSheet().getRow(curRowIndex - 1);
        }
        Cell preCell = preRow.getCell(curColIndex);
        Object preData = preCell.getCellTypeEnum() == CellType.STRING ? preCell.getStringCellValue() :
                preCell.getNumericCellValue();
        // 比较当前行的第一列的单元格与上一行是否相同，相同合并当前单元格与上一行
        if (curData.equals(preData)) {
            Sheet sheet = writeSheetHolder.getSheet();
            List<CellRangeAddress> mergeRegions = sheet.getMergedRegions();
            boolean isMerged = false;
            for (int i = 0; i < mergeRegions.size() && !isMerged; i++) {
                CellRangeAddress cellRangeAddr = mergeRegions.get(i);
                // 若上一个单元格已经被合并，则先移出原有的合并单元，再重新添加合并单元
                if (cellRangeAddr.isInRange(curRowIndex - 1, curColIndex)) {
                    sheet.removeMergedRegion(i);
                    cellRangeAddr.setLastRow(curRowIndex);
                    sheet.addMergedRegion(cellRangeAddr);
                    isMerged = true;
                }
            }
            // 若上一个单元格未被合并，则新增合并单元
            if (!isMerged) {
                CellRangeAddress cellRangeAddress = new CellRangeAddress(curRowIndex - 1, curRowIndex, curColIndex,
                        curColIndex);
                sheet.addMergedRegion(cellRangeAddress);
            }
        }
    }
}

Controller

String fileName = "xxxx.xlsx";
        try {
            List<XX> xxs = xxService.selectForExport();
            response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
            response.setContentType("application/vnd.ms-excel");
           
           // 对第几列执行合并策略
            int[] mergeColumeIndex = {0};
            // 从第几行开始执行合并策略
            int mergeRowIndex = 2;

            ExcelWriter excelWriter = EasyExcelFactory.write(response.getOutputStream())
                    .withTemplate(new ClassPathResource("moban/template.xlsx").getInputStream())
                    .registerWriteHandler(new ExcelFillCellMergeStrategy(mergeRowIndex, mergeColumeIndex))
                    .build();

            WriteSheet writeSheet = EasyExcel.writerSheet().build();

            excelWriter.fill(xxs, writeSheet);
            excelWriter.finish();
        } catch (IOException e) {
            e.printStackTrace();
        }

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