1、合并单元格处理器

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.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteTableHolder;
import lombok.extern.slf4j.Slf4j;
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 org.springframework.util.ObjectUtils;

import java.util.List;

/**
 * 合并处理器
 */
@Slf4j
public class ExcelFillCellLineMergeHandler implements CellWriteHandler {
    private int[] mergeColumnIndex;
    private int mergeRowIndex;

    public ExcelFillCellLineMergeHandler() {
    }

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

    @Override
    public void beforeCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row, Head head, Integer columnIndex, Integer relativeRowIndex, Boolean isHead) {

    }
    @Override
    public void afterCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {

    }

    @Override
    public void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, List<WriteCellData<?>> list, Cell cell, Head head, Integer integer, Boolean aBoolean) {
        int curRowIndex = cell.getRowIndex(); //当前单元格的行数
        int curColIndex = cell.getColumnIndex(); // 当前单元格的列数
        if (curRowIndex > mergeRowIndex) {
            for (int i = 0; i < mergeColumnIndex.length; i++) {
                if (curColIndex == mergeColumnIndex[i]) {
                    //单元格数据处理
                    mergeWithPrevRow(writeSheetHolder, cell, curRowIndex, curColIndex);
                    break;
                }
            }
        }
    }
    /**
     * @description 当前单元格向上合并
     * cell             当前单元格
     * curRowIndex      当前行
     * curColIndex      当前列
     * @params [writeSheetHolder, cell, curRowIndex, curColIndex]
     * @return void
     * @throws
     */
    private void mergeWithPrevRow(WriteSheetHolder writeSheetHolder, Cell cell, int curRowIndex, int curColIndex) {
        //当前单元格中数据
        Object curData = cell.getCellType() == CellType.STRING ? cell.getStringCellValue() : cell.getNumericCellValue();
        Object leftCellData = "";
        Object preLeftCellData = "";
        if (curRowIndex >1 && curColIndex >1) {
            Cell leftCell = cell.getSheet().getRow(curRowIndex).getCell(1);
            leftCellData = leftCell.getCellType() == CellType.STRING ? leftCell.getStringCellValue() : leftCell.getNumericCellValue();
        }
        
        //获取当前单元格的上面一个单元格
        Cell preCell = cell.getSheet().getRow(curRowIndex - 1).getCell(curColIndex);
        if (curRowIndex >1 && curColIndex >1) {
            Cell preLeftCell = cell.getSheet().getRow(curRowIndex - 1).getCell(1);
            preLeftCellData = preLeftCell.getCellType() == CellType.STRING ? preLeftCell.getStringCellValue() : preLeftCell.getNumericCellValue();
        }

        //获取当前单元格的上面一个单元格中的数据
        Object preData = preCell.getCellType() == CellType.STRING ? preCell.getStringCellValue() : preCell.getNumericCellValue();
        // 将当前单元格数据与上一个单元格数据比较
        if (leftCellData.equals(preLeftCellData) && preData.equals(curData)) {
            //获取当前sheet页
            Sheet sheet = writeSheetHolder.getSheet();
            //得到所有的合并单元格
            List<CellRangeAddress> mergeRegions = sheet.getMergedRegions();
            //是否合并
            boolean isMerged = false;
            for (int i = 0; i < mergeRegions.size() && !isMerged; i++) {
                //CellRangeAddress POI合并单元格
                //CellRangeAddress(int firstRow, int lastRow, int firstCol, int lastCol)
                //例子：CellRangeAddress（2, 6000, 3, 3）；
                //第2行起 第6000行终止 第3列开始 第3列结束。
                CellRangeAddress cellRangeAddr = mergeRegions.get(i);
                // cellRangeAddr.isInRange(int rowInd, int colInd)确定给定坐标是否在此范围的范围内。
                // 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);
            }
        }
    }
}

 2、单元格样式

import com.alibaba.excel.write.metadata.style.WriteCellStyle;
import com.alibaba.excel.write.metadata.style.WriteFont;
import org.apache.poi.ss.usermodel.*;
 
public class StyleUtils {
 
    /**
     * 标题样式
     * @return
     */
    public static WriteCellStyle getHeadStyle(){
        // 头的策略
        WriteCellStyle headWriteCellStyle = new WriteCellStyle();
        // 背景颜色
//        headWriteCellStyle.setFillForegroundColor(IndexedColors.LIGHT_TURQUOISE1.getIndex());
//        headWriteCellStyle.setFillPatternType(FillPatternType.SOLID_FOREGROUND);
 
        // 字体
        WriteFont headWriteFont = new WriteFont();
        headWriteFont.setFontName("宋体");//设置字体名字
        headWriteFont.setFontHeightInPoints((short)14);//设置字体大小
        headWriteFont.setBold(true);//字体加粗
        headWriteCellStyle.setWriteFont(headWriteFont); //在样式用应用设置的字体;
 
        // 样式
        headWriteCellStyle.setBorderBottom(BorderStyle.THIN);//设置底边框;
        headWriteCellStyle.setBottomBorderColor((short) 0);//设置底边框颜色;
        headWriteCellStyle.setBorderLeft(BorderStyle.THIN);  //设置左边框;
        headWriteCellStyle.setLeftBorderColor((short) 0);//设置左边框颜色;
        headWriteCellStyle.setBorderRight(BorderStyle.THIN);//设置右边框;
        headWriteCellStyle.setRightBorderColor((short) 0);//设置右边框颜色;
        headWriteCellStyle.setBorderTop(BorderStyle.THIN);//设置顶边框;
        headWriteCellStyle.setTopBorderColor((short) 0); //设置顶边框颜色;
 
        headWriteCellStyle.setWrapped(true);  //设置自动换行;
 
        headWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);//设置水平对齐的样式为居中对齐;
        headWriteCellStyle.setVerticalAlignment(VerticalAlignment.CENTER);  //设置垂直对齐的样式为居中对齐;
        headWriteCellStyle.setShrinkToFit(true);//设置文本收缩至合适
 
        return headWriteCellStyle;
    }
 
 
    /**
     * 内容样式
     * @return
     */
    public static WriteCellStyle getContentStyle(){
        // 内容的策略
        WriteCellStyle contentWriteCellStyle = new WriteCellStyle();
 
        // 背景绿色
        // 这里需要指定 FillPatternType 为FillPatternType.SOLID_FOREGROUND 不然无法显示背景颜色.头默认了 FillPatternType所以可以不指定
//        contentWriteCellStyle.setFillForegroundColor(IndexedColors.PALE_BLUE.getIndex());
//        contentWriteCellStyle.setFillPatternType(FillPatternType.SOLID_FOREGROUND);
 
        // 设置字体
        WriteFont contentWriteFont = new WriteFont();
        contentWriteFont.setFontHeightInPoints((short) 12);//设置字体大小
        contentWriteFont.setFontName("宋体"); //设置字体名字
        contentWriteCellStyle.setWriteFont(contentWriteFont);//在样式用应用设置的字体;
 
        //设置样式;
        contentWriteCellStyle.setBorderBottom(BorderStyle.THIN);//设置底边框;
        contentWriteCellStyle.setBottomBorderColor((short) 0);//设置底边框颜色;
        contentWriteCellStyle.setBorderLeft(BorderStyle.THIN);  //设置左边框;
        contentWriteCellStyle.setLeftBorderColor((short) 0);//设置左边框颜色;
        contentWriteCellStyle.setBorderRight(BorderStyle.THIN);//设置右边框;
        contentWriteCellStyle.setRightBorderColor((short) 0);//设置右边框颜色;
        contentWriteCellStyle.setBorderTop(BorderStyle.THIN);//设置顶边框;
        contentWriteCellStyle.setTopBorderColor((short) 0); ///设置顶边框颜色;
 
        contentWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);// 水平居中
        contentWriteCellStyle.setVerticalAlignment(VerticalAlignment.CENTER);// 垂直居中
        contentWriteCellStyle.setWrapped(true); //设置自动换行;
 
//        contentWriteCellStyle.setShrinkToFit(true);//设置文本收缩至合适
 
        return contentWriteCellStyle;
    }
 
}

import java.util.List;
 
import com.alibaba.excel.metadata.data.WriteCellData;
import com.alibaba.excel.util.ListUtils;
import com.alibaba.excel.write.handler.context.CellWriteHandlerContext;
import com.alibaba.excel.write.metadata.style.WriteCellStyle;

import com.alibaba.excel.write.style.AbstractCellStyleStrategy;
import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.Setter;
import org.apache.commons.collections4.CollectionUtils;
 

@Getter
@Setter
@EqualsAndHashCode
public class HorizontalCellStyleStrategy extends AbstractCellStyleStrategy {
 
    private WriteCellStyle headWriteCellStyle;
    private List<WriteCellStyle> contentWriteCellStyleList;
 
    public HorizontalCellStyleStrategy() {
    }
 
    public HorizontalCellStyleStrategy(WriteCellStyle headWriteCellStyle,
        List<WriteCellStyle> contentWriteCellStyleList) {
        this.headWriteCellStyle = headWriteCellStyle;
        this.contentWriteCellStyleList = contentWriteCellStyleList;
    }
 
    public HorizontalCellStyleStrategy(WriteCellStyle headWriteCellStyle, WriteCellStyle contentWriteCellStyle) {
        this.headWriteCellStyle = headWriteCellStyle;
        if (contentWriteCellStyle != null) {
            this.contentWriteCellStyleList = ListUtils.newArrayList(contentWriteCellStyle);
        }
    }
 
    @Override
    protected void setHeadCellStyle(CellWriteHandlerContext context) {
        if (stopProcessing(context) || headWriteCellStyle == null) {
            return;
        }
        WriteCellData<?> cellData = context.getFirstCellData();
        WriteCellStyle.merge(headWriteCellStyle, cellData.getOrCreateStyle());
    }
 
    @Override
    protected void setContentCellStyle(CellWriteHandlerContext context) {
        if (stopProcessing(context) || CollectionUtils.isEmpty(contentWriteCellStyleList)) {
            return;
        }
        WriteCellData<?> cellData = context.getFirstCellData();
        if (context.getRelativeRowIndex() == null || context.getRelativeRowIndex() <= 0) {
            WriteCellStyle.merge(contentWriteCellStyleList.get(0), cellData.getOrCreateStyle());
        } else {
            WriteCellStyle.merge(
                contentWriteCellStyleList.get(context.getRelativeRowIndex() % contentWriteCellStyleList.size()),
                cellData.getOrCreateStyle());
        }
    }
 
    protected boolean stopProcessing(CellWriteHandlerContext context) {
        return context.getFirstCellData() == null;
    }
 
}

3、导出EXCEL

示例：根据第一列，合并0-7列上下临近单元格相同的数据

List<ExportDto> exportDtoVos = new ArrayList<ExportDto>();
response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
response.setCharacterEncoding(Charsets.UTF_8.name());
String yyyyMMddHHmmss = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyyMMddHHmmss"));
String fileName = URLEncoder.encode(yyyyMMddHHmmss+"_flow", Charsets.UTF_8.name());
response.setHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");
// 设置单元格样式
HorizontalCellStyleStrategy horizontalCellStyleStrategy =
        new HorizontalCellStyleStrategy(StyleUtils.getHeadStyle(), StyleUtils.getContentStyle());
int[] mergeColumeIndex = {0,1,2,3,4,5,6,7};
int mergeRowIndex = 1;
EasyExcel.write(response.getOutputStream(),ExportDto.class).registerWriteHandler(new ExcelFillCellLineMergeHandler(mergeRowIndex, mergeColumeIndex))
        .registerWriteHandler(horizontalCellStyleStrategy).sheet("sheet1").doWrite(exportDtoVos);

效果图：