Java整合EasyExcel实战——3(上下列相同合并单元格策略)
参考：https://juejin.cn/post/7322156759443095561?searchId=202405262043517631094B7CCB463FDA06
https://juejin.cn/post/7322156759443095561?searchId=202405262043517631094B7CCB463FDA06
准备条件
依赖
<dependency><groupId>com.alibaba</groupId><artifactId>easyexcel</artifactId><version>2.2.6</version></dependency>工具类
package co.yixiang.exam.listener;import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.write.handler.CellWriteHandler;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteTableHolder;
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;public class ExcelFillCellMergeStrategy implements CellWriteHandler {private int[] mergeColumnIndex;private int mergeRowIndex;public ExcelFillCellMergeStrategy() {}public ExcelFillCellMergeStrategy(int mergeRowIndex, int[] mergeColumnIndex) {this.mergeRowIndex = mergeRowIndex;this.mergeColumnIndex = mergeColumnIndex;}@Overridepublic void beforeCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row, Head head, Integer columnIndex, Integer relativeRowIndex, Boolean isHead) {}@Overridepublic void afterCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {}@Overridepublic void afterCellDataConverted(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, CellData cellData, Cell cell, Head head, Integer integer, Boolean aBoolean) {}@Overridepublic void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, List<CellData> 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;}}}}/*** 当前单元格向上合并** @param writeSheetHolder* @param cell 当前单元格* @param curRowIndex 当前行* @param curColIndex 当前列*/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();Cell preCell = cell.getSheet().getRow(curRowIndex - 1).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);}}}}
ServiceImpl层应用
sql 数据的重复数据，合并单元格
SELECTeq.id,eq.question_title,eo.options_content,eq.options_correct,eq.question_answer,eq.question_score,eq.question_subject,eq.question_title_zi,eq.question_type
FROMex_question eq
LEFT JOINex_options eoon eq.id = eo.question_id where eq.is_del = 0 and eo.is_del = 0;
@Overridepublic R exportExQuestionOptions(HttpServletResponse response) throws IOException {// 定义导出的Excel文件名String fileName = "test.xlsx";// 设置响应的内容类型为二进制流，这是文件下载的标准设置response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);// 设置响应头的Content-Disposition，使用"attachment"指示浏览器这是一个需要下载的文件response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=" + URLEncoder.encode(fileName, StandardCharsets.UTF_8.toString()));// 查询需要导出的数据 (包含复杂数据)List<ExExcelQuestionOptionsDto> questionsOptionsAll = exQuestionMapper.getQuestionsOptionsAll();// 假设我们要合并第1行和第2列到第4列的数据（索引从0开始）int mergeRowIndex = 0; // 行索引 int[] mergeColumnIndex = new int[]{0,1,2,3,4,5,6}; // 列索引数组 要合并的列ExcelFillCellMergeStrategy excelFillCellMergeStrategy = new ExcelFillCellMergeStrategy(mergeRowIndex, mergeColumnIndex);EasyExcel.write(response.getOutputStream(), ExExcelQuestionOptionsDto.class).registerWriteHandler(excelFillCellMergeStrategy).sheet("测试").doWrite(questionsOptionsAll);return R.success();}