本篇内容介绍了“Java怎么使用EasyExcel进行单元格合并”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
1.项目场景：
简介：报销单导出要根据指定的excel模板去自动替换对应，然后重新生成一份新的excel。在给定的excel模板中，有部分字段进行了单元格合并，如下所示。
2.问题描述
由于一张报销单可能存在多条报销内容，可以看到，当超过模板中预先给定的一条时，则会自动换行，但换行时并不会自动依照模板中的样式进行单元格合并，如下所示。
3.原因分析：
首先可以直观的看到excel进行数据插入并自动换行的时候，换行的数据并没有按照上一行的样式进行自动合并。
于是便想着用代码把这几列手动合并，然后再加上边框样式就可以解决了。
解决方案：
需要注意的是，按照以上的思路，直接进行单元格合并，然后加上边框并不能直接解决问题。
需要将后边空的每一个单元格先创建出来，然后将其一块合并才可以解决，创建单元格代码在下方
CustomCellWriteHandler类中说明。
这也算是耗费一整天时间踩的坑。。。
public static void outExcelBalance(String modelFile, String newFile, Map<String, Object> map, List<FillDataExpense> fillData, HttpServletResponse response, String fileName){ //定义model模板中默认的行数 int firstRow = 7; //excel中表示第八行，即模板中默认的一条 int lastRow = 7; InputStream is = null; File file = new File(modelFile); File file1 = new File(newFile); //String file1Name = file1.getName(); BufferedInputStream bis = null; try { if (!file.exists()) { copyFileUsingJava7Files(file, file1); } //TODO 单元格样式 Set<Integer> rowsBorderSet= new HashSet<>(); CustomCellWriteHandler customCellWriteHandler = null; //TODO 单元格合并 List<CellRangeAddress> cellRangeAddresss = new ArrayList<>(); if (ListUtils.isNotNull(fillData)){ if (fillData.size() > 1){ //合并每条报销单的第3-10列 for (int i = 1; i < fillData.size(); i++) { firstRow++; lastRow++; cellRangeAddresss.add(new CellRangeAddress(firstRow, lastRow, 2, 9)); cellRangeAddresss.add(new CellRangeAddress(firstRow, lastRow, 10, 11)); rowsBorderSet.add(firstRow); } } } customCellWriteHandler = new CustomCellWriteHandler(rowsBorderSet); MyMergeStrategy myMergeStrategy = new MyMergeStrategy(cellRangeAddresss); ExcelWriter excelWriter = EasyExcel.write(newFile) //注册单元格式 .registerWriteHandler(customCellWriteHandler) //注册合并策略 .registerWriteHandler(myMergeStrategy) .withTemplate(modelFile).build(); WriteSheet writeSheet = EasyExcel.writerSheet().build(); FillConfig fillConfig = FillConfig.builder().forceNewRow(Boolean.TRUE).build(); if (!ListUtil.listIsEmpty(fillData)){ excelWriter.fill(fillData, fillConfig, writeSheet); //excelWriter.fill(fillData, fillConfig, writeSheet); } excelWriter.fill(map, writeSheet); excelWriter.finish(); response.setHeader("content-type", "text/plain"); response.setHeader("content-type", "application/x-msdownload;"); response.setContentType("text/plain; charset=utf-8"); response.setHeader("Content-Disposition", "attachment; filename=" + new String(fileName.getBytes("utf-8"),"ISO8859-1")); byte[] buff = new byte[1024]; OutputStream os = null; os = response.getOutputStream(); bis = new BufferedInputStream(new FileInputStream(file1)); int i = bis.read(buff); while (i != -1) { os.write(buff, 0, buff.length); os.flush(); i = bis.read(buff); } } catch (Exception e){ LOGGER.error(e.getMessage()); } finally { if (bis != null) { try { bis.close(); } catch (IOException e) { e.printStackTrace(); } } // 删除生成文件 } }单元格合并MyMergeStrategy类代码：
public class MyMergeStrategy extends AbstractMergeStrategy { //合并坐标集合 private List<CellRangeAddress> cellRangeAddresss; //构造 public MyMergeStrategy(List<CellRangeAddress> cellRangeAddresss) { this.cellRangeAddresss = cellRangeAddresss; } @Override protected void merge(Sheet sheet, Cell cell, Head head, Integer integer) { if (ListUtils.isNotNull(cellRangeAddresss)) { if (cell.getRowIndex() == 7 ) { for (CellRangeAddress item : cellRangeAddresss) { sheet.addMergedRegionUnsafe(item); } } } }}单元格样式CustomCellWriteHandler类代码：
public class CustomCellWriteHandler implements CellWriteHandler { private static final Logger LOGGER = LoggerFactory.getLogger(CustomCellWriteHandler.class); //标黄行宽集合 private Set<Integer> rowIndexs; //构造 public CustomCellWriteHandler(Set<Integer> rowIndexs) { this.rowIndexs = rowIndexs; } public CustomCellWriteHandler() { } @Override public void beforeCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row, Head head, Integer columnIndex, Integer relativeRowIndex, Boolean isHead) { LOGGER.info("beforeCellCreate~~~~"); } @Override public void afterCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) { LOGGER.info("afterCellCreate~~~~"); } @Override 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<CellData> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) { //获取工作簿// HSSFWorkbook wb = new HSSFWorkbook();// //获取sheet// HSSFSheet sheet = wb.createSheet();// HSSFRow row = sheet.createRow();// HSSFCellStyle style = wb.createCellStyle(); // 这里可以对cell进行任何操作 if (CollectionUtils.isNotEmpty(rowIndexs)) { Workbook workbook = writeSheetHolder.getSheet().getWorkbook(); CellStyle cellStyle = workbook.createCellStyle(); Sheet sheet = writeSheetHolder.getSheet(); cellStyle.setAlignment(new HSSFWorkbook().createCellStyle().getAlignment()); cellStyle.setBorderBottom(BorderStyle.THIN); //下边框 cellStyle.setBottomBorderColor(IndexedColors.BLACK.getIndex()); cellStyle.setBorderLeft(BorderStyle.THIN);//左边框 cellStyle.setBorderTop(BorderStyle.THIN);//上边框 cellStyle.setBorderRight(BorderStyle.THIN);//右边框 cellStyle.setWrapText(true);//自动换行 //字体// Font cellFont = workbook.createFont();// cellFont.setBold(true);// cellStyle.setFont(cellFont);// //标黄,要一起设置// cellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND); //设置前景填充样式// cellStyle.setFillForegroundColor(IndexedColors.YELLOW.getIndex());//前景填充色 if (rowIndexs.contains(cell.getRowIndex())) { Row row = null; //循环创建空白单元格 for (int i = 0; i < rowIndexs.size(); i++) { for (Integer rowIndex : rowIndexs){ //创建4-10列的空白格 row = sheet.getRow(rowIndex.intValue()); if (row == null){ row = sheet.createRow(rowIndex.intValue()); } for (int j = 3; j <= 9; j++) { //获取8行的cell列 cell = row.createCell(j); cell.setCellStyle(cellStyle); cell.setCellValue(" "); LOGGER.info("第{}行，第{}列创建空白格。", cell.getRowIndex(), j); } //创建12列的红白格 cell = row.createCell(11); cell.setCellStyle(cellStyle); cell.setCellValue(" "); LOGGER.info("第{}行，第11列创建空白格。", cell.getRowIndex()); //创建21列的空白格 cell = row.createCell(21); cell.setCellStyle(cellStyle); cell.setCellValue(" "); LOGGER.info("第{}行，第21列创建空白格。", cell.getRowIndex()); } } } } }}5.总结
核心步骤：
1. //创建单元格样式CustomCellWriteHandler customCellWriteHandler = new CustomCellWriteHandler(参数按需给定);2. //单元格进行合并List<CellRangeAddress> cellRangeAddresss = new ArrayList<>();//例如：从firstRow行到lastRow行的2列到9列合并 cellRangeAddresss.add(new CellRangeAddress(firstRow, lastRow, 2, 9)); cellRangeAddresss.add(new CellRangeAddress(firstRow, lastRow, 10, 11)); MyMergeStrategy myMergeStrategy = new MyMergeStrategy(cellRangeAddresss);3. //注册以上两种策略ExcelWriter excelWriter = EasyExcel.write(newFile) //注册单元格式 .registerWriteHandler(customCellWriteHandler) //注册合并策略 .registerWriteHandler(myMergeStrategy) .withTemplate(modelFile).build();说明：刚开始修复的时候，并没有想过后边每个空的单元格需要先创建出来，才可以进行合并。一直以为是工具类的问题，后来不断的翻阅解决方案，看到有说需要先进行创建空白单元格，然后再进行合并，最终完美解决了。
关于代码部分，由于是业务代码，中间夹杂了许多不需要的。
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