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零、希望Springboot-java导出excel文件，包括动态表头与下边合并的列

使用 org.apache.poi 与自己封装工具类实现相关功能。代码如下

一、代码

1、依赖

    implementation(group: 'org.apache.poi',name: 'poi-ooxml',version: '4.1.0')implementation(group: 'org.apache.poi',name: 'poi',version: '4.1.0')implementation(group: 'cn.hutool', name: 'hutool-all', version: '5.8.3')

2、工具类 ExcelMergeUtil.java

import cn.hutool.json.JSONUtil;
import com.longze.fengqx.HeaderNode;
import com.longze.fengqx.PoiModel;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.ss.util.RegionUtil;
import org.apache.poi.xssf.streaming.SXSSFCell;
import org.apache.poi.xssf.streaming.SXSSFSheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.IntStream;/*** @author Fengqx* @version 1.0* @description: excel文件合并* @date 2023/8/20 13:13*/
public class ExcelMergeUtil {public static SXSSFSheet createExcelHead(SXSSFWorkbook book, String sheetName, String headJson){List<HeaderNode> headerNodes = JSONUtil.toList(headJson, HeaderNode.class);SXSSFSheet sxssfSheet = book.createSheet(sheetName);CellStyle headStyle = book.createCellStyle();defaultHeadStyle(headStyle);//表头层级int deep = headerNodes.stream().map(HeaderNode::getRow).reduce(Integer::max).orElse(1);for (int i = 0; i < deep; i++) {sxssfSheet.createRow(i);}//创建单元格for (HeaderNode headerNode : headerNodes) {int row = headerNode.getRow();int col = headerNode.getColumn();SXSSFCell sxssfCell = sxssfSheet.getRow(row).createCell(col);sxssfSheet.setColumnWidth(col, headerNode.getWidth() * 256);sxssfCell.setCellStyle(headStyle);sxssfCell.setCellValue(headerNode.getHeaderName());CellRangeAddress region;//是否跨列if (headerNode.isOverNode()) {region = new CellRangeAddress(row, deep, col, col);} else {region = new CellRangeAddress(row, row, col, (col + headerNode.getOverNodeCount() - 1));}if (region.getNumberOfCells() > 1) {sxssfSheet.addMergedRegionUnsafe(region);//合并后设置下边框RegionUtil.setBorderTop(BorderStyle.THIN, region, sxssfSheet);RegionUtil.setBorderLeft(BorderStyle.THIN, region, sxssfSheet);RegionUtil.setBorderBottom(BorderStyle.THIN, region, sxssfSheet);RegionUtil.setBorderRight(BorderStyle.THIN, region, sxssfSheet);}}return sxssfSheet;}public static void mergeCellFunc(Sheet sheet, String[] title, String[] field, List<Map<String, String>> list, Integer deep,List<Integer> mergeIndex){Map<String, List<Map<String, String>>> map = Maps.newHashMap();map.put("测试合并数据", list);// 模拟大数据量情况下，任务中心可分页查询接口，分批返回数据List<List<Map<String, String>>> listList =excelPageByNum(list, 5);// 数据总数 + 表头int size = listList.stream().mapToInt(List::size).sum() + deep;List<PoiModel> poiModels = Lists.newArrayList();for (List<Map<String, String>> listmid : listList) {for (Map<String, String> mapMid : listmid) {int index = sheet.getLastRowNum()+1;Row row = sheet.createRow(index);for (int i = 0; i < title.length; i++) {String titleField = field[i];String old = null;if (index > deep+1) {old = poiModels.get(i) == null ? null : poiModels.get(i).getContent();}for (int k : mergeIndex) {if (index == deep+1) {PoiModel poiModel =new PoiModel(mapMid.get(titleField),mapMid.get(titleField),null,deep+1,i);poiModels.add(poiModel);break;}PoiModel poiModel = poiModels.get(i);String content = mapMid.get(titleField);// 当前行的当前列与上一行的当前列的内容不一致时，则把当前行以上的合并if (i > 0 && k == i) {// 如果不需要考虑当前行与上一行内容相同，但是它们的前一列内容不一样则不合并的情况，把或条件删除if (!StringUtils.equalsIgnoreCase(content, poiModel.getContent())
//                                    || (StringUtils.equalsIgnoreCase(content, poiModel.getContent()) && !StringUtils.equalsIgnoreCase(poiModels.get(i - 1).getOldContent(),mapMid.get(field[i - 1])))) {get(poiModel, content, index, i, sheet);}}// 处理第一列的情况if (k == i && i == 0 && !StringUtils.equalsIgnoreCase(content,poiModel.getContent())) {get(poiModel, content, index, i, sheet);}// 最后一行没有后续的行与之比较，所有当到最后一行时则直接合并对应列的相同内容if (k == i && index == size && poiModels.get(i).getRowIndex() != index) {CellRangeAddress cra = new CellRangeAddress(poiModels.get(i).getRowIndex(), index, poiModels.get(i).getCellIndex(), poiModels.get(i).getCellIndex());sheet.addMergedRegion(cra);}}Cell cell = row.createCell(i);cell.setCellValue(mapMid.get(titleField));poiModels.get(i).setOldContent(old);}}}}/*** 表头样式** @param headStyle*/private static void defaultHeadStyle(CellStyle headStyle) {headStyle.setBorderTop(BorderStyle.THIN);headStyle.setBorderLeft(BorderStyle.THIN);headStyle.setBorderBottom(BorderStyle.THIN);headStyle.setBorderRight(BorderStyle.THIN);headStyle.setAlignment(HorizontalAlignment.CENTER);headStyle.setVerticalAlignment(VerticalAlignment.CENTER);headStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);headStyle.setFillForegroundColor(IndexedColors.YELLOW.getIndex());}//合并单元格private static void get(PoiModel poiModel, String content, int index, int i, Sheet sheet) {if (poiModel.getRowIndex() != index - 1) {CellRangeAddress cra = new CellRangeAddress(poiModel.getRowIndex(), index - 1, poiModel.getCellIndex(), poiModel.getCellIndex());//在sheet里增加合并单元格sheet.addMergedRegion(cra);}/*重新记录该列的内容为当前内容，行标记改为当前行标记，列标记则为当前列*/poiModel.setContent(content);poiModel.setRowIndex(index);poiModel.setCellIndex(i);}public static <T> List<List<T>> excelPageByNum(List<T> list, int pageSize) {return IntStream.range(0, list.size()).boxed().filter(t -> t % pageSize == 0).map(t -> list.stream().skip(t).limit(pageSize).collect(Collectors.toList())).collect(Collectors.toList());}
}

3、实体对象

HeaderNode.java  和 PoiModel.java

public class PoiModel {private String content;private String oldContent;private String primaryKey;private int rowIndex;private int cellIndex;public PoiModel() {}public PoiModel(String content, String oldContent, String primaryKey, int rowIndex, int cellIndex) {this.content = content;this.oldContent = oldContent;this.primaryKey = primaryKey;this.rowIndex = rowIndex;this.cellIndex = cellIndex;}public String getContent() {return content;}public void setContent(String content) {this.content = content;}public String getOldContent() {return oldContent;}public void setOldContent(String oldContent) {this.oldContent = oldContent;}public String getPrimaryKey() {return primaryKey;}public void setPrimaryKey(String primaryKey) {this.primaryKey = primaryKey;}public int getRowIndex() {return rowIndex;}public void setRowIndex(int rowIndex) {this.rowIndex = rowIndex;}public int getCellIndex() {return cellIndex;}public void setCellIndex(int cellIndex) {this.cellIndex = cellIndex;}
}public class HeaderNode {/*** 标题头*/private String headerName;/*** 层级*/private int row;/*** 非叶子节点列跨度*/private int overNodeCount;/*** 当前列没有子节点*/private boolean overNode = true;/*** 列*/private int column;/*** 宽度*/private int width = 13;public String getHeaderName() {return headerName;}public void setHeaderName(String headerName) {this.headerName = headerName;}public int getRow() {return row;}public void setRow(int row) {this.row = row;}public int getOverNodeCount() {return overNodeCount;}public void setOverNodeCount(int overNodeCount) {this.overNodeCount = overNodeCount;}public boolean isOverNode() {return overNode;}public void setOverNode(boolean overNode) {this.overNode = overNode;}public int getColumn() {return column;}public void setColumn(int column) {this.column = column;}public int getWidth() {return width;}public void setWidth(int width) {this.width = width;}
}

4、下载Controller

 @GetMapping(value = "/downExcel")@ResponseBodypublic void downExcel(HttpServletResponse response,@RequestParam(required = true) String type) throws Exception {try {tengxunService.downExcel(response, type);} catch (Exception ex) {throw ex;}}

5、下载service

  @Overridepublic void downloadExcel(HttpServletResponse response, String type)throws Exception {response.setContentType("application/vnd.ms-excel");response.setCharacterEncoding("utf-8");// 这里URLEncoder.encode可以防止中文乱码String fileName = URLEncoder.encode("腾讯充值文件", "UTF-8");response.setHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");OutputStream os = response.getOutputStream();
//加工数据List<Map<String, String>> list = Lists.newArrayList();for(int i=0;i<chongzhiList.size();i++){Chongzhi dto=new Chongzhi ();list.add(JSONObject.parseObject(JSON.toJSONString(dto),Map.class));}String weekStart ="08.01";String weekEnd ="08.07";String nextWeekStart = "08.08";String nextWeekEnd ="08.15";//合并单元格方法try {String customizeLabel = "[{\"headerName\":\"区域\",\"column\":0,\"row\":0}," +"{\"headerName\":\"用户姓名\",\"column\":1,\"row\":0}," +"{\"headerName\":\"本周（"+weekStart+"-"+weekEnd+"）充值记录\",\"column\":2,\"row\":0}," +"{\"headerName\":\"本周（"+weekStart+"-"+weekEnd+"）充值详情\",\"column\":3,\"row\":0,\"overNodeCount\":4,\"overNode\":false},{\"headerName\":\"充值时间\",\"column\":3,\"row\":1}," +"{\"headerName\":\"充值项目\",\"column\":4,\"row\":\"1\"}," +"{\"headerName\":\"充值方式\",\"column\":5,\"row\":1}," +"{\"headerName\":\"充值金额\",\"column\":6,\"row\":1}," +"{\"headerName\":\"下周（"+nextWeekStart+"-"+nextWeekEnd+"）充值计划\",\"column\":7,\"row\":0}]";//1、生bookSXSSFWorkbook book = new SXSSFWorkbook();//2、生成动态标题SXSSFSheet sxssfSheet = ExcelMerge.createExcelHead(book,"Sheet1", customizeLabel);//3、取数据对应字段值  汇总String[] title = {"区域", "用户姓名", "本周（"+weekStart+"-"+weekEnd+"）充值记录", "充值时间", "充值项目", "充值方式", "充值金额", "下周（"+nextWeekStart+"-"+nextWeekEnd+"）充值计划"};//4、取数据对应属性的字段值  汇总String[] field = {"areaName", "name", "chongzjilu", "chongzTime", "chongzProject", "chongzMethod", "chongzMoney", "nextChongz"};//5、需要合并的列List<Integer> mergeIndex = Arrays.asList(0,1,7);//6、合并ExcelMerge.mergeCellFunc(sxssfSheet,title,field, list, sxssfSheet.getLastRowNum(),mergeIndex);//创建excel文件 下载book.write(os);} catch (IOException e){logger.error("文件导出失败,错误信息{}",e);// 重置responseresponse.reset();response.setContentType("application/json");response.setCharacterEncoding("utf-8");Map<String, String> map = new HashMap<>();map.put("statusCode", "500");map.put("message", "下载文件失败" + e.getMessage());response.getWriter().println(JSON.toJSONString(map));}finally {try {os.close();} catch (IOException e) {e.printStackTrace();}}}

三、下载

完事通过controller调用下载接口，直接可以下载出文件

可以任意改表头，与选择是否要合并的字段，当做参数传入，将需要合并的列顺序传入即可完成合并，一步到位，十分方便

//5、需要合并的列  
List<Integer> mergeIndex = Arrays.asList(0,1,7);

ExcelMerge.mergeCellFunc(sxssfSheet,title,field, list, sxssfSheet.getLastRowNum(),mergeIndex);

截图如下

荆轲刺秦王！