基于poi动态合并表格
-首先看下效果图
左边为主表数据，右边为子表数据，可以根据自己的需求进行修改，下面来看下代码。
引入依赖
<!--poi--><dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml</artifactId><version>4.1.0</version></dependency>
创建一个PoiExcel类
先构造数据，根据表格，主子表是有相关联的，所以将主子表数据存入一个map集合中，主表的值作为map的key，value对应子表的list集合，可参考下面代码：
String[] masterHead = {"学号","姓名","专业"};String[] childHead = {"课程名称","上课地点","任课教师","上课时间"};List<String[]> childList = new ArrayList<>();childList.add(new String[]{"Java程序设计","1号楼302","雷老师","/8/30 15:53:49"});childList.add(new String[]{"数据结构","1号楼305","雷老师","/8/30 9:18:28"});List<String[]> childList1 = new ArrayList<>();childList1.add(new String[]{"计算机网络","2号楼301","方老师","/8/30 15:53:49"});List<Map<String,List<String[]>>> masterList = new ArrayList<>();Map<String,List<String[]>> map = new HashMap();map.put("0211-张晓-计算机与科学",childList);map.put("0212-于丽-电子信息工程",childList1);masterList.add(map);
然后创建一个Excel工作薄对象
//创建Excel工作薄对象HSSFWorkbook workbook=new HSSFWorkbook();//创建Excel工作表对象HSSFSheet sheet = workbook.createSheet("wj");//设置单元格居中HSSFCellStyle cellStyle = workbook.createCellStyle();cellStyle.setAlignment(HorizontalAlignment.CENTER);
然后根据需求一行行来给工作表格填充数据，首先是复杂表头，第一行是主表和子表，主表和子表的是合并列，根据主子表头的长度来确定，合并的列数；第二行是表头，根据主子表头的数组来填充。
//创建行的单元格，从0开始HSSFRow row = sheet.createRow(0);//创建统计单元格HSSFCell masterCell=row.createCell(0);//赋值masterCell.setCellValue("主表");masterCell.setCellStyle(cellStyle);//合并列CellRangeAddress region=new CellRangeAddress(0, 0, 0, masterHead.length-1);sheet.addMergedRegion(region);//创建详情单元格 从统计单元格的后一格开始创建HSSFCell childCell = row.createCell(masterHead.length);//赋值childCell.setCellValue("子表");childCell.setCellStyle(cellStyle);//合并列region=new CellRangeAddress(0, 0, masterHead.length, masterHead.length+childHead.length-1);sheet.addMergedRegion(region);//表头 从1开始HSSFRow titleRow = sheet.createRow(1);//主表头for (int i = 0; i < masterHead.length ; i++) {HSSFCell msCell = titleRow.createCell(i);msCell.setCellStyle(cellStyle);msCell.setCellValue(masterHead[i]);}//子表头for (int i = 0; i < childHead.length; i++) {HSSFCell chcell = titleRow.createCell(masterHead.length+i);chcell.setCellStyle(cellStyle);chcell.setCellValue(childHead[i]);}
这样就将第一行和第二行的表头填充上了，然后再填充对应的数据，先填充的是主表，主表的值我是用“-”来进行分隔的，所以用字符串进行切割成数组，然后拿到主表数据和对应的子表数据，工作簿的前2行都是表头，所以填充数据是从第三行开始，所以行下标为2，然后从第三行开始创建行，填充主表的数据，填充时要判断下子表的list的大小，大于一才需要进行合并，填充完主表后再填充子表，子表不需要合并，就一行行填充，代码如下：
//填充数据int lastRowIndex = 2; //记录最后行位置for (Map<String,List<String[]>> m : masterList){for (String key : m.keySet()){String[] ms = key.split("-");List<String[]> chlist = m.get(key);HSSFRow valueRow = sheet.createRow(lastRowIndex);for (int i = 0; i < ms.length ; i++) {HSSFCell mscell = valueRow.createCell(i);mscell.setCellStyle(cellStyle);mscell.setCellValue(ms[i]);if (chlist.size()>1){//子表数量大于1才进行 行合并region=new CellRangeAddress(lastRowIndex, lastRowIndex+chlist.size()-1, i, i);sheet.addMergedRegion(region);}}for (int i = 0; i < chlist.size(); i++) {String[] chstrs = chlist.get(i);HSSFRow chRow;if (i == 0){//避免重复创建 覆盖主表数据chRow = valueRow;}else {chRow = sheet.createRow(lastRowIndex);}lastRowIndex++;for (int j = 0; j < chstrs.length; j++) {HSSFCell chcell = chRow.createCell(ms.length+j);chcell.setCellStyle(cellStyle);chcell.setCellValue(chstrs[j]);}}}}
其中最重要的一句代码就是：
new CellRangeAddress(int firstRow, int lastRow, int firstCol, int lastCol)
这句代码就是合并单元格，参数1：起始行 参数2：终止行 参数3：起始列 参数4：终止列
最后看下PoiExcel类的完整代码
import org.apache.poi.hssf.usermodel.*;import org.apache.poi.ss.usermodel.HorizontalAlignment;import org.apache.poi.ss.util.CellRangeAddress;import javax.servlet.http.HttpServletResponse;import java.io.OutputStream;import .URLEncoder;import java.util.*;/*** @author huao* @Date /8/31 13:50* @description:*/public class PoiExcel {public static void excelport(HttpServletResponse response) throws Exception {//数据来源 通过参数传入String[] masterHead = {"学号","姓名","专业"};String[] childHead = {"课程名称","上课地点","任课教师","上课时间"};List<String[]> childList = new ArrayList<>();childList.add(new String[]{"Java程序设计","1号楼302","雷老师","/8/30 15:53:49"});childList.add(new String[]{"数据结构","1号楼305","雷老师","/8/30 9:18:28"});List<String[]> childList1 = new ArrayList<>();childList1.add(new String[]{"计算机网络","2号楼301","方老师","/8/30 15:53:49"});List<Map<String,List<String[]>>> masterList = new ArrayList<>();Map<String,List<String[]>> map = new HashMap();map.put("0211-张晓-计算机与科学",childList);map.put("0212-于丽-电子信息工程",childList1);masterList.add(map);//创建Excel工作薄对象HSSFWorkbook workbook=new HSSFWorkbook();//创建Excel工作表对象HSSFSheet sheet = workbook.createSheet("wj");//设置单元格居中HSSFCellStyle cellStyle = workbook.createCellStyle();cellStyle.setAlignment(HorizontalAlignment.CENTER);//创建行的单元格，从0开始HSSFRow row = sheet.createRow(0);//创建统计单元格HSSFCell masterCell=row.createCell(0);//赋值masterCell.setCellValue("主表");masterCell.setCellStyle(cellStyle);//合并列CellRangeAddress region=new CellRangeAddress(0, 0, 0, masterHead.length-1);sheet.addMergedRegion(region);//创建详情单元格 从统计单元格的后一格开始创建HSSFCell childCell = row.createCell(masterHead.length);//赋值childCell.setCellValue("子表");childCell.setCellStyle(cellStyle);//合并列region=new CellRangeAddress(0, 0, masterHead.length, masterHead.length+childHead.length-1);sheet.addMergedRegion(region);//表头 从1开始HSSFRow titleRow = sheet.createRow(1);//主表头for (int i = 0; i < masterHead.length ; i++) {HSSFCell msCell = titleRow.createCell(i);msCell.setCellStyle(cellStyle);msCell.setCellValue(masterHead[i]);}//子表头for (int i = 0; i < childHead.length; i++) {HSSFCell chcell = titleRow.createCell(masterHead.length+i);chcell.setCellStyle(cellStyle);chcell.setCellValue(childHead[i]);}//填充数据int lastRowIndex = 2; //记录最后行位置for (Map<String,List<String[]>> m : masterList){for (String key : m.keySet()){String[] ms = key.split("-");List<String[]> chlist = m.get(key);HSSFRow valueRow = sheet.createRow(lastRowIndex);for (int i = 0; i < ms.length ; i++) {HSSFCell mscell = valueRow.createCell(i);mscell.setCellStyle(cellStyle);mscell.setCellValue(ms[i]);if (chlist.size()>1){//子表数量大于1才进行 行合并region=new CellRangeAddress(lastRowIndex, lastRowIndex+chlist.size()-1, i, i);sheet.addMergedRegion(region);}}for (int i = 0; i < chlist.size(); i++) {String[] chstrs = chlist.get(i);HSSFRow chRow;if (i == 0){//避免重复创建 覆盖主表数据chRow = valueRow;}else {chRow = sheet.createRow(lastRowIndex);}lastRowIndex++;for (int j = 0; j < chstrs.length; j++) {HSSFCell chcell = chRow.createCell(ms.length+j);chcell.setCellStyle(cellStyle);chcell.setCellValue(chstrs[j]);}}}}String fileName = URLEncoder.encode("POIExcel下载测试","UTF-8");response.setContentType("application/octet-stream;charset=UTF-8");response.setHeader("Content-Disposition","attachment;filename="+fileName+".xls");OutputStream os = response.getOutputStream();workbook.write(os);os.flush();os.close();workbook.close();}}
然后controller层的代码：
import com.example.demo.utils.PoiExcel;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import javax.servlet.http.HttpServletResponse;/*** @author huao* @Date /8/31 13:56* @description:*/@RestController@RequestMapping("/demo")public class DemoWeb {@RequestMapping("/download")public void download(HttpServletResponse response) throws Exception {PoiExcel.excelport(response);}}
导入依赖后代码复制过去可直接使用。
写作原因：看着网上很多动态合并单元格的例子，但是都看不懂，可能是我太菜了，所以自己撸了一个，这个代码量算是很少了吧，如果有什么不清楚的欢迎评论区留言或者私信我。
