import java.io.Serializable;/*** POI Excel报表导出，列合并实体<br>* * @author WQ**/
public class PoiModel implements Serializable{/*** */private static final long serialVersionUID = 1L;private String content;  private String oldContent;  private int rowIndex;  private int 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 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 PoiModel() {}public PoiModel(String content, String oldContent, int rowIndex,int cellIndex) {this.content = content;this.oldContent = oldContent;this.rowIndex = rowIndex;this.cellIndex = cellIndex;}@Overridepublic String toString() {return "PoiModel [content=" + content + ", oldContent=" + oldContent+ ", rowIndex=" + rowIndex + ", cellIndex=" + cellIndex + "]";}  }

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;public class Demo {/** * @param title 标题集合 tilte的长度应该与list中的model的属性个数一致 * @param maps 内容集合 * @param mergeIndex 合并单元格的列 */  public static String createExcel(String[] title, Map<String, List<Map<String, String>>> maps, int[] mergeIndex){  if (title.length==0){  return null;  }  /*初始化excel模板*/  Workbook workbook = new XSSFWorkbook();  Sheet sheet = null;  int n = 0;  for(Map.Entry<String, List<Map<String, String>>> entry : maps.entrySet()){  try {  sheet = workbook.createSheet();  workbook.setSheetName(n, entry.getKey());  workbook.setSelectedTab(0);  }catch (Exception e){  e.printStackTrace();  }  /*初始化head，填值标题行（第一行）*/  Row row0 = sheet.createRow(0);  for(int i = 0; i<title.length; i++){  /*创建单元格，指定类型*/  Cell cell_1 = row0.createCell(i, Cell.CELL_TYPE_STRING);  cell_1.setCellValue(title[i]);  }  /*得到当前sheet下的数据集合*/  List<Map<String, String>> list = entry.getValue();  /*遍历该数据集合*/  List<PoiModel> poiModels = new ArrayList();  if(null!=workbook){  Iterator iterator = list.iterator();  int index = 1;while (iterator.hasNext()){  Row row = sheet.createRow(index);  /*取得当前这行的map，该map中以key，value的形式存着这一行值*/  Map<String, String> map = (Map<String, String>)iterator.next();  /*循环列数，给当前行塞值*/  for(int i = 0; i<title.length; i++){  String old = "";  /*old存的是上一行统一位置的单元的值，第一行是最上一行了，所以从第二行开始记*/  if(index > 1){  old = poiModels.get(i)==null?"":poiModels.get(i).getContent();  }  /*循环需要合并的列*/  for(int j = 0; j < mergeIndex.length; j++){  if(index == 1){  /*记录第一行的开始行和开始列*/  PoiModel poiModel = new PoiModel();  poiModel.setOldContent(map.get(title[i]));  poiModel.setContent(map.get(title[i]));  poiModel.setRowIndex(1);  poiModel.setCellIndex(i);  poiModels.add(poiModel);  break;  }else if(i > 0 && mergeIndex[j] == i){/*这边i>0也是因为第一列已经是最前一列了，只能从第二列开始*/  /*当前同一列的内容与上一行同一列不同时，把那以上的合并, 或者在当前元素一样的情况下，前一列的元素并不一样，这种情况也合并*/  /*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，把下面条件中　　　　　　　　　　　　　　　　　　||poiModels.get(i).getContent().equals(map.get(title[i])) && !poiModels.get(i - 1).getOldContent().equals(map.get(title[i-1]))去掉就行*/  if(!poiModels.get(i).getContent().equals(map.get(title[i])) || poiModels.get(i).getContent().equals(map.get(title[i])) 　　　　　　　　　　　　　　　　　　　　&& !poiModels.get(i - 1).getOldContent().equals(map.get(title[i-1]))){  /*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*/  CellRangeAddress cra=new CellRangeAddress(poiModels.get(i).getRowIndex(), index - 1, poiModels.get(i).getCellIndex(), poiModels.get(i).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*/  poiModels.get(i).setContent(map.get(title[i]));  poiModels.get(i).setRowIndex(index);  poiModels.get(i).setCellIndex(i);  }  }  /*处理第一列的情况*/  if(mergeIndex[j] == i && i == 0 && !poiModels.get(i).getContent().equals(map.get(title[i]))){  /*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*/  CellRangeAddress cra=new CellRangeAddress(poiModels.get(i).getRowIndex(), index - 1, poiModels.get(i).getCellIndex(), poiModels.get(i).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*/  poiModels.get(i).setContent(map.get(title[i]));  poiModels.get(i).setRowIndex(index);  poiModels.get(i).setCellIndex(i);  }  /*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(mergeIndex[j] == i && index == list.size()){  CellRangeAddress cra=new CellRangeAddress(poiModels.get(i).getRowIndex(), index, poiModels.get(i).getCellIndex(), poiModels.get(i).getCellIndex());  //在sheet里增加合并单元格
                                sheet.addMergedRegion(cra);  }  }  Cell cell = row.createCell(i, Cell.CELL_TYPE_STRING);  cell.setCellValue(map.get(title[i]));  /*在每一个单元格处理完成后，把这个单元格内容设置为old内容*/  poiModels.get(i).setOldContent(old);  }  index++;  }  }  n++;  }  /*生成临时文件*/  FileOutputStream out = null;  String localPath = null;  File tempFile = null;  String fileName = String.valueOf(new Date().getTime()/1000);  try {  tempFile = File.createTempFile(fileName, ".xlsx");  localPath = tempFile.getAbsolutePath();  out = new FileOutputStream(localPath);  workbook.write(out);  }catch (IOException e){  e.printStackTrace();  }finally {  try {  out.flush();  out.close();  }catch (IOException e){  e.printStackTrace();  }  }  return localPath;  }  public static void main(String[] args) throws IOException{  /*此处标题的数组则对应excel的标题*/  String[] title = {"id","标题","描述","负责人","开始时间"};  List<Map<String, String>> list = new ArrayList();  /*这边是制造一些数据，注意每个list中map的key要和标题数组中的元素一致*/  for(int i = 0; i<10; i++){  HashMap<String, String> map = new HashMap();  if(i > 5){  if(i<7){  map.put("id","333");  map.put("标题","mmmm");  }else {  map.put("id","333");  map.put("标题","aaaaa");  }  }else if (i >3){  map.put("id","222");  map.put("标题","哈哈哈哈");  }else if (i>1 && i<3){  map.put("id","222");  map.put("标题","hhhhhhhh");  }else {  map.put("id","222");  map.put("标题","bbbb");  }  map.put("描述","sssssss");  map.put("负责人","vvvvv");  map.put("开始时间","2017-02-27 11:20:26");  list.add(map);  }  Map<String, List<Map<String, String>>> map = new HashMap();  map.put("测试合并数据", list);  System.out.println(createExcel(title, map, new int[]{0,1,2}));  }  }