poi框架excel导出合并列

HSSFRow row = sheet.createRow(i);
     for (int j = 0; j < headerRow.size(); j++) {
      HashMap map=(HashMap) headerRow.get(j);
       short rowspan=Short.valueOf( map.get("rowspan")+"");
       short rowend=(short)(rowstart+rowspan-1);
       HSSFCell cell = row.createCell((short)rowstart);
       //导出前先设置，而且值设置在第一个框中
       cell.setCellValue(new String(String.valueOf(map.get("value")).getBytes(),"UTF-8"));

cell.setEncoding(HSSFCell.ENCODING_UTF_16);//设置单元格编码防止乱码

       //四个参数分别是：起始行，起始列，结束行，结束列 
       sheet.addMergedRegion(new Region(colstart, rowstart, colend,rowend ));
                      // cell.setCellStyle(HSSFCellStyle.)
      
      
                       rowstart=(short)(rowend+1);
                    
     }
       colstart=colend+1;
             }