POI：excel导出，合并单元格

public ResponseEntity<byte[]> exportExcel(Op300 record) throws UnsupportedEncodingException {
		List<Op300> list = op300Mapper.select4excel(record);
		XSSFWorkbook workbook=new XSSFWorkbook();
        XSSFSheet sheet=workbook.createSheet("Sheet1");
        
        // 3.填写表头
        XSSFRow row=sheet.createRow(0);
        XSSFCell cell=row.createCell(0);
        cell.setCellValue("条码");
        XSSFCell cell1 = row.createCell(1);
        cell1.setCellValue("时间");
        XSSFCell cell2 = row.createCell(2);
        cell2.setCellValue("生产结果");
        
        XSSFCell cell3 = row.createCell(3);
        cell3.setCellValue("测试项");
        XSSFCell cell4 = row.createCell(4);
        cell4.setCellValue("测试值");
        XSSFCell cell5 = row.createCell(5);
        cell5.setCellValue("测试上限");
        XSSFCell cell6 = row.createCell(6);
        cell6.setCellValue("测试下限");
        XSSFCell cell7 = row.createCell(7);
        cell7.setCellValue("测试结果");
        
        int i=1;
        for (Op300 op300 : list) {
//			XSSFRow rowi = sheet.createRow(i++);
			String testXiang = op300.getTestXiang();
			String testZhi = op300.getTestZhi();
			String testShangXian = op300.getTestShangXian();
			String testXiaXian = op300.getTestXiaXian();
			String testResult = op300.getTestResult();
			String[] xiangArr = testXiang.split(",");
			String[] zhiArr = testZhi.split(",");
			String[] shangXianArr = testShangXian.split(",");
			String[] xiaXianArr = testXiaXian.split(",");
			String[] resultArr = testResult.split(",");
			
			int start =i;
			for(int j=0;j<xiangArr.length;j++) {
				XSSFRow rowi = sheet.createRow(i++);
				if(j==0) {
					rowi.createCell(0).setCellValue(op300.getBarCode());
					rowi.createCell(1).setCellValue(op300.getTime());
					rowi.createCell(2).setCellValue(op300.getProductResult());
				}
				rowi.createCell(3).setCellValue(xiangArr[j]);
				rowi.createCell(4).setCellValue(zhiArr[j]);
				rowi.createCell(5).setCellValue(shangXianArr[j]);
				rowi.createCell(6).setCellValue(xiaXianArr[j]);
				rowi.createCell(7).setCellValue(resultArr[j]);
				
			}
			int end =i-1;
            // 合并单元格
			CellRangeAddress mergedRegion = new CellRangeAddress(
	            start, end,  // 行范围：start到end（包含）
	            0, 0   // 列范围：0到0（包含）
	        );
	        sheet.addMergedRegion(mergedRegion);
	        CellRangeAddress mergedRegion2 = new CellRangeAddress(
	            start, end,  // 行范围：start到end（包含）
	            1, 1   // 列范围：1到1（包含）
	        );
	        sheet.addMergedRegion(mergedRegion2);
	        CellRangeAddress mergedRegion3 = new CellRangeAddress(
        		start, end,  // 行范围：start到end（包含）
        		2, 2   // 列范围：2到2（包含）
    		);
	        sheet.addMergedRegion(mergedRegion3);
		        
		}
        
        
        //创建一个字节数组输出流对象
        ByteArrayOutputStream outputStream=new ByteArrayOutputStream();
        try {
     	   //将excel写入输出流
            workbook.write(outputStream);
            workbook.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
     
	     HttpHeaders headers=new HttpHeaders();
	     String fileName=new String("excel.xlsx".getBytes("UTF-8"),"iso-8859-1");
	     headers.setContentDispositionFormData("attachment", fileName);
	     headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
	     
	     ResponseEntity<byte[]> returnFile=new ResponseEntity<byte[]>
	                         (outputStream.toByteArray(),headers,HttpStatus.CREATED);
	     try {
	         outputStream.close();
	     } catch (IOException e) {
	         e.printStackTrace();
	     }
			
		return returnFile;
	}