java POI导出excel多个sheet

excel方法：
public class ExcelUtil {

public void exportExcel(XSSFWorkbook workbook, int sheetNum,
                            String sheetTitle, String[] headers, List<List<String>> result,
                            OutputStream out) throws Exception {
        // 生成一个表格
        XSSFSheet sheet = workbook.createSheet();
        workbook.setSheetName(sheetNum, sheetTitle);
        // 设置表格默认列宽度为20个字节
        sheet.setDefaultColumnWidth((short) 20);
        // 生成一个样式
        XSSFCellStyle style = workbook.createCellStyle();
        /* 设置这些样式 */
        ;
        style.setFillForegroundColor(HSSFColor.PALE_BLUE.index);
//        style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
//        style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
//        style.setBorderLeft(HSSFCellStyle.BORDER_THIN);
//        style.setBorderRight(HSSFCellStyle.BORDER_THIN);
//        style.setBorderTop(HSSFCellStyle.BORDER_THIN);
//        style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
        // 生成一个字体
        XSSFFont font = workbook.createFont();
        font.setColor(HSSFColor.BLACK.index);
        font.setFontHeightInPoints((short) 12);
        //font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
        // 把字体应用到当前的样式
        style.setFont(font);

        // 指定当单元格内容显示不下时自动换行
        style.setWrapText(true);

        // 产生表格标题行
        XSSFRow row = sheet.createRow(0);
        for (int i = 0; i < headers.length; i++) {
            XSSFCell cell = row.createCell((short) i);

            cell.setCellStyle(style);
            HSSFRichTextString text = new HSSFRichTextString(headers[i]);
            cell.setCellValue(text.toString());
        }
        // 遍历集合数据，产生数据行
        if (result != null) {
            int index = 1;
            for (List<String> m : result) {
                row = sheet.createRow(index);
                int cellIndex = 0;
                for (String str : m) {
                    XSSFCell cell = row.createCell((short) cellIndex);
                    cell.setCellValue(str);
                    cellIndex++;
                }
                index++;
            }
        }
    }
}

调用：

public void exportAllyScoreCount(HttpServletResponse response,List<ProcessOrder> processOrders,List<ProcessOrderBOM> bom){

   String fileName = System.currentTimeMillis()+"-"+".xlsx";
   try {
      response.setHeader("Content-Disposition", "attachment; filename=".concat(fileName));
      response.setHeader("Connection", "close");
      response.setHeader("Content-Type", "application/vnd.ms-excel");
      OutputStream ouputStream = response.getOutputStream();
      /*单信息列表*/
      List<List<String>> data0 = new ArrayList<List<String>>();
      List<ProcessOrder> tScoreTotalDtos =processOrders;

      for(ProcessOrder tScoreCountDto : tScoreTotalDtos){
         List rowData = new ArrayList();
         String d = String.valueOf(tScoreCountDto.getFinishTime());
         SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy",Locale.US);
         Date date1=sdf.parse(d);
         sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

         rowData.add(tScoreCountDto.getBatchId()); 

         rowData.add(String.valueOf(tScoreCountDto.getProductDetail()));

         data0.add(rowData);
      }
      /*生产计划BOM*/
      List<List<String>> data1 = new ArrayList<List<String>>();
      List<ProcessOrderBOM> tIndexDetais = bom;

      for(ProcessOrderBOM tIndexDetailDto : tIndexDetais){
         List rowData = new ArrayList();
         rowData.add(String.valueOf(tIndexDetailDto.getProjectCode()));
         rowData.add(String.valueOf(tIndexDetailDto.getNum()));
         data1.add(rowData);
      }
      String[] headers0 = { "订单号（批次号）\n"};
      String[] headers1 = { "项目号\n","需求量\n"};

      ExcelUtil eeu = new ExcelUtil();
      XSSFWorkbook workbook = new XSSFWorkbook();
      eeu.exportExcel(workbook, 0, "单信息列表", headers0, data0, ouputStream);
      eeu.exportExcel(workbook, 1, "生产计划", headers1, data1, ouputStream);

      //原理就是将所有的数据一起写入，然后再关闭输入流。
      workbook.write(ouputStream);
      ouputStream.close();
   } catch (Exception e) {
      e.printStackTrace();
   }
}