java POI导出excel表格

1、异常java.lang.NoClassDefFoundError: org/apache/poi/UnsupportedFileFormatException

　　解决方法:使用的poi的相关jar包一定版本一定要相同！！！！！

 2.引入jar包

<!-- 导出excel -->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.9</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.9</version>
</dependency>

3.设置工作簿

//创建工作簿
HSSFWorkbook workbook = new HSSFWorkbook()
//添加工作簿名称
HSSFSheet  sheet = workbook.createSheet("考勤统计");
//创建单元格
HSSFRow  row = sheet.createRow(0);
//创建字体
HSSFFont font = workbook.createFont();
 font.setFontHeight((short) 200);
//创建样式
HSSFCellStyle style = workbook.createCellStyle();
//强制换行
style.setWrapText(true);
//添加字体
 style.setFont(font);

//合并单元格(起始行，结束行，起始列，结束列)
CellRangeAddress timeRegion = new CellRangeAddress(1, 2,0,0);
sheet.addMergedRegion(timeRegion);
//设置单元格内容
 timeCell.setCellValue("时间");

4.下载表格

HttpServletResponse response = servletRequestAttributes.getResponse();
        try {
            OutputStream out = response.getOutputStream();
            //设置格式 
            response.setCharacterEncoding("UTF-8");
            response.setContentType("application/ms-excel;charset=UTF-8");
            //设置请求头
            response.setHeader("Content-Disposition", "attachment;filename=".concat(String.valueOf(URLEncoder.encode(DateTimeUtil.getStartAndLastDayNumber(startDay, endDay) + ".xls", "UTF-8"))));
            response.setHeader("Access-Control-Expose-Headers", "Content-Disposition");
            //写入
            workbook.write(out);
            out.close();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }