java文件导出excel

@RequestMapping(value = "/emp/export", method = RequestMethod.GET)
public void exportExcel(@RequestParam(value = "pageNum", defaultValue = "1") Integer pageNum, HttpServletResponse response) {

    PageInfo<Employee> pageInfo = employeeService.getAll(pageNum);//自定义导出的数据

    List<Employee> list = pageInfo.getList();

    try {
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        ExcelUtil.exportUserExcel(list, os);//拼装数据
        byte[] content = os.toByteArray();
        InputStream is = new ByteArrayInputStream(content);
        // 设置response参数，可以打开下载页面
        response.reset();
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");

        response.setHeader("Content-Disposition", "attachment;filename=aaa.xls");
        response.setContentLength(content.length);
        ServletOutputStream outputStream = response.getOutputStream();
        BufferedInputStream bis = new BufferedInputStream(is);
        BufferedOutputStream bos = new BufferedOutputStream(outputStream);
        byte[] buff = new byte[8192];
        int bytesRead;
        while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
            bos.write(buff, 0, bytesRead);
        }
        bis.close();
        bos.close();
        outputStream.flush();
        outputStream.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

/**
 * 将用户的信息导入到excel文件中去
 * @param userList 用户列表
 * @param out 输出表
 */
public static void exportUserExcel(List<Employee> userList, OutputStream out)
{
    try{
        //1.创建工作簿
        HSSFWorkbook workbook = new HSSFWorkbook();
        //1.1创建合并单元格对象
        CellRangeAddress callRangeAddress = new CellRangeAddress(0,0,0,4);//起始行,结束行,起始列,结束列
        //1.2头标题样式
        HSSFCellStyle headStyle = createCellStyle(workbook,(short)16);
        //1.3列标题样式
        HSSFCellStyle colStyle = createCellStyle(workbook,(short)13);
        //2.创建工作表
        HSSFSheet sheet = workbook.createSheet("用户列表");
        //2.1加载合并单元格对象
        sheet.addMergedRegion(callRangeAddress);
        //设置默认列宽
        sheet.setDefaultColumnWidth(25);
        //3.创建行
        //3.1创建头标题行;并且设置头标题
        HSSFRow row = sheet.createRow(0);
        HSSFCell cell = row.createCell(0);
    
        //加载单元格样式
        cell.setCellStyle(headStyle);
        cell.setCellValue("用户列表");
        
        //3.2创建列标题;并且设置列标题
        HSSFRow row2 = sheet.createRow(1);
        String[] titles = {"Id","姓名","电子邮箱","性别","部门Id","所属部门"};
        for(int i=0;i<titles.length;i++)
        {
            HSSFCell cell2 = row2.createCell(i);
            //加载单元格样式
            cell2.setCellStyle(colStyle);
            cell2.setCellValue(titles[i]);
        }
        
        
        //4.操作单元格;将用户列表写入excel
        if(userList != null)
        {
            for(int j=0;j<userList.size();j++)
            {
                //创建数据行,前面有两行,头标题行和列标题行
                HSSFRow row3 = sheet.createRow(j+2);
                HSSFCell cell1 = row3.createCell(0);
                cell1.setCellValue(userList.get(j).getEmpId());
                HSSFCell cell2 = row3.createCell(1);
                cell2.setCellValue(userList.get(j).getEmpName());
                HSSFCell cell3 = row3.createCell(2);
                cell3.setCellValue(userList.get(j).getEmail());
                HSSFCell cell4 = row3.createCell(3);
                cell4.setCellValue("M".equals(userList.get(j).getGender())?"男":"女");
                HSSFCell cell5 = row3.createCell(4);
                cell5.setCellValue(userList.get(j).getDepartment().getDeptId());
                HSSFCell cell6 = row3.createCell(5);
                cell6.setCellValue(userList.get(j).getDepartment().getDeptName());
            }
        }
        //5.输出
        workbook.write(out);
        workbook.close();
        //out.close();
    }catch(Exception e)
    {
        e.printStackTrace();
    }
}

前端直接点击<a href="/emp/export?pageNum=1">导出Excel文件</a>即可下载

前提是项目中必须引用以下jar包：

<dependency>
  <groupId>commons-fileupload</groupId>
  <artifactId>commons-fileupload</artifactId>
  <version>1.2.1</version>
</dependency>


<dependency>
  <groupId>commons-io</groupId>
  <artifactId>commons-io</artifactId>
  <version>2.3</version>
</dependency>