将数据库中数据导出为excel表格

public class Excel {

    private static Logger logger = LoggerFactory.getLogger(Excel.class);

    /**
     * 导出项目列表
     *
     * @param jsonArray
     * @param request
     * @param response
     * @return
     */
    public static Result createCloudServerXls(JSONArray jsonArray, HttpServletRequest request, HttpServletResponse response) {
        try {
            // 创建HSSFWorkbook
            String sheetName = "报表导出";
            //表头，根据自己需求更改
            String[] cellTitle = new String[]{"学号","姓名","年龄","班级"};
            String[][] rows = null;
            List<Student> list = JSONArray.parseArray(jsonArray.toJSONString(), Student.class);
            if (!ListTool.isEmpty(list)) {
                rows = new String[list.size()][4];
                for (int i = 0; i < list.size(); i++) {
                    Student student = list.get(i);
                    rows[i][0] = student.getSno();
                    rows[i][1] = student.getName();
                    rows[i][2] = student.getAge();
                    rows[i][3] = student.getGrade()
                }
            } else {
                rows = new String[0][4];
            }
            HSSFWorkbook workbook = getHSSFWorkbook(sheetName, cellTitle, rows, null);
            // 下载表格到浏览器
            response.setCharacterEncoding("utf-8");
            response.setContentType("application/octet-stream");
            String fileName = sheetName + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + ".xls";
            final String userAgent = request.getHeader("user-agent").toLowerCase();
            if (userAgent.contains("trident") || userAgent.contains("edge")) {
                fileName = URLEncoder.encode(fileName, "UTF-8");
            } else {
                fileName = new String(fileName.getBytes("utf-8"), "iso-8859-1");
            }
            response.setHeader("Content-Disposition", "attachment;fileName=" + fileName);
            OutputStream os = response.getOutputStream();
            workbook.write(os);
            os.flush();
            os.close();
        } catch (Exception e) {
            logger.error("生成文档失败", e);
            return new Result(false, "发生异常生成文档失败");
        }
        return new Result(true, "生成文档成功");
    }

    /**
     * 导出Excel
     *
     * @param sheetName sheet名称
     * @param title     标题
     * @param values    内容
     * @param wb        HSSFWorkbook对象
     * @return
     */
    private static HSSFWorkbook getHSSFWorkbook(String sheetName, String[] title, String[][] values, HSSFWorkbook wb) {
        // 第一步，创建一个HSSFWorkbook，对应一个Excel文件
        if (wb == null) {
            wb = new HSSFWorkbook();
        }
        // 第二步，在workbook中添加一个sheet,对应Excel文件中的sheet
        HSSFSheet sheet = wb.createSheet(sheetName);
        // 第三步，在sheet中添加表头第0行,注意老版本poi对Excel的行数列数有限制
        HSSFRow row = sheet.createRow(0);
        // 第四步，创建单元格，并设置值表头 设置表头居中
        HSSFCellStyle style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.CENTER); // 创建一个居中格式
        // 声明列对象
        HSSFCell cell = null;
        // 创建标题
        for (int i = 0; i < title.length; i++) {
            cell = row.createCell(i);
            cell.setCellValue(title[i]);
            cell.setCellStyle(style);
        }
        // 创建内容
        for (int i = 0; i < values.length; i++) {
            row = sheet.createRow(i + 1);
            for (int j = 0; j < values[i].length; j++) {
                // 将内容按顺序赋给对应的列对象
                row.createCell(j).setCellValue(values[i][j]);
            }
        }
        return wb;
    }
}