SpringBoot操作excel文件【工具类】

public class AnalysisExcelDataUtil {
    /**
     *
     * @param file 上传的excel文件
     * @return
     * @throws IOException
     */
    public static List<List> getExcelData(MultipartFile file, boolean readFirstRow) throws IOException {
        checkFile(file);
        //获得Workbook工作薄对象
        Workbook workbook = getWorkBook(file);
        //创建返回对象，把每行中的值作为一个数组，所有行作为一个集合返回
        List<List> list = new ArrayList<>();
        if (workbook != null) {
            for (int sheetNum = 0; sheetNum < workbook.getNumberOfSheets(); sheetNum++) {
                //获得当前sheet工作表
                Sheet sheet = workbook.getSheetAt(sheetNum);
                if (sheet == null) {
                    continue;
                }
                //获得当前sheet的开始行
                int firstRowNum = sheet.getFirstRowNum();
                //获得当前sheet的结束行
                int lastRowNum = sheet.getLastRowNum();
                //循环除了所有行,如果要循环除第一行以外的就firstRowNum+1
                for (int rowNum = (readFirstRow ? firstRowNum : firstRowNum + 1); rowNum <= lastRowNum; rowNum++) {
                    //获得当前行
                    Row row = sheet.getRow(rowNum);
                    if (row == null) {
                        continue;
                    }
                    //获得当前行的开始列
                    int firstCellNum = row.getFirstCellNum();
                    //获得当前行的列数
                    int lastCellNum = row.getLastCellNum();
                    if (lastCellNum > 0) {
                        ArrayList<Object> cellValues = new ArrayList<>();
                        //循环当前行
                        for (int cellNum = firstCellNum; cellNum < lastCellNum; cellNum++) {
                            Cell cell = row.getCell(cellNum);
                            cellValues.add(getCellValue(cell));
                        }
                        list.add(cellValues);
                    }
                }
            }
        }
        return list;
    }
    /**
     * 检查文件
     *
     * @param file
     * @throws IOException
     */
    public static void checkFile(MultipartFile file) throws IOException {
        //判断文件是否存在
        if (null == file) {
            System.err.println("文件不存在！");
        }
        //获得文件名
        String fileName = file.getOriginalFilename();
        //判断文件是否是excel文件
        if (!fileName.endsWith("xls") && !fileName.endsWith("xlsx")) {
            System.err.println("不是excel文件");
        }
    }
    public static Workbook getWorkBook(MultipartFile file) {
        //获得文件名
        String fileName = file.getOriginalFilename();
        //创建Workbook工作薄对象，表示整个excel
        Workbook workbook = null;
        try {
            //获取excel文件的io流
            InputStream is = file.getInputStream();
            //根据文件后缀名不同(xls和xlsx)获得不同的Workbook实现类对象
            if (fileName.endsWith("xls")) {
                //2003
                workbook = new HSSFWorkbook(is);
            } else if (fileName.endsWith("xlsx")) {
                //2007 及2007以上
                workbook = new XSSFWorkbook(is);
            }
        } catch (IOException e) {
            e.getMessage();
        }
        return workbook;
    }
    public static String getCellValue(Cell cell) {
        String cellValue = "";
        if (cell == null) {
            return cellValue;
        }
        //判断数据的类型
        switch (cell.getCellTypeEnum()) {
            //数字
            case NUMERIC:
                cellValue = stringDateProcess(cell);
                break;
            //字符串
            case STRING:
                cellValue = String.valueOf(cell.getStringCellValue());
                break;
            //Boolean
            case BOOLEAN:
                cellValue = String.valueOf(cell.getBooleanCellValue());
                break;
            //公式
            case FORMULA:
                cellValue = String.valueOf(cell.getCellFormula());
                break;
            //空值
            case BLANK:
                cellValue = "";
                break;
            //故障
            case ERROR:
                cellValue = "非法字符";
                break;
            default:
                cellValue = "未知类型";
                break;
        }
        return cellValue;
    }
    public static String stringDateProcess(Cell cell) {
        String result = new String();
        // 处理日期格式、时间格式
        if (HSSFDateUtil.isCellDateFormatted(cell)) {
            SimpleDateFormat sdf = null;
            if (cell.getCellStyle().getDataFormat() == HSSFDataFormat.getBuiltinFormat("h:mm")) {
                sdf = new SimpleDateFormat("HH:mm");
            } else {
                // 日期
                sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
            }
            Date date = cell.getDateCellValue();
            result = sdf.format(date);
        } else if (cell.getCellStyle().getDataFormat() == 58) {
            // 处理自定义日期格式：m月d日(通过判断单元格的格式id解决，id的值是58)
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
            double value = cell.getNumericCellValue();
            Date date = org.apache.poi.ss.usermodel.DateUtil
                .getJavaDate(value);
            result = sdf.format(date);
        } else {
            double value = cell.getNumericCellValue();
            CellStyle style = cell.getCellStyle();
            DecimalFormat format = new DecimalFormat();
            String temp = style.getDataFormatString();
            // 单元格设置成常规
            if (temp.equals("General")) {
                format.applyPattern("#");
            }
            result = format.format(value);
        }
        return result;
    }
    public static InputStream convertorStream(Workbook workbook) {
        InputStream in = null;
        try {
            //临时缓冲区
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            //创建临时文件
            workbook.write(out);
            byte[] bookByteAry = out.toByteArray();
            in = new ByteArrayInputStream(bookByteAry);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return in;
    }
    /**
     * excel单元格数据转字符串
     * @param obj
     * @return
     */
    public static String cellDataToString(Object obj) {
        if (obj == null) {
            return "";
        }
        String objString = String.valueOf(obj);
        if (objString == null) {
            return "";
        }
        return objString.trim();
    }
}