用poi从excel文档导入数据

import org.apache.commons.lang3.StringUtils;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;
import java.math.BigDecimal;
import java.util.*;

public class ImportExcelTool {
    public static List<Map<String, String>> readExcel(MultipartFile file) throws IOException {
        Workbook workbook = null;
        String fileName = file.getOriginalFilename();
        if (Objects.requireNonNull(fileName).endsWith(".xlsx"))
            workbook = new XSSFWorkbook(file.getInputStream());
        if (fileName.endsWith(".xls"))
            workbook = new HSSFWorkbook(file.getInputStream());
        Sheet sheet = Objects.requireNonNull(workbook).getSheetAt(0);
        int physicalNumberOfRows = sheet.getPhysicalNumberOfRows();

        Row row = sheet.getRow(1);
        List<String> fieldNames = new ArrayList<>();
        for (int i = 0; i < row.getLastCellNum(); i++)
            fieldNames.add(row.getCell(i).getRichStringCellValue().getString());

        List<Map<String, String>> lsMap = new ArrayList<>();

        for (int j = 3; j < physicalNumberOfRows; j++) {
            Map<String, String> dataMap = new HashMap<>();
            Row dataRow = sheet.getRow(j);
            if (dataRow == null)
                break;
            for (int i = 0; i < dataRow.getLastCellNum(); i++) {
                String val = getCellValue(dataRow.getCell(i));
                dataMap.put(fieldNames.get(i), val);
            }
            if (dataMap.size() == 0)
                break;

            lsMap.add(dataMap);
        }
        return lsMap;
    }


    private static String getCellValue(Cell cell) {
        if (cell == null)
            return "";
        if (cell.getCellType() == CellType.NUMERIC)
            if (DateUtil.isCellDateFormatted(cell))
                return DateUtil.getJavaDate(cell.getNumericCellValue()).toString();
            else
                return new BigDecimal(cell.getNumericCellValue()).toString();
        else if (cell.getCellType() == CellType.STRING)
            return StringUtils.trimToEmpty(cell.getStringCellValue());
        else if (cell.getCellType() == CellType.FORMULA)
            return StringUtils.trimToEmpty(cell.getCellFormula());
        else if (cell.getCellType() == CellType.BLANK)
            return "";
        else if (cell.getCellType() == CellType.BOOLEAN)
            return String.valueOf(cell.getBooleanCellValue());
        else if (cell.getCellType() == CellType.ERROR)
            return "ERROR";
        else
            return cell.toString().trim();

    }
}