上传读取Excel文件内容并入库

需求：读取前端上传的Excel，将数据入库，本工具类仅读取文件内容，不涉及到入库。当然，既然已经拿到了数据，那入库轻而易举。

package com.xx.utils;

import lombok.extern.slf4j.Slf4j;
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.io.InputStream;
import java.text.DecimalFormat;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;


/**
 * Description:excel相关工具类
 * 作者：Marco.Gu
 */
@Slf4j
public class ExcelUtils {

    /**
     * Description:读取excel文件
     * 作者：Marco.Gu
     * date:2019/11/11 9:24
     * @param file //文件
     * @param startrow //开始行号
     * @param startcol //开始列号
     * @param sheetnum //sheet
     * @return list
     */


    public static List> readExcel(MultipartFile file, int startrow, int startcol, int sheetnum) throws IOException {
        List> resultList = new LinkedList<>();
        try (InputStream fi = file.getInputStream();) {
            String fileName = file.getOriginalFilename();
            //进行版本选择解析方式
            Workbook wb = null;
            if (fileName.endsWith(".xlsx")) {
                wb = new XSSFWorkbook(fi);
            } else if (fileName.endsWith(".xls")) {
                wb = new HSSFWorkbook(fi);
            } else {
                log.error("文件非EXCEL");
                return null;
            }
            Sheet sheet = wb.getSheetAt(sheetnum);
            int rowNum = sheet.getLastRowNum() + 1;
            for (int i = startrow; i < rowNum; i++) {
                Map resultMap = new LinkedHashMap<>();
                Row row = sheet.getRow(i);
                //每行的最后一个单元格位置
                int cellNum = row.getLastCellNum();
                //列循环开始
                for (int j = startcol; j < cellNum; j++) {
                    Cell cell = row.getCell(j);
                    String cellValue = null;
                    if (null != cell) {
                        CellType cellTypeEnum = cell.getCellTypeEnum();
                        // 判断excel单元格内容的格式，并对其进行转换，以便插入数据库
                        switch (cellTypeEnum) {
                            case NUMERIC:
                                DecimalFormat format = new DecimalFormat("#");
                                cellValue = format.format(cell.getNumericCellValue());
                                break;
                            case STRING:
                                cellValue = cell.getStringCellValue();
                                break;
                            case FORMULA:
                                cellValue = cell.getCellFormula() + "";
                                break;
                            case _NONE:
                                cellValue = "";
                                break;
                            case BOOLEAN:
                                cellValue = String.valueOf(cell.getBooleanCellValue());
                                break;
                            case ERROR:
                                cellValue = String.valueOf(cell.getErrorCellValue());
                                break;
                        }
                    } else {
                        cellValue = "";
                    }
                    String key = sheet.getRow(0).getCell(j).getStringCellValue();
                    resultMap.put(key, cellValue);
                }
                resultList.add(resultMap);
            }
        } catch (IOException e) {
            log.error("EXCEL读取异常", e);
            throw e;
        }
        return resultList;
    }
}