4dkankan-center-manage/src/main/java/com/fdkankan/manage/util/ExcelUtil.java

package com.fdkankan.manage.util;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class ExcelUtil {


    public static List<HashMap<Integer,String>> getExcelRowList(MultipartFile multipartFile) throws IOException {
        //行List,也是最终要返回的List
        List<HashMap<Integer,String>> rowList=new ArrayList<>();
        Workbook workbook=getExcelWorkBook(multipartFile);
        Sheet sheet = workbook.getSheetAt(0);
        if (sheet == null) {
            throw new IOException("创建Sheet失败！");
        }
        //开始遍历行
        for (int i=3;i<= sheet.getLastRowNum();i++){
            Row row = sheet.getRow(i);
            //列List
            HashMap<Integer,String> map = new HashMap<>();
            //转换为List数组
            for (int cellNum=0;cellNum<= row.getLastCellNum();cellNum++){
                Cell cell = row.getCell(cellNum);
                if(cell != null){
                    map.put(cellNum,cell.toString().trim());
                }
            }
            rowList.add(map);
        }
        workbook.close();
        return rowList;
    }


    //获取WorkBook对象
    private static Workbook getExcelWorkBook(MultipartFile multipartFile) throws IOException {
        InputStream inputStream=multipartFile.getInputStream();
        String originalFileName=multipartFile.getOriginalFilename();
        assert originalFileName != null;
        String fileType=originalFileName.substring(originalFileName.lastIndexOf(".")+1);
        if (fileType.equalsIgnoreCase("xls")) {
            //xls格式
            return new HSSFWorkbook(inputStream);
        } else {
            //xlsx格式
            return new XSSFWorkbook(inputStream);
        }
    }
}