Java读取Excel内容，最后获得一个list对象

代码层

public R importPackage(MultipartFile multipartFile) {
        try {
            log.info("multipartFile = " + multipartFile);
            log.info("ContentType = " + multipartFile.getContentType());
            log.info("OriginalFilename = " + multipartFile.getOriginalFilename());
            log.info("Name = " + multipartFile.getName());
            log.info("Size = " + multipartFile.getSize());
            //这里就是读取Excel中的数据
            List<PackageExcel> mlist = ExcelImportUtil.readExcel(PackageExcel.class, multipartFile);
            //这里就是根据文件名读取sheet页的名称，拿到我们想要的sheet页的数据
            String fileName = multipartFile.getOriginalFilename();
             InputStream is = multipartFile.getInputStream();
            Workbook workbook = null;
            if (fileName.endsWith("xlsx")) {
                workbook = new XSSFWorkbook(is);
            }
            if (fileName.endsWith("xls")) {
                workbook = new HSSFWorkbook(is);
            }
            //获取sheet页的名称
            String name = workbook.getSheetName(0);
            List<PackageExcel> mlists = mlist.stream().map(f -> f.setUnitName(name)).collect(Collectors.toList());
           
        } catch (Exception e) {
            log.error("导入包模版失败！", e);
            throw new RuntimeException(e.getMessage());
        }
    }

ExcelImportUtil工具类

package com.cloud.disinfectsupply.util;

import com.baomidou.mybatisplus.core.toolkit.CollectionUtils;
import com.ft.disinfectsupply.excel.ExcelColumn;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang3.BooleanUtils;
import org.apache.commons.lang3.CharUtils;
import org.apache.commons.lang3.math.NumberUtils;
import org.apache.poi.hssf.usermodel.HSSFDateUtil;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.http.MediaType;
import org.springframework.util.Assert;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;
import java.util.stream.Stream;

@Slf4j
public class ExcelImportUtil {

    private final static String EXCEL2003 = "xls";
    private final static String EXCEL2007 = "xlsx";

    public static <T> List<T> readExcel(Class<T> cls, MultipartFile file){

        String fileName = file.getOriginalFilename();
        if (!fileName.matches("^.+\\.(?i)(xls)$") && !fileName.matches("^.+\\.(?i)(xlsx)$")) {
            log.error("上传文件格式不正确");
            Assert.isTrue(false, "上传文件格式不正确");
        }
        List<T> dataList = new ArrayList<>();
        Workbook workbook = null;
        try {
            InputStream is = file.getInputStream();
            if (fileName.endsWith(EXCEL2007)) {
//                FileInputStream is = new FileInputStream(new File(path));
                workbook = new XSSFWorkbook(is);
            }
            if (fileName.endsWith(EXCEL2003)) {
//                FileInputStream is = new FileInputStream(new File(path));
                workbook = new HSSFWorkbook(is);
            }
            if (workbook != null) {
                //类映射  注解 value-->bean columns
                Map<String, List<Field>> classMap = new HashMap<>();
                List<Field> fields = Stream.of(cls.getDeclaredFields()).collect(Collectors.toList());
                fields.forEach(
                        field -> {
                            ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                            if (annotation != null) {
                                String value = annotation.value().trim();
                                if (StringUtils.isBlank(value)) {
                                    return;//return起到的作用和continue是相同的 语法
                                }
                                if (!classMap.containsKey(value)) {
                                    classMap.put(value, new ArrayList<>());
                                }
                                field.setAccessible(true);
                                classMap.get(value).add(field);
                            }
                        }
                );
                //索引-->columns
                Map<Integer, List<Field>> reflectionMap = new HashMap<>(16);
                //默认读取第一个sheet
                Sheet sheet = workbook.getSheetAt(0);
                Row _firstRow = null;
                boolean firstRow = true;
                for (int i = sheet.getFirstRowNum(); i <= sheet.getLastRowNum(); i++) {
                    Row row = sheet.getRow(i);
                    //首行  提取注解
                    if (firstRow) {
                        _firstRow = row;
                        for (int j = row.getFirstCellNum(); j <= row.getLastCellNum(); j++) {
                            Cell cell = row.getCell(j);
                            String cellValue = getCellValue(cell);
                            if (classMap.containsKey(cellValue)) {
                                reflectionMap.put(j, classMap.get(cellValue));
                            }
                        }
                        firstRow = false;
                    } else {
                        //忽略空白行
                        if (row == null) {
                            continue;
                        }
                        try {
                            T t = cls.newInstance();
                            //判断是否为空白行
                            boolean allBlank = true;
                            for (int j = row.getFirstCellNum(); j <= row.getLastCellNum(); j++) {
                                Cell cell = row.getCell(j);
                                String cellValue = getCellValue(cell);
                                if (reflectionMap.containsKey(j)) {

                                    if (StringUtils.isNotBlank(cellValue)) {
                                        allBlank = false;
                                    }
                                    List<Field> fieldList = reflectionMap.get(j);
                                    fieldList.forEach(
                                            x -> {
                                                try {
                                                    handleField(t, cellValue, x);
                                                } catch (Exception e) {
                                                    log.error(String.format("reflect field:%s value:%s exception!", x.getName(), cellValue), e);
                                                }
                                            }
                                    );
                                } else {
                                    /*if(t instanceof ImportMonResVo) {
                                        String title = getCellValue( _firstRow.getCell(j));
                                        if(!StringHelper.isEmpty(title)) {
                                            MonTypeDefAttr monTypeDefAttr = new MonTypeDefAttr();
                                            monTypeDefAttr.setCnName(title);
                                            monTypeDefAttr.setValue(cellValue);
                                            ((ImportMonResVo)t).getExAttrs().add(monTypeDefAttr);
                                        }
                                    }*/
                                }
                            }
                            if (!allBlank) {
                                dataList.add(t);
                            } else {
                                log.warn(String.format("row:%s is blank ignore!", i));
                            }
                        } catch (Exception e) {
                            log.error(String.format("parse row:%s exception!", i), e);
                        }
                    }
                }
            }
        } catch (Exception e) {
            log.error(String.format("parse excel exception!"), e);
        } finally {
            if (workbook != null) {
                try {
                    workbook.close();
                } catch (Exception e) {
                    log.error(String.format("parse excel exception!"), e);
                }
            }
        }
        return dataList;
    }

    private static <T> void handleField(T t, String value, Field field) throws Exception {
        Class<?> type = field.getType();
        if (type == null || type == void.class || StringUtils.isBlank(value)) {
            return;
        }
        if (type == Object.class) {
            field.set(t, value);
            //数字类型
        } else if (type.getSuperclass() == null || type.getSuperclass() == Number.class) {
            if (type == int.class || type == Integer.class) {
                field.set(t, NumberUtils.toInt(value));
            } else if (type == long.class || type == Long.class) {
                field.set(t, NumberUtils.toLong(value));
            } else if (type == byte.class || type == Byte.class) {
                field.set(t, NumberUtils.toByte(value));
            } else if (type == short.class || type == Short.class) {
                field.set(t, NumberUtils.toShort(value));
            } else if (type == double.class || type == Double.class) {
                field.set(t, NumberUtils.toDouble(value));
            } else if (type == float.class || type == Float.class) {
                field.set(t, NumberUtils.toFloat(value));
            } else if (type == char.class || type == Character.class) {
                field.set(t, CharUtils.toChar(value));
            } else if (type == boolean.class) {
                field.set(t, BooleanUtils.toBoolean(value));
            } else if (type == BigDecimal.class) {
                field.set(t, new BigDecimal(value));
            }
        } else if (type == Boolean.class) {
            field.set(t, BooleanUtils.toBoolean(value));
        } else if (type == Date.class) {
            //
            field.set(t, value);
        } else if (type == String.class) {
            field.set(t, value);
        } else {
            Constructor<?> constructor = type.getConstructor(String.class);
            field.set(t, constructor.newInstance(value));
        }
    }

    private static String getCellValue(Cell cell) {
        if (cell == null) {
            return "";
        }

        if (cell.getCellType() == CellType.NUMERIC) {
            if (HSSFDateUtil.isCellDateFormatted(cell)) {
                return HSSFDateUtil.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();
        }

    }

    public static <T> void writeExcel(HttpServletResponse response, List<T> dataList, Class<T> cls,String filePath){
        Field[] fields = cls.getDeclaredFields();
        List<Field> fieldList = Arrays.stream(fields)
                .filter(field -> {
                    ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                    if (annotation != null) {
                        field.setAccessible(true);
                        return true;
                    }
                    return false;
                }).collect(Collectors.toList());

        Workbook wb = new XSSFWorkbook();
        Sheet sheet = wb.createSheet("Sheet1");
        AtomicInteger ai = new AtomicInteger();
        {
            Row row = sheet.createRow(ai.getAndIncrement());
            AtomicInteger aj = new AtomicInteger();
            //写入头部
            fieldList.forEach(field -> {
                ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                String columnName = "";
                if (annotation != null) {
                    columnName = annotation.value();
                }
                Cell cell = row.createCell(aj.getAndIncrement());

                CellStyle cellStyle = wb.createCellStyle();
                cellStyle.setFillForegroundColor(IndexedColors.WHITE.getIndex());
                cellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
                cellStyle.setAlignment(HorizontalAlignment.CENTER);

                Font font = wb.createFont();
                font.setFontHeightInPoints((short)14);
                cellStyle.setFont(font);
                cell.setCellStyle(cellStyle);
                cell.setCellValue(columnName);
            });
        }
        if (CollectionUtils.isNotEmpty(dataList)) {
            dataList.forEach(t -> {
                Row row1 = sheet.createRow(ai.getAndIncrement());
                AtomicInteger aj = new AtomicInteger();
                fieldList.forEach(field -> {
                    Class<?> type = field.getType();
                    Object value = "";
                    try {
                        value = field.get(t);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                    Cell cell = row1.createCell(aj.getAndIncrement());
                    if (value != null) {
                        if (type == Date.class) {
                            cell.setCellValue(value.toString());
                        } else {
                            cell.setCellValue(value.toString());
                        }
                        cell.setCellValue(value.toString());
                    }
                });
            });
        }
        //冻结窗格
        wb.getSheet("Sheet1").createFreezePane(0, 1, 0, 1);
        //浏览器下载excel
        //buildExcelDocument("abbot.xlsx",wb,response);
        //生成excel文件
        //buildExcelFile("d:/default.xlsx",wb);

        buildExcelFile(safeToString(filePath,"d:/default.xlsx"),wb);
    }

    public static <T> void writeExcel(HttpServletResponse response, List<T> dataList, Class<T> cls){
        writeExcel(response,  dataList, cls,"");
    }

    public static <T> void writeExcelByPage(HttpServletResponse response, List<T> dataList, Class<T> cls, Workbook wb, String sheetName){
        Field[] fields = cls.getDeclaredFields();
        List<Field> fieldList = Arrays.stream(fields)
                .filter(field -> {
                    ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                    if (annotation != null) {
                        field.setAccessible(true);
                        return true;
                    }
                    return false;
                }).collect(Collectors.toList());
        Sheet sheet = wb.createSheet(sheetName);
        AtomicInteger ai = new AtomicInteger();
        {
            Row row = sheet.createRow(ai.getAndIncrement());
            AtomicInteger aj = new AtomicInteger();
            //写入头部
            fieldList.forEach(field -> {
                ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                String columnName = "";
                if (annotation != null) {
                    columnName = annotation.value();
                }
                Cell cell = row.createCell(aj.getAndIncrement());

                CellStyle cellStyle = wb.createCellStyle();
                cellStyle.setFillForegroundColor(IndexedColors.WHITE.getIndex());
                cellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
                cellStyle.setAlignment(HorizontalAlignment.CENTER);

                Font font = wb.createFont();
//                font.setBoldweight(Font.BOLDWEIGHT_NORMAL);
                font.setFontHeightInPoints((short)14);
                cellStyle.setFont(font);
                cell.setCellStyle(cellStyle);
                cell.setCellValue(columnName);
            });
        }
        if (CollectionUtils.isNotEmpty(dataList)) {
            dataList.forEach(t -> {
                Row row1 = sheet.createRow(ai.getAndIncrement());
                AtomicInteger aj = new AtomicInteger();
                fieldList.forEach(field -> {
                    Class<?> type = field.getType();
                    Object value = "";
                    try {
                        value = field.get(t);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                    Cell cell = row1.createCell(aj.getAndIncrement());
                    if (value != null) {
                        if (type == Date.class) {
                            cell.setCellValue(value.toString());
                        } else {
                            cell.setCellValue(value.toString());
                        }
                        cell.setCellValue(value.toString());
                    }
                });
            });
        }
        //冻结窗格
        wb.getSheet(sheetName).createFreezePane(0, 1, 0, 1);
        //浏览器下载excel
        //buildExcelDocument("abbot.xlsx",wb,response);
        //生成excel文件
    }

    /**
     * 浏览器下载excel
     * @param fileName
     * @param wb
     * @param response
     */

    public static  void  buildExcelDocument(String fileName, Workbook wb, HttpServletResponse response){
        try {
            response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
            response.setHeader("Content-Disposition", "attachment;filename="+ URLEncoder.encode(fileName, "utf-8"));
            response.setHeader("FileNames", UUID.randomUUID().toString() +".xls");
            response.setHeader("Access-Control-Expose-Headers", "FileNames");
            response.flushBuffer();
            wb.write(response.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 生成excel文件
     * @param path 生成excel路径
     * @param wb
     */
    public static  void  buildExcelFile(String path, Workbook wb)  {

        File file = new File(path);
        if(!file.getParentFile().exists()){
            file.getParentFile().mkdirs();
        }
        if (file.exists()) {
            file.delete();
        }
        FileOutputStream fileOutputStream=null;
        try {
            fileOutputStream=new FileOutputStream(file);
            wb.write(fileOutputStream);
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            if(fileOutputStream!=null){
                try {
                    fileOutputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }


    public static String safeToString(Object obj, String def) {
        if (null != obj && !"".equals(obj.toString()) && !"null".equals(obj.toString())) {
            def = obj.toString();
        }
        return def;
    }

}

PackageExcel实体类

package com.ft.disinfectsupply.excel;

import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.annotation.write.style.ColumnWidth;
import com.alibaba.excel.annotation.write.style.ContentStyle;
import com.alibaba.excel.annotation.write.style.HeadRowHeight;
import com.alibaba.excel.annotation.write.style.HeadStyle;
import com.alibaba.excel.enums.poi.HorizontalAlignmentEnum;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
import lombok.experimental.Accessors;

import java.io.Serializable;
import java.util.List;

/**
 * @Author caozhenbang
 * @Date: 2023-07-12
 * @Description
 */
@Data
@Accessors(chain = true)
@ApiModel(value = "包模板", description = "包模板")
public class PackageExcel implements Serializable {

    @ApiModelProperty("科室名称" )
    @ExcelColumn("科室")//这个就是Excel里面的表头的名字
    private String deptName;

    @ApiModelProperty("包名称" )
    @ExcelColumn("包名称")
    private String packageName;

    @ApiModelProperty("包总数" )
    @ExcelColumn("包总数")
    private int packageCount;

    @ApiModelProperty("包装材料" )
    @ExcelColumn("包装材料(棉布，纸朔等等)")
    private String packageMaterial;


    @ApiModelProperty("器械" )
    @ExcelColumn("单个包的器械名称")
    private String instrument;


    @ApiModelProperty("器械数量" )
    @ExcelColumn("器械数量")
    private int instrumentCount;

    @ApiModelProperty("器械规格" )
    @ExcelColumn("器械规格(选填)")
    private String instrumentSpecification;


}

Excel样式

Excel表头的字要和实体类中@ExcelColumn对应上，这样才会读取