Springboot实现导入导出Excel的方法

目录

• 一、添加poi的maven依赖
• 二、自定义注解(Excel属性标题、位置等)
• 三、CustomExcelUtils编写
• 四、定义导出实体类
• 五、Controller层代码编写

一、添加poi的maven依赖

    org.apache.poi
    poi
    3.13


    org.apache.poi
    poi-ooxml
    3.13

二、自定义注解(Excel属性标题、位置等)

package com.cloud.core.annotation;

import java.lang.annotation.*;

/**
 * 自定义实体类所需要的bean(Excel属性标题、位置等)
 * Copyright: Copyright (C) 2021 DLANGEL, Inc. All rights reserved.
 * Company: 大连安琪科技有限公司
 *
 * @author Rex
 * @since 2021/5/19 9:30
 */
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ExcelColumn {
    /**
     * Excel标题
     *
     * @return
     * @author Rex
     */
    String value() default "";

    /**
     * Excel从左往右排列位置，第一个是0
     *
     * @return
     * @author Rex
     */
    int col() default 0;
}

三、CustomExcelUtils编写

package com.cloud.core.utils;

import com.baomidou.mybatisplus.core.toolkit.CollectionUtils;
import com.cloud.core.annotation.ExcelColumn;
import com.cloud.core.common.CommonConst;
import org.apache.commons.lang.BooleanUtils;
import org.apache.commons.lang.CharUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.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.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.MediaType;
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;

/**
 * 自定义导入导出Excel文件类
 * Copyright: Copyright (C) 2021 DLANGEL, Inc. All rights reserved.
 * Company: 大连安琪科技有限公司
 *
 * @author Rex
 * @since 2021/5/19 9:31
 */
public class CustomExcelUtils {
    private final static Logger log = LoggerFactory.getLogger(CustomExcelUtils.class);

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

    /**
     * 读取Excel
     *
     * @param path     为了测试文件用，实际为空
     * @param cls      类
     * @param startRow 起始行
     * @param file     文件
     * @return
     * @author Rex
     */
    public static  List readExcel(String path, Class cls, int startRow, MultipartFile file) {

        String fileName = file.getOriginalFilename();
        if (!fileName.matches(CommonConst.Regex.FILE_EXT_XLS) && !fileName.matches(CommonConst.Regex.FILE_EXT_XLSX)) {
            log.error("上传文件格式不正确");
        }
        List 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> classMap = new HashMap<>();
                List fields = Stream.of(cls.getDeclaredFields()).collect(Collectors.toList());
                fields.forEach(
                        field -> {
                            ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                            if (annotation != null) {
                                String value = annotation.value();
                                if (StringUtils.isBlank(value)) {
                                    // return起到的作用和continue是相同的 语法
                                    return;
                                }
                                if (!classMap.containsKey(value)) {
                                    classMap.put(value, new ArrayList<>());
                                }
                                field.setAccessible(true);
                                classMap.get(value).add(field);
                            }
                        }
                );
                //索引-->columns
                Map> reflectionMap = new HashMap<>(16);
                //默认读取第一个sheet
                Sheet sheet = workbook.getSheetAt(0);

                boolean firstRow = true;
                for (int i = startRow; i <= sheet.getLastRowNum(); i++) {
                    Row row = sheet.getRow(i);
                    // 提取注解
                    if (firstRow) {
                        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));
                            }
                        }
                        if (reflectionMap.size() > 0) {
                            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++) {
                                if (reflectionMap.containsKey(j)) {
                                    Cell cell = row.getCell(j);
                                    String cellValue = getCellValue(cell);
                                    if (StringUtils.isNotBlank(cellValue)) {
                                        allBlank = false;
                                    }
                                    List 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);
                                                }
                                            }
                                    );
                                }
                            }
                            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  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() == Cell.CELL_TYPE_NUMERIC) {
            if (HSSFDateUtil.isCellDateFormatted(cell)) {
                return HSSFDateUtil.getJavaDate(cell.getNumericCellValue()).toString();
            } else {
                return new BigDecimal(cell.getNumericCellValue()).toString();
            }
        } else if (cell.getCellType() == Cell.CELL_TYPE_STRING) {
            return StringUtils.trimToEmpty(cell.getStringCellValue());
        } else if (cell.getCellType() == Cell.CELL_TYPE_FORMULA) {
            return StringUtils.trimToEmpty(cell.getCellFormula());
        } else if (cell.getCellType() == Cell.CELL_TYPE_BLANK) {
            return "";
        } else if (cell.getCellType() == Cell.CELL_TYPE_BOOLEAN) {
            return String.valueOf(cell.getBooleanCellValue());
        } else if (cell.getCellType() == Cell.CELL_TYPE_ERROR) {
            return "ERROR";
        } else {
            return cell.toString().trim();
        }

    }

    public static  void writeExcel(HttpServletResponse response, List dataList, Class cls) {
        Field[] fields = cls.getDeclaredFields();
        List fieldList = Arrays.stream(fields)
                .filter(field -> {
                    ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                    if (annotation != null && annotation.col() > 0) {
                        field.setAccessible(true);
                        return true;
                    }
                    return false;
                }).sorted(Comparator.comparing(field -> {
                    int col = 0;
                    ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                    if (annotation != null) {
                        col = annotation.col();
                    }
                    return col;
                })).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(CellStyle.SOLID_FOREGROUND);
                cellStyle.setAlignment(CellStyle.ALIGN_CENTER);

                Font font = wb.createFont();
                font.setBoldweight(Font.BOLDWEIGHT_NORMAL);
                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("导出数据.xlsx", wb, response);
        //生成excel文件
//        buildExcelFile(".\\default.xlsx", wb);
    }

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

    private 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.flushBuffer();
            wb.write(response.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

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

        File file = new File(path);
        if (file.exists()) {
            file.delete();
        }
        try {
            wb.write(new FileOutputStream(file));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

四、定义导出实体类

主要是使用这里的@ExcelColumn注解，其中的col从0开始的。

package com.cloud.library.model.role;

import com.cloud.core.annotation.ExcelColumn;
import lombok.Data;

/**
 * 导入角色用
 * Copyright: Copyright (C) 2021 DLANGEL, Inc. All rights reserved.
 * Company: 大连安琪科技有限公司
 *
 * @author Rex
 * @since 2021/5/19 16:13
 */
@Data
public class SysRoleExcel {
    @ExcelColumn(value = "姓名", col = 1)
    private String name;
    @ExcelColumn(value = "描述", col = 2)
    private String description;
}

Excel对应的模板参考

五、Controller层代码编写

//region 导入数据

    /**
     * 导入数据
     *
     * @param file
     * @return
     * @author Rex
     */
    @RequestMapping(value = "/readExcel", method = RequestMethod.POST)
    public void readExcel(@RequestParam(value = "uploadFile", required = false) MultipartFile file) {
        List list = CustomExcelUtils.readExcel("", SysRoleExcel.class, 0, file);
        List sysRoleList = new ArrayList<>();
        list.forEach(e -> {
            SysRole sysRole = new SysRole();
            BeanUtils.copyProperties(e, sysRole);
            sysRoleList.add(sysRole);
        });
        sysRoleService.saveBatch(sysRoleList);
    }
    // endregion

这里发现了，这个saveBatch可以直接使用雪花的id来保存数据，因为这里用的是mybatis-plus，单条数据保存使用的是它的配置。然后试了下，批量导入也是可以的，另外，这个批量保存，理论上没有条数限制，这个还等待后续测试。

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