Excel 导入、导出的封装

最近在封装公司统一使用的组件，主要目的是要求封装后开发人员调用简单，不用每个项目组中重复去集成同一个依赖l，写的五花八门，代码不规范，后者两行泪。

为此，我们对EasyExcel进行了二次封装，我会先来介绍下具体使用，然后再给出封装过程

环境准备
开发环境：SpringBoot+mybatis-plus+db

数据库：

-- `dfec-tcht-platform-dev`.test definition

CREATE TABLE `test` (
  `num` decimal(10,0) DEFAULT NULL COMMENT '数字',
  `sex` varchar(100) DEFAULT NULL COMMENT '性别',
  `name` varchar(100) DEFAULT NULL COMMENT '姓名',
  `born_date` datetime DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

使用
第一步、在接口类中引入以下

@Aurowired 
ExcelService excelService;

第二步、标注字段
这些个注解是EasyExcel的注解，我们做了保留，仍然使用他的注解

/**
 * 【请填写功能名称】对象 test
 *
 */
@Data
@TableName("test")
public class TestEntity  {

    /**
     * 数字
     */
    @Schema(description = "数字")
    @ExcelProperty("数字")
    private BigDecimal num;


    /**
     * 性别
     */
    @Schema(description = "性别")
    @ExcelProperty("性别")
    private String sex;


    /**
     * 姓名
     */
    @Schema(description = "姓名")
    @ExcelProperty("姓名")
    private String name;


    /**
     * 创建时间
     */
    @Schema(description = "创建时间")
    @ExcelProperty(value = "创建时间")
    private Date bornDate;

 
}

第三步、使用

@PostMapping("/importExcel")
public void importExcel(@RequestParam MultipartFile file){
   excelService.importExcel(file, TestEntity.class,2,testService::saveBatch);
}


@PostMapping("/exportExcel")
public void exportExcel(HttpServletResponse response) throws IOException {
   excelService.exportExcel(testService.list(),TestEntity.class,response);
} 

完整代码

/**
 * @title: TestController
 * @projectName df-platform
 * @description: TODO
 */

@RestController
@RequestMapping("test")
@RequiredArgsConstructor
public class TestController {


    private  final ExcelService excelService;

    private final TestService testService;


    @PostMapping("/importExcel")
    public void importExcel(@RequestParam MultipartFile file){
        excelService.importExcel(file, TestEntity.class,2,testService::saveBatch);
    }


    @PostMapping("/exportExcel")
    public void exportExcel(HttpServletResponse response) throws IOException {
        excelService.exportExcel(testService.list(),TestEntity.class,filePath,response);
    }


}

哈哈哈，是不是非常简洁

以上只是一个简单的使用情况，我们还封装了支持模板的导入、导出，数据转换等问题，客官请继续向下看。

如果遇到有读取到的数据和实际保存的数据不一致的情况下，可以使用如下方式导入，这里给出一个示例

@PostMapping("/importExcel")
public void importExcel(@RequestParam MultipartFile file){
    Function<TestEntity, TestVo> map = new Function<TestEntity, TestVo>() {
        @Override
        public TestVo apply(TestEntity testEntities) {
            TestVo testVo = new TestVo();
            testVo.setNum(testEntities.getNum());
            testVo.setSex(testEntities.getSex());
            testVo.setBaseName(testEntities.getName());
            return testVo;
        }
    };
    excelService.importExcel(file, TestEntity.class,2,map,testService::saveBatchTest);
}

封装过程

核心思想：

对导入和导出提供接口、保持最少依赖原则

我们先从ExcelService接口类出发，依次看下封装的几个核心类

/**
 * ExcelService
 *
 * @interfaceName ExcelService
 **/
public interface ExcelService {

    /**
     * 导出Excel，默认
     * @param list 导出的数据
     * @param tClass 带有excel注解的实体类
     * @param response 相应
     * @return T
     */
    <T> void exportExcel(List<T> list, Class<T> tClass, HttpServletResponse response) throws IOException;

    /**
     * 导出Excel，增加类型转换
     * @param list 导出的数据
     * @param tClass 带有excel注解的实体类
     * @param response 相应
     * @return T
     */
    <T, R> void exportExcel(List<T> list, Function<T, R> map, Class<R> tClass, HttpServletResponse response) throws IOException;


    /**
     * 导出Excel，按照模板导出，这里是填充模板
     * @param list 导出的数据
     * @param tClass 带有excel注解的实体类
     * @param template 模板
     * @param response 相应
     * @return T
     */
    <T> void exportExcel(List<T> list, Class<T> tClass, String template, HttpServletResponse response) throws IOException;

    /**
     * 导入Excel
     * @param file 文件
     * @param tClass 带有excel注解的实体类
     * @param headRowNumber 表格头行数据
     * @param map 类型转换
     * @param consumer 消费数据的操作
     * @return T
     */
    <T, R> void importExcel(MultipartFile file, Class<T> tClass, Integer headRowNumber, Function<T, R> map, Consumer<List<R>> consumer);


    /**
     * 导入Excel
     * @param file 文件
     * @param tClass 带有excel注解的实体类
     * @param headRowNumber 表格头行数据
     * @param consumer 消费数据的操作
     * @return T
     */
    <T> void importExcel(MultipartFile file, Class<T> tClass, Integer headRowNumber, Consumer<List<T>> consumer);

}

以上接口只有个导入、导出，只是加了几个重载方法而已

再看下具体的实现类

package com.dfec.framework.excel.service.impl;

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.support.ExcelTypeEnum;
import com.dfec.framework.excel.convert.LocalDateTimeConverter;
import com.dfec.framework.excel.service.ExcelService;
import com.dfec.framework.excel.util.ExcelUtils;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.List;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.stream.Collectors;

/**
 * DefaultExcelServiceImpl
 *
 * @className DefaultExcelServiceImpl
 **/
@Service
public class DefaultExcelServiceImpl implements ExcelService {

    @Override
    public <T> void exportExcel(List<T> list, Class<T> tClass, HttpServletResponse response) throws IOException {
        setResponse(response);
        EasyExcel.write(response.getOutputStream())
                .head(tClass)
                .excelType(ExcelTypeEnum.XLSX)
                .registerConverter(new LocalDateTimeConverter())
                .sheet("工作簿1")
                .doWrite(list);

    }

    @Override
    public <T, R> void exportExcel(List<T> list, Function<T, R> map, Class<R> tClass, HttpServletResponse response) throws IOException {
        setResponse(response);
        List<R> result = list.stream().map(map::apply).collect(Collectors.toList());
        exportExcel(result, tClass, response);
    }

    @Override
    public <T> void exportExcel(List<T> list, Class<T> tClass,String template, HttpServletResponse response) throws IOException {
        setResponse(response);
        EasyExcel.write(response.getOutputStream())
                .withTemplate(template)
                .excelType(ExcelTypeEnum.XLS)
                .useDefaultStyle(false)
                .registerConverter(new LocalDateTimeConverter())
                .sheet(0)
                .doFill(list) ;

    }

    @Override
    public <T,R> void importExcel(MultipartFile file, Class<T> tClass,Integer headRowNumber, Function<T, R> map,Consumer<List<R>> consumer) {
        List<T> excelData = ExcelUtils.readExcelData(file,tClass,headRowNumber);
        List<R> result = excelData.stream().map(map::apply).collect(Collectors.toList());
        consumer.accept(result);
    }

    @Override
    public <T> void importExcel(MultipartFile file, Class<T> tClass,Integer headRowNumber, Consumer<List<T>> consumer) {
        List<T> excelData = ExcelUtils.readExcelData(file,tClass,headRowNumber);
        consumer.accept(excelData);

    }


    public void setResponse(HttpServletResponse response) throws UnsupportedEncodingException {
        response.setContentType("application/vnd.ms-excel");
        response.setCharacterEncoding("utf-8");
        // 这里URLEncoder.encode可以防止中文乱码 当然和easyexcel没有关系
        String fileName = URLEncoder.encode("data", "UTF-8").replaceAll("\\+", "%20");
        response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xls");
    }
}

ExcelUtils

package com.dfec.framework.excel.util;

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelReader;
import com.alibaba.excel.read.builder.ExcelReaderBuilder;
import com.alibaba.excel.read.metadata.ReadSheet;
import com.alibaba.excel.util.MapUtils;
import com.alibaba.fastjson.JSON;
import com.dfec.common.exception.ServiceException;
import com.dfec.framework.excel.listener.ExcelListener;
import com.dfec.framework.excel.service.ExcelBaseService;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * @description: Excel 工具类
 * @title: ExcelUtils
 */
public class ExcelUtils {


    /**
     * 将列表以 Excel 响应给前端
     *
     * @param response  响应
     * @param fileName  文件名
     * @param sheetName Excel sheet 名
     * @param head      Excel head 头
     * @param data      数据列表哦
     * @param <T>       泛型，保证 head 和 data 类型的一致性
     * @throws IOException 写入失败的情况
     */
    public static <T> void excelExport(HttpServletResponse response, String fileName, String sheetName,
                                       Class<T> head, List<T> data) throws IOException {
        write(response, fileName);
        // 这里需要设置不关闭流
        EasyExcel.write(response.getOutputStream(), head).autoCloseStream(Boolean.FALSE).sheet(sheetName)
                .doWrite(data);
    }


    /**
     * 根据模板导出
     *
     * @param response     响应
     * @param templatePath 模板名称
     * @param fileName     文件名
     * @param sheetName    Excel sheet 名
     * @param head         Excel head 头
     * @param data         数据列表哦
     * @param <T>          泛型，保证 head 和 data 类型的一致性
     * @throws IOException 写入失败的情况
     */
    public static <T> void excelExport(HttpServletResponse response, String templatePath, String fileName, String sheetName,
                                       Class<T> head, List<T> data) throws IOException {
        write(response, fileName);
        // 这里需要设置不关闭流
        EasyExcel.write(response.getOutputStream(), head).withTemplate(templatePath).autoCloseStream(Boolean.FALSE).sheet(sheetName)
                .doWrite(data);
    }

    /**
     * 根据参数，只导出指定列
     *
     * @param response                响应
     * @param fileName                文件名
     * @param sheetName               Excel sheet 名
     * @param head                    Excel head 头
     * @param data                    数据列表哦
     * @param excludeColumnFiledNames 排除的列
     * @param <T>                     泛型，保证 head 和 data 类型的一致性
     * @throws IOException 写入失败的情况
     */
    public static <T> void excelExport(HttpServletResponse response, String fileName, String sheetName,
                                       Class<T> head, List<T> data, Set<String> excludeColumnFiledNames) throws IOException {
        write(response, fileName);
        // 这里需要设置不关闭流
        EasyExcel.write(response.getOutputStream(), head).autoCloseStream(Boolean.FALSE).excludeColumnFiledNames(excludeColumnFiledNames).sheet(sheetName)
                .doWrite(data);
    }


    private static void write(HttpServletResponse response, String fileName) {
        try {
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
            response.setCharacterEncoding("utf-8");
            // 这里URLEncoder.encode可以防止中文乱码 当然和easyexcel没有关系
            response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");

        } catch (Exception e) {
            // 重置response
            response.reset();
            response.setContentType("application/json");
            response.setCharacterEncoding("utf-8");
            Map<String, String> map = MapUtils.newHashMap();
            map.put("status", "failure");
            map.put("message", "下载文件失败" + e.getMessage());
            try {
                response.getWriter().println(JSON.toJSONString(map));
            } catch (IOException ex) {
                throw new RuntimeException(ex);
            }
        }
    }

    public static <T> List<T> read(MultipartFile file, Class<T> head) throws IOException {
        return EasyExcel.read(file.getInputStream(), head, null)
                // 不要自动关闭，交给 Servlet 自己处理
                .autoCloseStream(false)
                .doReadAllSync();
    }


    /**
     * 读取 Excel(多个 sheet)
     *
     * @param excel    文件
     * @param rowModel 实体类映射
     * @return Excel 数据 list
     */
    public static <T> List<T> readExcelData(MultipartFile excel, Class<T> rowModel, Integer headRowNumber) {
        ExcelListener excelListener = new ExcelListener();
        ExcelReaderBuilder readerBuilder = getReader(excel, excelListener);
        if (readerBuilder == null) {
            return null;
        }
        if (headRowNumber == null) {
            headRowNumber = 1;
        }
        readerBuilder.head(rowModel).headRowNumber(headRowNumber).doReadAll();
        return excelListener.getData();
    }


    /**
     * 读取 Excel(多个 sheet)
     *
     * @param excel    文件
     * @param rowModel 实体类映射
     * @return Excel 数据 list
     */
    public static <T> List<T> excelImport(MultipartFile excel, ExcelBaseService excelBaseService, Class rowModel) {
        ExcelListener excelListener = new ExcelListener(excelBaseService);
        ExcelReaderBuilder readerBuilder = getReader(excel, excelListener);
        if (readerBuilder == null) {
            return null;
        }
        readerBuilder.head(rowModel).doReadAll();
        return excelListener.getData();
    }

    /**
     * 读取某个 sheet 的 Excel
     *
     * @param excel       文件
     * @param rowModel    实体类映射
     * @param sheetNo     sheet 的序号 从1开始
     * @param headLineNum 表头行数，默认为1
     * @return Excel 数据 list
     */
    public static <T> List<T> excelImport(MultipartFile excel, ExcelBaseService excelBaseService, Class rowModel, int sheetNo,
                                          Integer headLineNum) {
        ExcelListener excelListener = new ExcelListener(excelBaseService);
        ExcelReaderBuilder readerBuilder = getReader(excel, excelListener);
        if (readerBuilder == null) {
            return null;
        }
        ExcelReader reader = readerBuilder.headRowNumber(headLineNum).build();
        ReadSheet readSheet = EasyExcel.readSheet(sheetNo).head(rowModel).build();
        reader.read(readSheet);
        return excelListener.getData();
    }

    /**
     * 返回 ExcelReader
     *
     * @param excel         需要解析的 Excel 文件
     * @param excelListener 监听器
     */
    private static ExcelReaderBuilder getReader(MultipartFile excel,
                                                ExcelListener excelListener) {
        String filename = excel.getOriginalFilename();
        if (filename == null || (!filename.toLowerCase().endsWith(".xls") && !filename.toLowerCase().endsWith(".xlsx"))) {
            throw new ServiceException("文件格式错误！");
        }
        InputStream inputStream;
        try {
            inputStream = new BufferedInputStream(excel.getInputStream());
            return EasyExcel.read(inputStream, excelListener);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

}

ExcelListener.java

package com.dfec.framework.excel.listener;

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.alibaba.fastjson.JSON;
import com.dfec.framework.excel.service.ExcelBaseService;
import lombok.extern.slf4j.Slf4j;


import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * @description: Excel导入的监听类
 * @title: ExcelListener
 * @projectName df-platform
 */
@Slf4j
public  class  ExcelListener<T> extends AnalysisEventListener<T> {

    private ExcelBaseService excelBaseService;

    public ExcelListener(){}

    public ExcelListener(ExcelBaseService excelBaseService){
        this.excelBaseService = excelBaseService;
    }

    /**
     * 每隔1000条存储数据库，实际使用中可以3000条，然后清理list ，方便内存回收
     */
    private static final int BATCH_COUNT = 1000;
    List<T> list = new ArrayList<>();

    @Override
    public void invoke(T data, AnalysisContext context) {
        list.add(data);
        log.info("解析到一条数据:{}", JSON.toJSONString(data));

    }

    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {
        log.info("所有数据解析完成！");
    }



    /**
     * 返回list
     */
    public  List<T> getData() {
        return this.list;
    }

}

遇到的问题

1、通过模板导出数据作为导入数据再导入进来，日期格式不正确
解决方法：

package com.dfec.server;

import com.alibaba.excel.converters.Converter;
import com.alibaba.excel.converters.ReadConverterContext;
import com.alibaba.excel.enums.CellDataTypeEnum;
import com.dfec.common.utils.str.StringUtils;

import java.util.Date;

/**
 * DateConverter
 *
 * @className DateConverter
 **/
public class DateConverter implements Converter<Date> {

    @Override
    public Date convertToJavaData(ReadConverterContext<?> context) throws Exception {
        Class<?> aClass = context.getContentProperty().getField().getType();
        CellDataTypeEnum type = context.getReadCellData().getType();
        String stringValue = context.getReadCellData().getStringValue();
        if(aClass.equals(Date.class) && type.equals(CellDataTypeEnum.STRING)  && StringUtils.isBlank(stringValue)){
            return null;
        }
  
        return Converter.super.convertToJavaData(context);
    }
}

实体类上添加

/**
 * 创建时间
 */
@Schema(description = "创建时间")
@ExcelProperty(value = "创建时间",converter = DateConverter.class)
private Date bornDate;

同理，这块

注意这里也是可以用相同的方法去做字典值类型的转换的

2、POI版本
这里切记POI版本和ooxml的版本一堆要保持一致，不然会出现各种问题

3、日期类型 LocalDateTime 转换的问题

package com.dfec.framework.excel.convert;

import com.alibaba.excel.converters.Converter;
import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.GlobalConfiguration;
import com.alibaba.excel.metadata.data.ReadCellData;
import com.alibaba.excel.metadata.data.WriteCellData;
import com.alibaba.excel.metadata.property.ExcelContentProperty;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

/**
 * 解决 EasyExcel 日期类型 LocalDateTime 转换的问题
 */
public class LocalDateTimeConverter implements Converter<LocalDateTime> {

    @Override
    public Class<LocalDateTime> supportJavaTypeKey() {
        return LocalDateTime.class;
    }

    @Override
    public CellDataTypeEnum supportExcelTypeKey() {
        return CellDataTypeEnum.STRING;
    }

    @Override
    public LocalDateTime convertToJavaData(ReadCellData cellData, ExcelContentProperty contentProperty,
                                           GlobalConfiguration globalConfiguration) {
        return LocalDateTime.parse(cellData.getStringValue(), DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
    }

    @Override
    public WriteCellData<String> convertToExcelData(LocalDateTime value, ExcelContentProperty contentProperty,
                                                    GlobalConfiguration globalConfiguration) {
        return new WriteCellData(value.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
    }

}