excel的导入与导出---通用版

excel的导入与导出---通用版

web项目关于导入导出的业务场景很常见，最近我就又遇到了这个业务场景。这次将最近半个月做的导入导出总结一下

使用的pom如下,主要还是阿里巴巴的easyexcel依赖。

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>cn.lxiaol</groupId>
    <artifactId>excel_demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>excel_demo</name>
    <description>excel_demo</description>
    <properties>
        <java.version>11</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--easyExcel-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>2.2.6</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.67</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

项目结构如下，一个很简单的小demo

导入

因为我的业务不只是一个模块用到导入，所以定义了一个泛型类。CommonExcelListener具体代码如下

package cn.lxiaol.excel_demo.common.listeners;

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import lombok.extern.slf4j.Slf4j;

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

/**
 * T 是读取到的一行数据转换为的目标类
 * @author lxiaol
 * @date 2021年08月15日 14:14
 */
@Slf4j
public class CommonExcelListener<T> extends AnalysisEventListener<T> {

    /**存放解析到的数据，给了一个初始容量，为了避免list的频繁扩容带来的性能问题*/
    private final List<T> list = new ArrayList<>(1000);

    /**解析每一行都会执行该方法*/
    @Override
    public void invoke(T data, AnalysisContext analysisContext) {
        log.info("解析到一条数据:" + data.toString());
        this.list.add(data);
    }

    /**解析完成*/
    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {
        log.info("解析完成:共解析到{}数据", this.list.size());
    }

    /**解析表头*/
    @Override
    public void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) {
        log.info("解析到一条头数据：{}, currentRowHolder: {}", headMap.toString(), context.readRowHolder().getRowIndex());
        headMap.entrySet().removeIf((h) -> Objects.isNull(h.getValue()) || "".equals(h.getValue()));
        log.info("表头列总数：{},列头为：{}", headMap.size(), headMap.values());
    }

    public List<T> getList() {
        return this.list;
    }

}

假设我这里是用户的账号和手机号的导入，对应的实体类如下：

package cn.lxiaol.excel_demo.dto;

import com.alibaba.excel.annotation.ExcelIgnore;
import com.alibaba.excel.annotation.ExcelProperty;
import lombok.Data;

/**
 * @author lxiaol
 * @date 2021年08月15日 14:16
 */
@Data
public class UserExcelDto {
    @ExcelProperty(value = "用户名", index = 0)
    private String username;

    @ExcelProperty(value = "手机号", index = 1)
    private String phone;

    @ExcelIgnore
    private String password;
}

那么该如何使用呢？下面来简单讲一下，so easy~

首先创建导入所需要的controller

package cn.lxiaol.excel_demo.controller;

import cn.lxiaol.excel_demo.common.listeners.CommonExcelListener;
import cn.lxiaol.excel_demo.dto.UserExcelDto;
import cn.lxiaol.excel_demo.dto.UserExcelParamDto;
import cn.lxiaol.excel_demo.service.ExcelService;
import com.alibaba.excel.EasyExcel;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.List;

/**
 * @author lxiaol
 * @date 2021年08月15日 14:07
 */
@RestController
@RequestMapping("/api/excel")
@Slf4j
public class ExcelController {

    /**导入*/
    @PostMapping(value = "/dataImport", headers = "content-type=multipart/form-data")
    public String dataImport(@RequestParam("file") MultipartFile file) {
        String result = "success";
        try {
            // 实例化对象并传入泛型类型
            CommonExcelListener<UserExcelDto> listener = new CommonExcelListener<>();
            // 调用easyexcel的方法，传入文件流，目标类型，和read监听器,
            // 设置表头所在行，自动去除空字符，设置读取第几个sheet页，并开始读取
            EasyExcel.read(file.getInputStream(), UserExcelDto.class, listener)
                    .headRowNumber(1).autoTrim(true).sheet(0).doRead();
            //读取结束，得到读取到的数据
            List<UserExcelDto> list = listener.getList();
            if (!list.isEmpty()) {
                //.....具体业务逻辑
                System.out.println("读取到数据，进行具体的后续操作");
            } else {
                result = "excel内容不能为空";
            }

        } catch (Exception e) {
            log.error("xxxx导入 报错：", e);
            result = "excel导入报错，请检查数据是否合规";
        }
        return result;
    }

}

简单两行代码，就读取完了excel的内容，相比原生的poi操作简单多了，果然是easyexcel

拿到读取来的数据，就可以做具体的业务了。

导出

好，下面再看一下导出，因为导出也是多个模块都有，所以也写了公用的工具类

package cn.lxiaol.excel_demo.common.utils;

import com.alibaba.excel.annotation.ExcelProperty;
import lombok.Data;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.Field;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.*;
import java.util.stream.Collectors;

/**
 * @author lxiaol
 * @date 2021年08月15日 14:35
 */
@Data
public class ExcelExportUtil {

    //表头
    private String title;
    //各个列的表头
    private String[] heardList;
    //各个列的元素key值
    private String[] heardKey;
    //需要填充的数据信息
    private List<Map> data;
    //字体大小
    private int fontSize = 14;
    //行高
    private int rowHeight = 30;
    //列宽
    private int columWidth = 200;
    //工作表
    private String sheetName = "sheet1";

    /**
     * 开始导出数据信息
     */
    public void exportExport(HttpServletResponse response) throws IOException {
        //创建工作簿
        Workbook wb = new XSSFWorkbook();
        //创建工作表
        Sheet sheet = wb.createSheet(this.sheetName);
        //设置默认行宽
        sheet.setDefaultColumnWidth(20);

        //设置表头样式，表头居中
        CellStyle titleStyle = wb.createCellStyle();
        //设置字体
        Font titleFont = wb.createFont();
        titleFont.setFontHeightInPoints((short) this.fontSize);
        titleStyle.setFont(titleFont);

        //在第1行创建rows
        Row titleRow = sheet.createRow(0);
        //设置列头元素
        Cell cellHead;

        for (int i = 0; i < heardList.length; i++) {
            //背景填充色
            titleStyle.setFillForegroundColor(IndexedColors.GREY_40_PERCENT.index);
            titleStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
            //边框
            titleStyle.setBorderLeft(BorderStyle.THIN);//左边框
            titleStyle.setBorderRight(BorderStyle.THIN);//右边框
            cellHead = titleRow.createCell(i);
            cellHead.setCellValue(heardList[i]);
            cellHead.setCellStyle(titleStyle);
        }

        //开始写入实体数据信息
        //设置数据样式
        CellStyle dataStyle = wb.createCellStyle();
        //设置字体
        Font dataFont = wb.createFont();
//        font.setFontHeightInPoints((short) this.fontSize);
        dataFont.setBold(false);
        dataStyle.setFont(dataFont);
        int count = 1;
        for (Map datum : data) {
            Row row = sheet.createRow(count);
            Cell cell;
            int len = heardKey.length;
            for (int j = 0; j < len; j++) {
                cell = row.createCell(j);
                cell.setCellStyle(dataStyle);
                Object valueObject = datum.get(heardKey[j]);
                String value;
                if (valueObject == null) {
                    valueObject = "";
                }
                if (valueObject instanceof String) {
                    //取出的数据是字符串直接赋值
                    value = (String) datum.get(heardKey[j]);
                } else if (valueObject instanceof Integer) {
                    //取出的数据是Integer
                    value = String.valueOf(((Integer) (valueObject)).floatValue());
                } else if (valueObject instanceof BigDecimal) {
                    //取出的数据是BigDecimal
                    value = String.valueOf(((BigDecimal) (valueObject)).floatValue());
                } else {
                    value = valueObject.toString();
                }
                cell.setCellValue(Objects.isNull(value) ? "" : value);
            }
            count++;
        }
        data.clear();

        //导出数据
        try (OutputStream os = response.getOutputStream()) {
            String fileName = URLEncoder.encode(this.title, StandardCharsets.UTF_8);
            //设置Http响应头告诉浏览器下载这个附件
            response.setHeader("Content-Disposition", "attachment;Filename=" + fileName + ".xlsx");
            wb.write(os);
        } catch (Exception ex) {
            ex.printStackTrace();
            throw new IOException("导出Excel出现严重异常，异常信息：" + ex.getMessage());
        } finally {
            wb.close();
        }
    }

    /**
     * 设置导出excel 的信息
     * 主要用到了反射，获取类中标注的ExcelProperty注解的字段，
     * 然后根据注解的index进行排序
     * @param maps
     * @return
     */
    public static ExcelExportUtil getExcelExportUtil(List<Map> maps, Field[] fields) {
        List<Field> fieldList = Arrays.stream(fields)
                .filter(field -> {
                    ExcelProperty annotation = field.getAnnotation(ExcelProperty.class);
                    if (annotation != null && annotation.index() > -1) {
                        field.setAccessible(true);
                        return true;
                    }
                    return false;
                }).sorted(Comparator.comparing(field -> {
                    int index = -1;
                    ExcelProperty annotation = field.getAnnotation(ExcelProperty.class);
                    if (annotation != null) {
                        index = annotation.index();
                    }
                    return index;
                })).collect(Collectors.toList());

        List<String> title = new ArrayList<>();
        List<String> properties = new ArrayList<>();
        fieldList.forEach(field -> {
            ExcelProperty annotation = field.getAnnotation(ExcelProperty.class);
            if (annotation != null) {
                final String[] value = annotation.value();
                String tit = value[0];
                title.add(tit);
                final String name = field.getName();
                properties.add(name);
            }
        });

        ExcelExportUtil excelExport = new ExcelExportUtil();
        excelExport.setData(maps);
        excelExport.setHeardKey(properties.toArray(new String[0]));
        excelExport.setFontSize(14);
        excelExport.setHeardList(title.toArray(new String[0]));
        return excelExport;
    }
}

再来看一下controller的导出代码

    @Resource
    private ExcelService excelService;

    /**导出*/
    @PostMapping("/dataExport")
    public String dataExport(@RequestBody UserExcelParamDto dto, HttpServletRequest request, HttpServletResponse response) {
        String result = "success";
        try {
            // .....调用具体的业务方法
            excelService.export(dto, request, response);
        } catch (Exception e) {
            e.printStackTrace();
            log.error("安装上线导出 接口报错：", e);
            result = "excel导出报错，请检查数据是否合规";
        }
        return result;
    }

根据前台传过来的筛选条件，调用service层的业务方法

package cn.lxiaol.excel_demo.service;

import cn.lxiaol.excel_demo.common.utils.ExcelExportUtil;
import cn.lxiaol.excel_demo.dto.UserExcelDto;
import cn.lxiaol.excel_demo.dto.UserExcelParamDto;
import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.ss.usermodel.DateUtil;
import org.springframework.stereotype.Service;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * @author lxiaol
 * @date 2021年08月15日 14:31
 */
@Service
@Slf4j
public class ExcelService {

    /**
     * 导出根据筛选条件查询到的数据
     *
     * @param dto      筛选条件
     * @param request
     * @param response
     * @throws IOException
     */
    public void export(UserExcelParamDto dto, HttpServletRequest request,
                       HttpServletResponse response) throws IOException {

        // 模拟从数据库查询到10条数据，真是业务可将这段改为查询数据库获取到list
        List<UserExcelDto> list = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            UserExcelDto userExcelDto = new UserExcelDto();
            userExcelDto.setUsername("用户：" + i);
            userExcelDto.setUsername("手机号：188****8888");
            list.add(userExcelDto);
        }
        // 将 list 数据存放到maps中，主要是为了导出时根据表头填写对应的值
        List<Map> maps = new ArrayList<>();
        list.forEach(po -> maps.add(JSONObject.parseObject(JSONObject.toJSONString(po), Map.class)));

        // 获取到excel导出工具类，并根据传入class设置了表头信息
        ExcelExportUtil excelExportUtil =
                ExcelExportUtil.getExcelExportUtil(maps, UserExcelDto.class.getDeclaredFields());

        excelExportUtil.setTitle("Excel导出_" + DateTimeFormatter.ofPattern("yyyyMMddHHmmss").format(LocalDateTime.now()));
        excelExportUtil.exportExport(response);
    }
}

重点是理解excelExportUtil.exportExport(response)方法。

总的来说 有了easyexcel的加持，excel 的导入到处还是很简单的。

示例代码在码云上，传送门--->ゝ李大龙