Springboot import and export Excel, one-to-many relationship, compound table, merged cell data

foreword

Learning is your own business.

But it's okay to learn from me.

This one-to-many export requirement seems to be quite common indeed: 

The surface refused, and the backhand staged a first-hand practical example.

content:

① Export of one-to-many relational data (merge cells) data

② Import of one-to-many relational data (merge cells) data

Import and export a piece to the whole, directly kill the game.

(Watchers, keep it for later use. Give me a like.)

I wrote an extremely simple excel import and export before, which is a single file:

Springboot is the easiest to combine MYSQL data to realize EXCEL table export and data import - Programmer Sought

I also wrote a single, multiple excel file export, converted into a ZIP package:

SpringBoot exports multiple Excel files and compresses them into .zip format for download - Programmer Sought
 

There is also a specified template exported:
Springboot specifies a custom template to export an Excel file - Programmer Sought

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Simulate a business scenario with this kind of data:

Effect, data export:
 

Actual combat:
 

First look at the project directory structure:

pom.xml introduces core dependencies:
 

    <dependencies>
        <dependency>
            <groupId>cn.afterturn</groupId>
            <artifactId>easypoi-spring-boot-starter</artifactId>
            <version>4.1.3</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.10</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

The core of this article is to use easypoi's annotations

@Excel()

Key Notes for Merged Cells and Compound Tables 

@ExcelCollection()

Project team class

ProjectGroupExcelVO.java

import cn.afterturn.easypoi.excel.annotation.Excel;
import cn.afterturn.easypoi.excel.annotation.ExcelCollection;
import lombok.Data;
import java.util.List;

/**
 * @Author: JCccc
 * @Description:
 * @Date: 1/1/1 1:11
 */
@Data
public class ProjectGroupExcelVO {

    @Excel(name = "小组名称", needMerge = true, width = 20,height = 8)
    private String groupName;

    @Excel(name = "小组口号", needMerge = true, width = 20,height = 8)
    private String groupSlogan;

    @Excel(name = "小组类型", needMerge = true, width = 20,height = 8)
    private String groupType;

    @ExcelCollection(name = "组员信息")
    private List<GroupUserExcelVO> groupUsers;
    
}

Brief analysis:

class of members

GroupUserExcelVO.java

import cn.afterturn.easypoi.excel.annotation.Excel;
import lombok.Data;

/**
 * @Author: JCccc
 * @Description:
 * @Date: 1/1/1 1:11
 */
@Data
public class GroupUserExcelVO {

    @Excel(name = "组员名字", width = 20,height = 8)
    private String name;

    @Excel(name = "组员电话", width = 20,height = 8)
    private String phone;

    @Excel(name = "年龄",  width = 20,height = 8)
    private Integer age;

}

Import and export tool class one

MyExcelUtils.java

import cn.afterturn.easypoi.excel.ExcelExportUtil;
import cn.afterturn.easypoi.excel.ExcelImportUtil;
import cn.afterturn.easypoi.excel.entity.ExportParams;
import cn.afterturn.easypoi.excel.entity.ImportParams;
import org.apache.poi.ss.usermodel.Workbook;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.net.URLEncoder;
import java.util.List;
import java.util.NoSuchElementException;

/**
 * @Author: JCccc
 * @Description:
 * @Date: 1/1/1 1:11
 */
public class MyExcelUtils {


    /**
     * 功能描述：复杂导出Excel，包括文件名以及表名,不创建表头
     *
     * @param list 导出的实体类
     * @param title 表头名称
     * @param sheetName sheet表名
     * @param pojoClass 映射的实体类
     * @param fileName
     * @param response
     * @return
     */
    public static void exportExcel(	List<?> list, String title, String sheetName, Class<?> pojoClass,
                                       String fileName, HttpServletResponse response) {
        defaultExport(list, pojoClass, fileName, response, new ExportParams(title, sheetName));
    }

    /**
     * 功能描述：默认导出方法
     *
     * @param list 导出的实体集合
     * @param fileName 导出的文件名
     * @param pojoClass pojo实体
     * @param exportParams ExportParams封装实体
     * @param response
     * @return
     */
    private static void defaultExport(	List<?> list, Class<?> pojoClass, String fileName,
                                          HttpServletResponse response, ExportParams exportParams) {
        Workbook workbook = ExcelExportUtil.exportExcel(exportParams, pojoClass, list);
        if (workbook != null) {
            downLoadExcel(fileName, response, workbook);
        }
    }

    /**
     * 功能描述：Excel导出
     *
     * @param fileName 文件名称
     * @param response
     * @param workbook Excel对象
     * @return
     */
    private static void downLoadExcel(	String fileName, HttpServletResponse response,
                                          Workbook workbook) {
        try {
            response.setCharacterEncoding("UTF-8");
            response.setHeader("content-Type", "multipart/form-data");
            response.setHeader("Content-Disposition",
                    "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
            workbook.write(response.getOutputStream());

        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }


    /**
     * 功能描述：根据接收的Excel文件来导入Excel,并封装成实体类
     *
     * @param file 上传的文件
     * @param titleRows 表标题的行数
     * @param headerRows 表头行数
     * @param pojoClass Excel实体类
     * @return
     */
    public static <T> List<T> importExcel(	MultipartFile file, Integer titleRows, Integer headerRows,
                                              Class<T> pojoClass) {
        if (file == null) {
            return null;
        }
        ImportParams params = new ImportParams();
        params.setTitleRows(titleRows);
        params.setHeadRows(headerRows);
        List<T> list = null;
        try {
            list = ExcelImportUtil.importExcel(file.getInputStream(), pojoClass, params);
        } catch (NoSuchElementException e) {
            throw new RuntimeException("excel文件不能为空");
        } catch (Exception e) {
            throw new RuntimeException(e.getMessage());

        }
        return list;
    }
}

Export interface:

TestController.java

import com.jc.excel.excelVO.GroupUserExcelVO;
import com.jc.excel.excelVO.ProjectGroupExcelVO;
import com.jc.excel.util.MyExcelUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletResponse;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;

/**
 * @Author: JCccc
 * @Description:
 * @Date: 1/1/1 1:11
 */
@RestController
public class TestController {


    /**
     * excel导出 
     *
     * @return
     */
    @GetMapping(value = "/exportTest")
    public void export(HttpServletResponse response) {


        List<ProjectGroupExcelVO> projectGroupList=new ArrayList<>();

        //小组A数据模拟
        ProjectGroupExcelVO groupA=new ProjectGroupExcelVO();
        groupA.setGroupName("小组A");
        groupA.setGroupSlogan("天天向上,爱学习！");
        groupA.setGroupType("奋斗类型");
        List<GroupUserExcelVO> groupUserAList=new ArrayList<>();
        GroupUserExcelVO groupUser1=new GroupUserExcelVO();
        groupUser1.setName("小收");
        groupUser1.setPhone("123456");
        groupUser1.setAge(18);

        GroupUserExcelVO groupUser2=new GroupUserExcelVO();
        groupUser2.setName("小藏");
        groupUser2.setPhone("654321");
        groupUser2.setAge(20);
        groupUserAList.add(groupUser1);
        groupUserAList.add(groupUser2);
        groupA.setGroupUsers(groupUserAList);


        //小组B数据模拟
        ProjectGroupExcelVO groupB=new ProjectGroupExcelVO();
        groupB.setGroupName("小组B");
        groupB.setGroupSlogan("跟着JC学java，稳！");
        groupB.setGroupType("努力类型");
        List<GroupUserExcelVO> groupBUserBList=new ArrayList<>();
        GroupUserExcelVO groupUserB1=new GroupUserExcelVO();
        groupUserB1.setName("小点");
        groupUserB1.setPhone("123456");
        groupUserB1.setAge(12);

        GroupUserExcelVO groupUserB2=new GroupUserExcelVO();
        groupUserB2.setName("小赞");
        groupUserB2.setPhone("654321");
        groupUserB2.setAge(15);

        GroupUserExcelVO groupUserB3=new GroupUserExcelVO();
        groupUserB3.setName("JCccc");
        groupUserB3.setPhone("136919xxxxx");
        groupUserB3.setAge(10000);

        groupBUserBList.add(groupUserB1);
        groupBUserBList.add(groupUserB2);
        groupBUserBList.add(groupUserB3);
        groupB.setGroupUsers(groupBUserBList);
        
        projectGroupList.add(groupA);
        projectGroupList.add(groupB);
        
        
        String time = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy_MM_dd_HH_mm_ss"));
       
        MyExcelUtils.exportExcel(projectGroupList,
                "小组信息",
                "小组信息",
                ProjectGroupExcelVO.class,
                "小组信息文件"+time+".xls",response);



    }

}

Call it to see the effect of the export:
 

 Very OK:

Next is import, write a simple interface to play:

data:

Import interface code:
 

    /**
     * excel导入
     *
     * @return
     */
    @PostMapping(value = "/importTest")
    public void importTest( @RequestParam("file") MultipartFile file) {
        List<ProjectGroupExcelVO> projectGroupExcelVOList = MyExcelUtils.importExcel(file, 1, 2, ProjectGroupExcelVO.class);

        System.out.println(projectGroupExcelVOList.toString());

        System.out.println("-----------------------------------");

        System.out.println("写入数据库");
    }

Call to see the effect:

 The import is successful, it's that simple.