excel文件数据下载，超实用

第一步，首先添加依赖

<dependency>
    <groupId>cn.afterturn</groupId>
    <artifactId>easypoi-base</artifactId>
    <version>3.0.3</version>
</dependency>
<dependency>
    <groupId>cn.afterturn</groupId>
    <artifactId>easypoi-web</artifactId>
    <version>3.0.3</version>
</dependency>
<dependency>
    <groupId>cn.afterturn</groupId>
    <artifactId>easypoi-annotation</artifactId>
    <version>3.0.3</version>
</dependency>

第二步，在公共类里面写一个beanUtil类

package com.ruoyi.system.order;


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 cn.afterturn.easypoi.excel.entity.enmus.ExcelType;
import org.apache.commons.lang3.StringUtils;
import org.apache.poi.ss.usermodel.Workbook;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.File;

import java.io.IOException;
import java.net.URLEncoder;
import java.util.List;

import java.util.Map;
import java.util.NoSuchElementException;

public class ExcelUtil {

    public static void exportExcel(List<?> list, String title, String sheetName, Class<?> pojoClass,String fileName,boolean isCreateHeader, HttpServletResponse response){
        ExportParams exportParams = new ExportParams(title, sheetName);
        exportParams.setCreateHeadRows(isCreateHeader);
        defaultExport(list, pojoClass, fileName, response, exportParams);

    }
    //导出
    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));
    }
    public static void exportExcel(List<Map<String, Object>> list, String fileName, HttpServletResponse response){
        defaultExport(list, fileName, response);
    }

    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);
        }

    }

    private static void downLoadExcel(String fileName, HttpServletResponse response, Workbook workbook) {
        try {
            response.setCharacterEncoding("UTF-8");
            response.setHeader("content-Type", "application/vnd.ms-excel");
            response.setHeader("Content-Disposition",
                    "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
            workbook.write(response.getOutputStream());
        } catch (IOException e) {
            throw new RuntimeException(e.getMessage());
        }
    }
    private static void defaultExport(List<Map<String, Object>> list, String fileName, HttpServletResponse response) {
        Workbook workbook = ExcelExportUtil.exportExcel(list, ExcelType.HSSF);
        if (workbook != null) {
            downLoadExcel(fileName, response, workbook);
        }

    }

    //导入
    public static <T> List<T> importExcel(String filePath,Integer titleRows,Integer headerRows, Class<T> pojoClass){
        if (StringUtils.isBlank(filePath)){
            return null;
        }
        ImportParams params = new ImportParams();
        params.setTitleRows(titleRows);
        params.setHeadRows(headerRows);
        List<T> list = null;
        try {
            list = ExcelImportUtil.importExcel(new File(filePath), pojoClass, params);
        }catch (NoSuchElementException e){
            throw new RuntimeException("模板不能为空");
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e.getMessage());
        }
        return list;
    }
    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;
    }



}

第三步，实体类。orderNum指定excel的列。name为excel表头。

public class UserTest implements Serializable {
    /** 用户id */
    private String userId;

    /** 用户昵称 */
    @Excel(name = "用户昵称",orderNum = "0")
    private String userNickname;

    //    @ApiModelProperty(value = "联系方式")
    @Excel(name = "联系方式",orderNum = "1")
    @JsonProperty("bindPhone")
    private String bindPhone;

    /** 用户头像链接 */
    @Excel(name = "用户头像链接",orderNum = "2")
    private String avatar;}

第四步，就是controller->service->mapper>xml

@RestController
@CrossOrigin
@RequestMapping(value = "/foreign")
public class ExcelTest {
    @Autowired
   private IJJmopUserMapper ijJmopUserMapper;
    @RequestMapping(value = "/find/excelTest",method = RequestMethod.GET)
    public void findUserTest(HttpServletResponse response){
        Map map1 = new HashMap();
        List <UserTest>list = new ArrayList();
        List<JJmopUser>jJmopUserList =ijJmopUserMapper.selectJJmopUserList(map1);
//我这里因为测试实体类有区别，所以做了一个转换，正常可以直接jJmopUserList 替代list
        for (JJmopUser jJmopUser:jJmopUserList){
            UserTest userTest = new UserTest();
            BeanUtils.copyProperties(jJmopUser,userTest);
            list.add(userTest);
        }

        ExcelUtil.exportExcel(list,"用户信息","sheet1",UserTest.class,"testDATA.xls", (HttpServletResponse) response);

    }
}

本博客也是借鉴其他大佬的，原文链接：Springboot 最简单的结合MYSQL数据实现EXCEL表格导出及数据导入_小目标青年的博客-优快云博客_springboot导入excel数据