通过EasyExcel实现导入导出功能（包含偏复杂表头）

EasyExcel是一个基于Java的简单、省内存的读写Excel的开源项目

 首先引入maven

        
            com.alibaba
            easyexcel
            2.1.6
        

一.导出（写）

1.创建导出对象

加@ExcelIgnore 注解后将不作为导出字段  @ExcelProperty("XX")导出的表头

@Data
public class OlderVo {
    @ExcelIgnore
    private String id;

    @ExcelProperty("地区")
    private String area;

    @ExcelProperty("总数")
    private String total;

    private String code;

}

 导出，如果不自定义表头就去掉.head(dead())

    public void exportOlder(HttpServletResponse response) throws IOException {
        List list = XXXXService.exportXXX();
        // 这里注意 有同学反应使用swagger 会导致各种问题，请直接用浏览器或者用postman
        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
        String fileName = URLEncoder.encode("导出", "UTF-8").replaceAll("\\+", "%20");
        response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");
        EasyExcel.write(response.getOutputStream(), OlderVo.class).sheet("模板").head(head()).doWrite(list);
    }



//自定义表头
    private static List> head() {
        List> list = new ArrayList>();
        List head0 = new ArrayList();
        head0.add("地区");
        List head1 = new ArrayList();
        head1.add("总数");
        List head2 = new ArrayList();
        head2.add("60-69周岁");
        head2.add("数量");
        List head3 = new ArrayList();
        head3.add("60-69周岁");
        head3.add("占比");

        list.add(head0);
        list.add(head1);
        list.add(head2);
        list.add(head3);
  
        return list;
    }

 二.读操作(导入获取数据)

1.创建接收的实体

@Data
public class TemplateEntity {

    @ExcelProperty("标号")
    private Integer label;

    @ExcelProperty("字符串")
    private String str;

    @ExcelProperty("数字")
    private Integer num;
}

2.导出接口

    @PostMapping("/getinfo")
    public R importExcel(@RequestPart("file") MultipartFile file) throws IOException {
        R r = templateService.impExcel(file);
        return r;
    }

3.实现类方法

@Service
public class TemplateServiceImpl implements TemplateService {
    @Override
    public R impExcel(MultipartFile file) throws IOException {
        List entities = getTemplateEntities(file);
        System.out.println(entities);
        return R.ok(entities);
    }
    private List getTemplateEntities(MultipartFile file) throws IOException {
        TemplateListener templateListener = new TemplateListener();
        EasyExcel.read(file.getInputStream(),TemplateEntity.class,templateListener).sheet().doRead();
        return templateListener.getDate();
    }
}

4.监听器

public class TemplateListener extends AnalysisEventListener {

    private List list = new ArrayList<>();

    @Override
    public void invoke(TemplateEntity data, AnalysisContext analysisContext) {
        list.add(data);
    }

    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {

    }

    public List getDate(){
        return list;
    }
}

参考：Springboot + Easyexcel读取写入数据，多头行数，多sheet，复杂表头简单实现_鸢尾の的博客-CSDN博客_easyexcel从第三行开始读取