前言：上文讲述如何上传EXCEL文件，从指定行读取数据，且支持行数据与java属性值相互转换，

entity对象定义方式与上文一致

EXCEL上传指定行读取数据_T浩浩的博客-CSDN博客

前提：需要导出的数据

java">List<ProductImportReq> exportList=Lists.newArrayList();

导出方式一：直接通过流返回给前端

java">public void export(HttpServletResponse response) throws IOException {

		List<ProductExportExcelResp> exportList = Lists.newArrayList()；
		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("平台商品主档-"+ LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyyMMdd")), "UTF-8");
//		String fileName = "失败文件-"+LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyyMMdd"));
		response.setHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");
		EasyExcel.write(response.getOutputStream(), ProductExportExcelResp.class)
				.sheet("sheet1")
				// 设置字段宽度为自动调整，不太精确
				.registerWriteHandler(new LongestMatchColumnWidthStyleStrategy())
				.doWrite(exportList);
	}

导出方式二：将List集合转成excel并上传到OSS

excel信息承载类

java">@AllArgsConstructor
@NoArgsConstructor
@Data
public class EasyExcelParams<T> {
	/**
	 * 文件名称
	 */
	private String fileName;
    /**
     * sheet名称
     */
    private String sheetName;

    /**
     * 数据
     */
    private List<T> data;

    /**
     * 数据模型类型
     */
    private Class<T> dataModelClazz;

    /**
     * cell handler
     */
    private List<CellWriteHandler> strategies;

    public EasyExcelParams(String fileName,String sheetName, List<T> data, Class<T> dataModelClazz) {
		this.fileName=fileName;
        this.sheetName = sheetName;
        this.data = data;
        this.dataModelClazz = dataModelClazz;
    }

    public EasyExcelParams(String fileName,String sheetName, List<T> data, Class<T> dataModelClazz, CellWriteHandler... strategies) {
        this(fileName,sheetName, data, dataModelClazz);
        this.strategies = Arrays.asList(strategies);
    }

    public boolean validate() {
     return StringUtils.isNotBlank(sheetName)
                && Objects.nonNull(dataModelClazz)
                && Objects.nonNull(data);
    }

}

流对象处理工具类

java">public class EasyExcelToStreamUtil {
	public static byte[] toInputStream(EasyExcelParams params){
		try {
			return YLZExcelUtils.getExcelBytes(params);
		} catch (ExcelException e) {
			throw new RuntimeException(e);
		}
	}
}

文件上传处理类

java">@RefreshScope
@Component
public class FileUploadUtil<T> {
	@Autowired
	private RemoteFileService remoteFileService;

	@Value(value = "${file.url.prefix}")
	private String prefix;

	public String uploadExcel(String fileName, String sheetName, List<T> data, Class<T> dataModelClazz){
		EasyExcelParams excelParams=new EasyExcelParams(fileName,sheetName,data,dataModelClazz);
		byte[] dateByte = EasyExcelToStreamUtil.toInputStream(excelParams);
		FileUploadDTO fileUploadDTO=new FileUploadDTO();
		fileUploadDTO.setFileName(fileName);
		fileUploadDTO.setData(dateByte);
		R result = remoteFileService.uploadExcel(fileUploadDTO);
		Map<String,String> fileResult= (Map<String, String>) result.getData();
		String fileUrl=null!=fileResult.get("url")? prefix+fileResult.get("url") :"";
		return fileUrl;
	}
}

OSS文件上传实现 上传实现根据项目实际情况选择，实现步骤 1.设置参数 2.将byte[]转成InputStream, 3.上传 保存文件地址

java">@Slf4j
@Service
@AllArgsConstructor
public class SysFileServiceImpl extends ServiceImpl<SysFileMapper, SysFile> implements SysFileService {

//具体上传OSS方式根据项目实际情况选择
private final FileTemplate fileTemplate;

public R uploadExcel(FileUploadDTO fileUploadDTO) {
		Map<String, String> resultMap = new HashMap<>(4);
		resultMap.put("bucketName", properties.getBucketName());
		resultMap.put("fileName", fileUploadDTO.getFileName());
		if(null==fileUploadDTO.getData()){
			return R.ok("");
		}

		try (InputStream inputStream = new ByteArrayInputStream(fileUploadDTO.getData())) {
			fileTemplate.putObject(properties.getBucketName(),                  
fileUploadDTO.getFileName(), inputStream, "vnd.ms-excel");
		}
		catch (Exception e) {
			log.error("上传失败", e);
			return R.failed(e.getLocalizedMessage());
		}
		return R.ok(resultMap);
	}




}