Java使用easyexcel实现导入导出功能

Easyexcel是阿里开源的, 简单, 可快速集成的excel文件导入导出工具, 能够有效的节省内存, 避免出现OOM问题. 原理: 不是一次性将内容全部读取, 而是一行行读取, 从而降低内存的使用.

pom.xml

<dependency>
  <groupId>com.alibaba</groupId>
  <artifactId>easyexcel</artifactId>
  <version>2.1.7</version>
</dependency>

导入

创建bean, 对应excel的表头名称及位置

@Data
@NoArgsConstructor
@AllArgsConstructor
public class WhitelistFileUploadRequest {

    @ExcelProperty(value = "Phone", index = 0)
    private String mobile;

    @ExcelProperty(value = "Sourcecode", index = 1)
    private String sourceCode;

}

创建Listener

@Component
public class WhitelistFileReadListener implements ReadListener<WhitelistFileUploadRequest>, ApplicationContextAware {

    private static CardWhitelistFileService whitelistFileService;

    private List<WhitelistFileUploadRequest> list = new ArrayList<>();

	// 自定义属性
    private String operatorId;
    private String fileName;

    public WhitelistFileReadListener() {
    }

    public WhitelistFileReadListener(String operatorId, String fileName) {
        this.operatorId = operatorId;
        this.fileName = fileName;
    }

    @Override
    public void onException(Exception e, AnalysisContext analysisContext) throws Exception {
        if (e instanceof ExcelDataConvertException) {
            ExcelDataConvertException ce = (ExcelDataConvertException) e;
            log.error("白名单上传解析异常: {} {}", ce.getRowIndex(), ce.getColumnIndex());
        } else {
            log.error("白名单上传解析异常: ", e);
        }
    }

    @Override
    public void invokeHead(Map<Integer, CellData> map, AnalysisContext analysisContext) {
        log.info("白名单上传 头部: {}", JSON.toJSONString(map));
    }

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

    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {
        log.info("白名单上传解析完成: {} {}", fileName, list.size());
        // TODO 对list进行操作入库
    }

    @Override
    public boolean hasNext(AnalysisContext analysisContext) {
        return true;
    }


    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        whitelistFileService = applicationContext.getBean(CardWhitelistFileService.class);
    }

}

文件上传及导入 入口

 @PostMapping("/upload")
public Result upload(@RequestParam("file") MultipartFile file, @RequestAttribute(LoginConstant.TOKEN_UID) String operatorId) {
    if (StringUtils.isEmpty(file.getOriginalFilename())) {
        return new Result().failed("File is null");
    }
   try {
        EasyExcel.read(
                file.getInputStream(),
                WhitelistFileUploadRequest.class,
                new WhitelistFileReadListener(operatorId, file.getOriginalFilename())).sheet().doRead();
    } catch (IOException | FailureException e) {
        log.error("文件上传解析失败: ", e);
        return new Result().failed("Save file failed");
    }
    return new Result<>().success(null);
}

导出

创建bean, 定义表头名称及位置

@Data
@ApiModel("信息返回")
@JsonInclude(JsonInclude.Include.NON_NULL)
public class TestExportResponse implements Serializable {

    @ApiModelProperty("sn")
    @ExcelProperty(value = "SN", index = 0)
    private String sn;

    @ApiModelProperty("Name")
    @ExcelProperty(value = "Name", index = 1)
    private String name;

    @ApiModelProperty("Phone")
    @ExcelProperty(value = "Phone", index = 2)
    private String Phone;
    
}

导出 入口

@PostMapping("/listExport")
@ApiOperation("列表导出")
public ResultVo listExport(HttpServletResponse response) {
    try {
    	List<TestExportResponse> exportList = new ArrayList<>();
    	// TODO 添加数据
        response.setContentType("application/vnd.ms-excel");
        response.setCharacterEncoding("utf-8");
        String fileName = URLEncoder.encode("excel_list", "UTF-8");
        response.setHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");
        EasyExcel.write(response.getOutputStream(), TestExportResponse.class).sheet("excel_list").doWrite(exportList);
    } catch (Exception e) {
        throw CrmExceptionEnum.FAIL.throwCrmException();
    }
    return ResultVo.success();
}