springboot easyexcel导出百万数据优化

àì夳堔傛蜴生んèń 2022-12-11 05:28 467阅读 0赞

## 说明 ##

> 由于某些原因系统jvm内存最大只能给到512，但是要导出百万数据该如何实现呢？传统的一次性导出肯定是不行的

## 优化 ##

Excel导出基于 springboot , easyexcel  
依赖：

<dependency>
    			<groupId>com.alibaba</groupId>
    			<artifactId>easyexcel</artifactId>
    			<version>2.2.6</version>
    		</dependency>

### 导出优化 ###

基于自增id滚动式查询写入

@GetMapping("/standard-product-ext/export")
        public void productExtExport(HttpServletResponse response, StandardProductExtQuery query) throws Exception{ 
    
            String today = DateUtil.today();
            String fileName = "标准商品标签导入模板" + today;
            String fileNameCode = URLEncoder.encode(fileName, "UTF-8");
    
            response.setContentType("application/force-download");
            response.setHeader("Content-Disposition", "attachment;filename=" + fileNameCode + ".xlsx");
            ExcelWriter writer = new ExcelWriterBuilder()
                    .autoCloseStream(true)
                    .file(response.getOutputStream())
                    .head(DscStandardProductExtVO.class)
                    .build();
            Integer lastBatchMaxId = 0;
            query.setLastBatchMaxId(lastBatchMaxId);
            WriteSheet writeSheet = new WriteSheet();
            writeSheet.setSheetName("标准商品标签导入模板" + today);
            List<DscStandardProductExtVO> productExt
            for (; ; ) { 
                productExt = dictionaryService.getProductExt(query);
                if (productExt.isEmpty()) { 
                    writer.write(productExt, writeSheet);
                    writer.finish();
                    break;
                } else { 
                    lastBatchMaxId = productExt.stream().map(DscStandardProductExtVO::getId).max(Integer::compareTo).orElse(Integer.MAX_VALUE);
                    query.setLastBatchMaxId(lastBatchMaxId);
                    writer.write(productExt, writeSheet);
                }
    
    
            }
        }

*  dictionaryService.getProductExt(query) 的xml

SELECT
           *
            FROM
            base_drug
            where
            id > #{ lastBatchMaxId}

## 导入优化 ##

*  使用 easyexcel 监听器导出

@PostMapping("/standard-product-ext/import")
        public ResponseResult productExtImport(MultipartFile file) throws IOException { 
    
            File localFile = new File(appSettings.getTempdir() + RandomStringUtils.randomAlphanumeric(12) + file.getOriginalFilename());
            // 将上传文件 写入到 localFile 本地文件，后续对 localFile 操作读取
            FileUtils.multipartFileToFile(file, localFile);
            try { 
                ExcelUploadResult excelUploadResult = dictionaryService.updateBatchProductExtByFile(localFile);
                return ResponseUtils.success(excelUploadResult);
            } catch (DaoException e) { 
                ResponseUtils.fail(ErrorCodeConstants.FAIL, "导入标准商品标签失败");
            }
            return null;
    
        }

> dictionaryService.updateBatchProductExtByFile(localFile) 方法

public ExcelUploadResult updateBatchProductExtByFile(File excelFile) throws DaoException{ 
            StandardProductExtListener listener = new StandardProductExtListener(clearSearchDao,
                    dscStandardProductExtDao, cosUtils, appSettings);
            try { 
                EasyExcel.read(excelFile, DscStandardProductExtVO.class, listener).sheet().doRead();
            } catch (Exception e) { 
                log.error("[标签导入]读取excel出错", e);
                throw new ServiceException("excel导入失败");
            } finally { 
                if (excelFile.exists()) { 
                    excelFile.delete();
                }
            }
            int successTotal = listener.getSuccessTotal();
            int total = listener.getTotal();
            int error = listener.getError();
            ExcelUploadResult result =  error > 0 ? new ExcelUploadResult(total, successTotal,error, listener.getErrorFileUrl())
            : new ExcelUploadResult(successTotal, total, 0, null);
            return result;
        }

*  StandardProductExtListener

> 需要注意的是 StandardProductExtListener 不能被spirng管理，需要手动new，依赖spring的类通过构造方法注入，这里是官方说明的，如果给spirng管理会有什么问题暂时没有尝试

public class StandardProductExtListener extends AnalysisEventListener<DscStandardProductExtVO> { 
    
    
        int successTotal = 0;
        int total = 0;
        int error = 0;
        String errorFileUrl;
    
        List<DscStandardProductExtVO> list = new ArrayList<>();
    
        ClearSearchDao clearSearchDao;
    
        DscStandardProductExtDao dscStandardProductExtDao;
    
        CosUtils cosUtils;
    
        AppSettings appSettings;
    
        List<DscStandardProductExtVO> errorList = Lists.newArrayList();
    
        public StandardProductExtListener(ClearSearchDao clearSearchDao, DscStandardProductExtDao dscStandardProductExtDao,
                                          CosUtils cosUtils, AppSettings appSettings) { 
            this.clearSearchDao = clearSearchDao;
            this.dscStandardProductExtDao = dscStandardProductExtDao;
            this.cosUtils = cosUtils;
            this.appSettings = appSettings;
        }
    
    
    
    
        /** * 每条数据的解析 * @param vo * @param analysisContext */
        @Override
        public void invoke(DscStandardProductExtVO vo, AnalysisContext analysisContext) { 
            list.add(vo);
            if (list.size() > 3000) { 
                try { 
                    doFile(list);
                    total += list.size();
                    list.clear();
                } catch (DaoException e) { 
                    e.printStackTrace();
                }
            }
    
        }
    
        @Override
        public void doAfterAllAnalysed(AnalysisContext analysisContext) { 
            try { 
                total += list.size();
                doFile(list);
                log.info("处理最后数据{}", total);
                errorFileUrl = updateErrorFile();
            } catch (DaoException e) { 
                e.printStackTrace();
            }
        }
    
        public void doFile(List<DscStandardProductExtVO> readExcels) throws DaoException{ 
           // 业务逻辑处理
           }
    
    
    }

## 总结 ##

经过测试 导出百万数据 使用这两种优化没什么问题，只是导入速度可能有点慢，但是不会OOM，其次可能系统full gc会相对严重。