架构（十二）动态Excel-编程知识

一、引言

作者最近的平台项目需要生成excel，excel的导入导出是常用的功能，但是作者想做成动态的，不要固定模板，那就看看怎么实现。

二、后端

先捋一下原理，前后端的交互看起来是制定好的接口，其实根本上是数据键值对的映射，后端可以直接用Map进行接收，只不过接收回来的数据如果是对象嵌套对象或者集合嵌套，那么就要用object接收之后再解析。

而对于excel的导入导出来说，基本上都是转字符串再去填入文件，也不会有什么嵌套，所以可以直接用Map接收。

1、pom

先引入工具包

<dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml</artifactId><version>3.17</version><exclusions><exclusion><groupId>org.apache.xmlbeans</groupId><artifactId>xmlbeans</artifactId></exclusion></exclusions></dependency>

2、导入

导入按功能不同，步骤也不一样，如果是为了业务处理，那就是把excel数据解析之后处理完，前端再去查

作者这边是解析完excel之后把数据直接给前端，一个意思，主要是解析excel

首先要把excel给下载下来

@Service
public class ExcelWDownloadUtil {private static final LoggerService LOG = LoggerServiceFactory.getLoggerService(FileWsHelper.class);private static final String TITLE = "ExcelWDownloadUtil";/*** Function - 下载文件** @param fileUrl 文件路径* @return 文件内容*/public byte[] downloadBytes(String fileUrl) {HttpGet httpGet = new HttpGet(fileUrl);return HttpClientHelper.getInstance().getBytes(httpGet);}/*** excel文件后缀*/private static final String EXCEL_FIX = "xlsx";private static final String EXCEL_FIX_OLD = "xls";/*** 文件后缀分隔符*/private final static String FILE_SPLIT = ".";public List<List<String>> downloadExcel(String excelDownloadUrl) {// 1. 通过http下载文件，并转为bytesbyte[] fileBytes = downloadBytes(excelDownloadUrl);// 2. 将byte数组转为流ByteArrayInputStream byteInputStream = new ByteArrayInputStream(fileBytes);// 3. 将流转为excel工作薄String fileType = getFileType(excelDownloadUrl);if (StringUtilsExt.equals(fileType, EXCEL_FIX)) {return convertXlsxExcel(byteInputStream);} else if (StringUtilsExt.equals(fileType, EXCEL_FIX_OLD)) {return convertXlsExcel(byteInputStream);}LOG.error(TITLE, "file is not excel");return null;}public List<List<String>> convertXlsxExcel(ByteArrayInputStream byteInputStream) {List<List<String>> res = new ArrayList<>();XSSFWorkbook sheets = null;try {// 1. 转为工作薄sheets = new XSSFWorkbook(byteInputStream);// 2. 取第一个SheetXSSFSheet sheet = sheets.getSheetAt(0);// 3. 循环行列，转为String返回DataFormatter formatter = new DataFormatter();for (int i = 0; i <= sheet.getLastRowNum(); i++) {List<String> rowString = getStringFormRow(sheet.getRow(i), formatter);if (CollectionUtilsExt.isNotBlank(rowString)) {res.add(rowString);}}} catch (IOException e) {LOG.error(TITLE, e);throw new FileExecuteException("excel file io exception");} finally {// 关闭文件流if (sheets != null) {try {sheets.close();} catch (IOException e) {LOG.error(TITLE, e);}}}return res;}public List<List<String>> convertXlsExcel(ByteArrayInputStream byteInputStream) {List<List<String>> res = new ArrayList<>();HSSFWorkbook sheets = null;try {// 1. 转为工作薄sheets = new HSSFWorkbook(byteInputStream);// 2. 取第一个SheetHSSFSheet sheet = sheets.getSheetAt(0);// 3. 循环行列，转为String返回DataFormatter formatter = new DataFormatter();for (int i = 0; i < sheet.getLastRowNum(); i++) {List<String> rowString = getStringFormRow(sheet.getRow(i), formatter);if (CollectionUtilsExt.isNotBlank(rowString)) {res.add(rowString);}}} catch (IOException e) {LOG.error(TITLE, e);throw new FileExecuteException("excel file io exception");} finally {// 关闭文件流if (sheets != null) {try {sheets.close();} catch (IOException e) {LOG.error(TITLE, e);}}}return res;}private List<String> getStringFormRow(Row row, DataFormatter formatter) {if (Objects.isNull(row)) {return null;}List<String> rowString = new ArrayList<>();for (int j = 0; j < row.getLastCellNum(); j++) {rowString.add(getStringFromCell(row.getCell(j), formatter));}return rowString;}private String getStringFromCell(Cell cell, DataFormatter formatter) {if (Objects.isNull(cell)) {return null;}if (CellType.NUMERIC == cell.getCellTypeEnum()) {BigDecimal num = BigDecimal.valueOf(cell.getNumericCellValue());// 判断是否有小数，防止1变成了1.0，下游会报错if (new BigDecimal(num.intValue()).compareTo(num) == 0) {return String.valueOf(num.intValue());}// 这里是防止出现科学计数法return NumberToTextConverter.toText(cell.getNumericCellValue());} else {return formatter.formatCellValue(cell);}}public static String getFileType(String fileName) {if (StringUtilsExt.isBlank(fileName) || !fileName.contains(FILE_SPLIT)) {return null;}return fileName.substring(fileName.lastIndexOf(FILE_SPLIT) + 1);}}

解析成键值对，说白了解析excel得到的List<List<String>>，第一行是列名作为键，下面行数据都作为值

if (CollectionUtilsExt.isBlank(fileList) || fileList.size() <= 1) {throw new OrderException("EXCEL_NO_DATA");}List<Map<String, String>> res = new ArrayList<>();List<String> cellName = fileList.get(0);for (int i = 1; i < fileList.size(); i++) {List<String> row = fileList.get(i);Map<String, String> rowMap = new HashMap<>();for (int j = 0; j < row.size(); j++) {rowMap.put(cellName.get(j), row.get(j));}res.add(rowMap);}return res;

3、导出

导出的话就是把数据生成excel，第一把前端传的数据或者数据库查出来的数据生成excel，第二步把excel上传内部服务器，第三步把生成文件的地址给前端打开

生成excel

@Service
public class GenerateExcelUtil {private static final int SHEET_ROW = 1000;private static final short FONT_SIZE = 11;private int getCellWidth(String cellName) {// 根据列名获取配置的列宽度，不配置也行，默认宽度Map<String, String> cellWidthMap = Config.getMap(CELL_WIDTH_MAP);if (cellWidthMap == null || !cellWidthMap.containsKey(cellName)) {return 4000;}return Integer.parseInt(cellWidthMap.get(cellName));}private short getCellColor(String cellName) {// 根据列名获取配置的列颜色，不配置也行，默认颜色Map<String, String> cellColorMap = Config.getMap(CELL_COLOR_MAP);if (cellColorMap == null || !cellColorMap.containsKey(cellName)) {return 0;}return Short.parseShort(cellColorMap.get(cellName));}public SXSSFWorkbook generateExcel(String sheetName, List<Map<String, String>> excelBoList,List<String> cellNameList) {// 生成excel文件SXSSFWorkbook workbook = new SXSSFWorkbook(SHEET_ROW);// 建表SXSSFSheet sheet = workbook.createSheet(sheetName);// 设置每列宽度for (int i = 0; i < cellNameList.size(); i++) {sheet.setColumnWidth(i, getCellWidth(cellNameList.get(i)));}// 构建表头SXSSFRow rowHead = sheet.createRow(0);for (int i = 0; i < cellNameList.size(); i++) {createCell(rowHead, i, cellNameList.get(i), createTitleStyle(workbook, getCellColor(cellNameList.get(i))));}// 构建内容CellStyle contentStyle = createContentStyle(workbook);for (int i = 0; i < excelBoList.size(); i++) {Map<String, String> excelBo = excelBoList.get(i);createRow(sheet, i + 1, excelBo, contentStyle, cellNameList);}return workbook;}private CellStyle createTitleStyle(SXSSFWorkbook workbook, short color) {Font boldFont = workbook.createFont();boldFont.setFontHeightInPoints(FONT_SIZE);boldFont.setBold(true);boldFont.setColor(color);CellStyle style = workbook.createCellStyle();style.setFont(boldFont);style.setWrapText(true);style.setAlignment(HorizontalAlignment.CENTER);style.setVerticalAlignment(VerticalAlignment.CENTER);style.setBorderBottom(BorderStyle.THIN);style.setBorderLeft(BorderStyle.THIN);style.setBorderRight(BorderStyle.THIN);style.setBorderTop(BorderStyle.THIN);return style;}private CellStyle createContentStyle(SXSSFWorkbook workbook) {Font boldFont = workbook.createFont();boldFont.setFontHeightInPoints(FONT_SIZE);CellStyle style = workbook.createCellStyle();style.setFont(boldFont);style.setWrapText(true);style.setAlignment(HorizontalAlignment.CENTER);style.setVerticalAlignment(VerticalAlignment.CENTER);return style;}private void createCell(SXSSFRow row, int column, Object value, CellStyle style) {SXSSFCell cell = row.createCell(column);cell.setCellType(CellType.STRING);cell.setCellValue(Null.or(value, Object::toString, null));cell.setCellStyle(style);}private void createRow(SXSSFSheet sheet, int rowIndex, Map<String, String> map, CellStyle style,List<String> cellName) {SXSSFRow row = sheet.createRow(rowIndex);for (int i = 0; i < cellName.size(); i++) {createCell(row, i, map.get(cellName.get(i)), style);}}}

上传服务器

@Service
public class ExcelUploadUtil {private static final LoggerService LOG = LoggerServiceFactory.getLoggerService(ExcelUploadUtil.class);private static final String TITLE = "ExcelUploadUtil";/*** 上传文件的地址*/private static final String UPLOAD_URL = "fileUploadUrl";/*** 上传文件的contentType*/private static final String EXCEL_CONTENT_TYPE ="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";/*** 创建文件的后缀*/public static final String FILE_SUFFIX = ".xlsx";/*** 请求头*/private static final String CONTENT_TYPE = "Content-Type";public FileResponseBo uploadExcel(SXSSFWorkbook workbook, String filePrefix) {File file = convertFile(workbook, filePrefix);LOG.info(TITLE, "convertFile");if (file == null) {return null;}return uploadFile(file, EXCEL_CONTENT_TYPE);}private File convertFile(SXSSFWorkbook workbook, String filePrefix) {File file = null;FileOutputStream fos = null;try {file = File.createTempFile(filePrefix, FILE_SUFFIX);fos = new FileOutputStream(file);workbook.write(fos);} catch (IOException e) {// 这里上传文件有io异常无需处理，后续返回空，会对空处理LOG.error(TITLE, e);} finally {// 关闭文件流if (fos != null) {try {fos.close();} catch (IOException e) {LOG.error(TITLE, e);}}// 删除临时xml文件workbook.dispose();}return file;}/*** 上传文件* * @param file* @param contentType* @return*/private FileResponseBo uploadFile(File file, String contentType) {String uploadUrl = Config.get(UPLOAD_URL);LOG.info(TITLE, "uploadUrl:{}", uploadUrl);HttpPost httpPost = new HttpPost(uploadUrl);httpPost.setHeader(CONTENT_TYPE, contentType);FileEntity fileEntity = new FileEntity(file);httpPost.setEntity(fileEntity);String res = HttpClientHelper.getInstance().doPost(httpPost);LOG.info(TITLE, "res:{}", res);return JSONUtil.parse(res, FileResponseBo.class);}}

前端使用Window.open就可以打开下载了