EasyExcel解析动态表头及导出

前言

excel文件导入及导出，是日常开发中经常遇到的需求。本次笔者以EasyExcel为例，针对在项目中遇到的动态表头解析及导出的场景，详细介绍具体的代码实现过程。

参考地址

https://github.com/alibaba/easyexcel

前端下载

const download = () => {axios({method: 'GET',url: config.http.baseUrl + '/templateDownload',responseType: 'blob',}).then(function (res) {const content = res.dataconst blob = new Blob([content], { type: "application/application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" })const downloadElement = document.createElement("a");const href = window.URL.createObjectURL(blob);downloadElement.href = href;downloadElement.download = decodeURI(res.headers['filename']);document.body.appendChild(downloadElement);downloadElement.click();document.body.removeChild(downloadElement); // 下载完成移除元素window.URL.revokeObjectURL(href); // 释放掉blob对象})}

模板下载

excel文件导入功能，常常需要进行模板下载，在springboot项目中，程序是以jar包的形式运行的，所以有很多小伙伴常常

遇到在本地开发中能够实现下载功能，但部署到服务器的时候，找不到模板文件的问题。

@Overridepublic void templateDownload(HttpServletResponse response, HttpServletRequest request) {//获取要下载的模板名称String fileName = "批量导入模板.xlsx";//获取文件下载路径String filePath = "/template/template.xlsx";TemplateDownloadUtil.download(response, request, fileName, filePath);}

import lombok.extern.slf4j.Slf4j;import org.springframework.core.io.ClassPathResource;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.InputStream;import java.io.OutputStream;import java.net.URLEncoder;/** * 模板文件下载工具类 * @author* @date 2021/05/20 9:20 */@Slf4jpublic class TemplateDownloadUtil {public static void download(HttpServletResponse response, HttpServletRequest request,String fileName,String filePath){try {response.setContentType("application/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response.setHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(fileName, "UTF-8"));response.setHeader("filename", URLEncoder.encode(fileName, "UTF-8"));response.setHeader("Access-Control-Expose-Headers", "filename,Content-Disposition");//获取文件的路径，此方式本地开发可以运行，服务器无法获取文件//String filePath = getClass().getResource("/template/template.xlsx").getPath();//FileInputStream input = new FileInputStream(filePath);//在服务器中能够读取到模板文件ClassPathResource resource = new ClassPathResource(filePath);InputStream input = resource.getInputStream();OutputStream out = response.getOutputStream();byte[] b = new byte[2048];int len;while ((len = input.read(b)) != -1) {out.write(b, 0, len);}//修正 Excel在“xxx.xlsx”中发现不可读取的内容。是否恢复此工作薄的内容？如果信任此工作簿的来源，请点击"是"//response.setHeader("Content-Length", String.valueOf(input.getChannel().size()));input.close();} catch (Exception e) {log.error("下载模板失败 :", e);}}}

EasyExcel动态表头解析

EasyExcel简单的读文件，官网中已经有详细的说明，本文不再赘述，详细操作参见

。

本文主要针对笔者遇到的复杂表头及动态表头进行讲解。

模板示例

解析

import com.alibaba.excel.context.AnalysisContext;import com.alibaba.excel.event.AnalysisEventListener;import com.alibaba.fastjson.JSON;import com.alibaba.fastjson.JSONObject;import lombok.Data;import lombok.extern.slf4j.Slf4j;import java.time.LocalDateTime;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import java.util.stream.Collectors;/** * 发薪单上传excel读取类 * * @author yupf * @description Listener 不能被spring管理，要每次读取excel都要new,然后里面用到spring可以构造方法传进去 */@Slf4j@Datapublic class BatchReadListener extends AnalysisEventListener<Map<Integer, String>> {/** * 每隔500条存储数据库，然后清理list ，方便内存回收 */private static final int BATCH_COUNT = 500;//Excel数据缓存结构private List<Map<Integer, Map<Integer, String>>> list = new ArrayList<>();//Excel表头（列名）数据缓存结构private Map<Integer, String> headTitleMap = new HashMap<>();/** * 假设这个是一个DAO，当然有业务逻辑这个也可以是一个service。当然如果不用存储这个对象没用。 */private DbFileBatchService dbFileBatchService;private DbFileContentService dbFileContentService;private FileBatch fileBatch;private int total = 0;/** * 如果使用了spring,请使用这个构造方法。每次创建Listener的时候需要把spring管理的类传进来 */public BatchReadListener(DbFileBatchService dbFileBatchService, DbFileContentService dbFileContentService, FileBatch fileBatch) {this.dbFileBatchService = dbFileBatchService;this.dbFileContentService = dbFileContentService;this.fileBatch = fileBatch;}/** * 这个每一条数据解析都会来调用 * * @param dataone row value. Is is same as {@link AnalysisContext#readRowHolder()} * @param context */@Overridepublic void invoke(Map<Integer, String> data, AnalysisContext context) {log.info("解析到一条数据:{}", JSON.toJSONString(data));total++;Map<Integer, Map<Integer, String>> map = new HashMap<>();map.put(context.readRowHolder().getRowIndex(), data);list.add(map);// 达到BATCH_COUNT了，需要去存储一次数据库，防止数据几万条数据在内存，容易OOMif (list.size() >= BATCH_COUNT) {saveData();// 存储完成清理 listlist.clear();}}/** * 所有数据解析完成了 都会来调用 * * @param context */@Overridepublic void doAfterAllAnalysed(AnalysisContext context) {// 这里也要保存数据，确保最后遗留的数据也存储到数据库saveData();log.info("所有数据解析完成！");}/** * 解析表头数据 **/@Overridepublic void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) {log.info("表头数据：{}", JSONObject.toJSONString(headMap));headTitleMap = headMap;}/** * 加上存储数据库 */private void saveData() {log.info("{}条数据，开始存储数据库！", list.size());FileContent fileContent = null;List<FileContent> fileContentList = list.stream().flatMap(integerMap -> integerMap.entrySet().stream().map(entrySet -> {//entrySet.getKey()获取的是内容的RowIndex,实际的行数需要根据表头数进行处理Integer rowIndex = entrySet.getKey();Map<Integer, String> value = entrySet.getValue();log.info(JSONObject.toJSONString(value));fileContent = new FileContent();fileContent.setBatchId(fileBatch.getId());fileContent.setBatchNo(fileBatch.getBatchNo());//固定字段入库fileContent.setName(value.get(0) != null " />.get(0).trim() : "");fileContent.setCertNo(value.get(1) != null ? value.get(1).trim() : "");fileContent.setRealAmount(value.get(2) != null ? value.get(2).trim() : "");//所有动态表头数据转为JSON串入库fileContent.setFieldsValue(JSONObject.toJSONString(value));//取实际的内容rowIndexfileContent.setRowNum(rowIndex + 1);fileContent.setCreateTime(LocalDateTime.now());return xcSalaryFileContent;})).collect(Collectors.toList());log.info(JSONObject.toJSONString(fileContentList));dbFileContentService.saveBatch(fileContentList);log.info("存储数据库成功！");}}

BatchReadListener listener = new BatchReadListener(dbFileBatchService, dbFileContentService, fileBatch);try {//注：headRowNumber默认为1，现赋值为2，即从第三行开始读取内容EasyExcel.read(fileInputStream, listener).headRowNumber(2).sheet().doRead();} catch (Exception e) {log.info("EasyExcel解析文件失败，{}", e);throw new CustomException("文件解析失败，请重新上传");}//获取表头信息进行处理Map<Integer, String> headTitleMap = listener.getHeadTitleMap();//获取动态表头信息List<String> headList = headTitleMap.keySet().stream().map(key -> {String head = headTitleMap.get(key);log.info(head);return head == null ? "" : head.replace("*", "");}).collect(Collectors.toList());//可以对表头进行入库保存，方便后续导出

综上，动态表头即可完成解析。

EasyExcel动态表头导出

导出示例

获取动态头

 private List<List<String>> getFileHeadList( FileBatch fileBatch) { String head = fileBatch.getFileHead(); List<String> headList = Arrays.asList(head.split(",")); List<List<String>> fileHead = headList.stream().map(item -> concatHead(Lists.newArrayList(item))).collect(Collectors.toList()); fileHead.add(concatHead(Lists.newArrayList("备注"))); return fileHead; }

/** * 填写须知 * @param headContent * @return */private List<String> concatHead(List<String> headContent) {String remake = "填写须知：\n" +"1.系统自动识别Excel表格，表头必须含有“企业账户号”、“企业账户名”、“实发金额”；\n" +"2.带 “*” 为必填字段，填写后才能上传成功；\n" +"3.若需上传其他表头，可自行在“实发金额”后添加表头，表头最多可添加20个，表头名称请控制在8个字以内；\n" +"4.填写的表头内容不可超过30个字；\n" +"5.实发金额支持填写到2位小数；\n" +"6.每次导入数据不超过5000条。\n" +"\n" +"注：请勿删除填写须知，删除后将导致文件上传失败\n" +"\n" +"表头示例：";headContent.add(0, remake);return headContent;}

获取数据

List<FileContent> fileContentList = dbFileContentService.list(Wrappers.<FileContent>lambdaQuery().eq(FileContent::getBatchId, fileBatch.getId()).orderByAsc(FileContent::getRowNum));List<List<Object>> contentList = fileContentList.stream().map(fileContent -> {List<Object> rowList = new ArrayList<>();String fieldsValue = fileContent.getFieldsValue();JSONObject contentObj = JSONObject.parseObject(fieldsValue);for (int columnIndex = 0 , length = headList.size(); columnIndex < length; columnIndex++) {Object content = contentObj.get(columnIndex);rowList.add(content == null " />"" : content);}rowList.add(fileContent.getCheckMessage());return rowList;}).collect(Collectors.toList());

单元格格式设置

import com.alibaba.excel.metadata.data.DataFormatData;import com.alibaba.excel.metadata.data.WriteCellData;import com.alibaba.excel.write.handler.context.CellWriteHandlerContext;import com.alibaba.excel.write.metadata.style.WriteCellStyle;import com.alibaba.excel.write.metadata.style.WriteFont;import com.alibaba.excel.write.style.HorizontalCellStyleStrategy;import org.apache.poi.ss.usermodel.BorderStyle;import org.apache.poi.ss.usermodel.HorizontalAlignment;import org.apache.poi.ss.usermodel.IndexedColors;import java.util.List;/** * 设置表头和填充内容的样式 */public class CellStyleStrategy extends HorizontalCellStyleStrategy {private final WriteCellStyle headWriteCellStyle;private final WriteCellStyle contentWriteCellStyle;/** * 操作列 */private final List<Integer> columnIndexes;public CellStyleStrategy(List<Integer> columnIndexes,WriteCellStyle headWriteCellStyle, WriteCellStyle contentWriteCellStyle) {this.columnIndexes = columnIndexes;this.headWriteCellStyle = headWriteCellStyle;this.contentWriteCellStyle = contentWriteCellStyle;}//设置头样式@Overrideprotected void setHeadCellStyle( CellWriteHandlerContext context) {// 获取字体实例WriteFont headWriteFont = new WriteFont();headWriteFont.setFontName("宋体");//表头不同处理if (columnIndexes.get(0).equals(context.getRowIndex())) {headWriteCellStyle.setFillForegroundColor(IndexedColors.WHITE.getIndex());headWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.LEFT);headWriteFont.setFontHeightInPoints((short) 12);headWriteFont.setBold(false);headWriteFont.setFontName("宋体");}else{headWriteCellStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());headWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);headWriteFont.setFontHeightInPoints((short) 11);headWriteFont.setBold(false);headWriteFont.setFontName("微软雅黑");}headWriteCellStyle.setWriteFont(headWriteFont);DataFormatData dataFormatData = new DataFormatData();dataFormatData.setIndex((short)49);headWriteCellStyle.setDataFormatData(dataFormatData);if (stopProcessing(context)) {return;}WriteCellData<?> cellData = context.getFirstCellData();WriteCellStyle.merge(headWriteCellStyle, cellData.getOrCreateStyle());}//设置填充数据样式@Overrideprotected void setContentCellStyle(CellWriteHandlerContext context) {WriteFont contentWriteFont = new WriteFont();contentWriteFont.setFontName("宋体");contentWriteFont.setFontHeightInPoints((short) 11);//设置数据填充后的实线边框contentWriteCellStyle.setWriteFont(contentWriteFont);contentWriteCellStyle.setBorderLeft(BorderStyle.THIN);contentWriteCellStyle.setBorderTop(BorderStyle.THIN);contentWriteCellStyle.setBorderRight(BorderStyle.THIN);contentWriteCellStyle.setBorderBottom(BorderStyle.THIN);DataFormatData dataFormatData = new DataFormatData();dataFormatData.setIndex((short)49);contentWriteCellStyle.setDataFormatData(dataFormatData);contentWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);WriteCellData<?> cellData = context.getFirstCellData();WriteCellStyle.merge(contentWriteCellStyle, cellData.getOrCreateStyle());}}

行高设置

import com.alibaba.excel.write.style.row.AbstractRowHeightStyleStrategy;import org.apache.poi.ss.usermodel.Row;/** * 设置表头的自动调整行高策略 */public class CellRowHeightStyleStrategy extends AbstractRowHeightStyleStrategy {@Overrideprotected void setHeadColumnHeight(Row row, int relativeRowIndex) {//设置主标题行高为17.7if(relativeRowIndex == 0){//如果excel需要显示行高为15，那这里就要设置为15*20=300row.setHeight((short) 3240);}}@Overrideprotected void setContentColumnHeight(Row row, int relativeRowIndex) {}}

列宽度自适应

如果是简单表头，可以使用EasyExcel中的LongestMatchColumnWidthStyleStrategy()来实现。

EasyExcel.write(fileName, LongestMatchColumnWidthData.class).registerWriteHandler(new LongestMatchColumnWidthStyleStrategy()).sheet("模板").doWrite(dataLong());

如果是复杂表头，就需要自己来实现，代码如下：

import com.alibaba.excel.enums.CellDataTypeEnum;import com.alibaba.excel.metadata.Head;import com.alibaba.excel.metadata.data.CellData;import com.alibaba.excel.metadata.data.WriteCellData;import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;import com.alibaba.excel.write.style.column.AbstractColumnWidthStyleStrategy;import lombok.extern.slf4j.Slf4j;import org.apache.commons.collections.CollectionUtils;import org.apache.poi.ss.usermodel.Cell;import java.util.HashMap;import java.util.List;import java.util.Map;/** * @author yupf * @description * @date 2022/9/7 18:48 */@Slf4jpublic class CellWidthStyleStrategy extends AbstractColumnWidthStyleStrategy {private Map<Integer, Map<Integer, Integer>> CACHE = new HashMap<>();@Overrideprotected void setColumnWidth(WriteSheetHolder writeSheetHolder, List<WriteCellData<?>> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {Map<Integer, Integer> maxColumnWidthMap = CACHE.get(writeSheetHolder.getSheetNo());if (maxColumnWidthMap == null) {maxColumnWidthMap = new HashMap<>();CACHE.put(writeSheetHolder.getSheetNo(), maxColumnWidthMap);}if (isHead) {if(relativeRowIndex.intValue() == 1){Integer length = cell.getStringCellValue().getBytes().length;Integer maxColumnWidth = maxColumnWidthMap.get(cell.getColumnIndex());if (maxColumnWidth == null || length > maxColumnWidth) {maxColumnWidthMap.put(cell.getColumnIndex(), length);writeSheetHolder.getSheet().setColumnWidth(cell.getColumnIndex(), length * 300);}}}else{Integer columnWidth = this.dataLength(cellDataList, cell, isHead);if (columnWidth >= 0) {if (columnWidth > 255) {columnWidth = 255;}Integer maxColumnWidth = maxColumnWidthMap.get(cell.getColumnIndex());if (maxColumnWidth == null || columnWidth > maxColumnWidth) {maxColumnWidthMap.put(cell.getColumnIndex(), columnWidth);writeSheetHolder.getSheet().setColumnWidth(cell.getColumnIndex(), columnWidth * 256);}}}}private Integer dataLength(List<WriteCellData<?>> cellDataList, Cell cell, Boolean isHead) {if (isHead) {return cell.getStringCellValue().getBytes().length;} else {CellData cellData = cellDataList.get(0);CellDataTypeEnum type = cellData.getType();if (type == null) {return -1;} else {switch (type) {case STRING:return cellData.getStringValue().getBytes().length;case BOOLEAN:return cellData.getBooleanValue().toString().getBytes().length;case NUMBER:return cellData.getNumberValue().toString().getBytes().length;default:return -1;}}}}}

写入文件

EasyExcel.write(response.getOutputStream()).head(head).registerWriteHandler(new CellRowHeightStyleStrategy()) //设置行高的策略.registerWriteHandler(new CellStyleStrategy(Arrays.asList(0,1),new WriteCellStyle(), new WriteCellStyle())).registerWriteHandler(new CellWidthStyleStrategy()).sheet(sheetName).doWrite(list);

总结

以上便是EasyExcel解析动态表头及导出的整个过程。

在使用过程中，笔者的感受是，上手难度很低，很适合新手去做简单的表格解析，当然，如果你的需求有复杂的格式，EasyExcel也提供了api，能够很好的满足需要。