前言
excel文件导入及导出，是日常开发中常常遇到的需要。本次笔者以EasyExcel为例，针对在我的项目中遇到的动静表头解析及导出的场景，具体介绍具体的代码实现过程。
参考地址
https://github.com/alibaba/ea...
前端下载
const download = () => { axios({ method: 'GET', url: config.http.baseUrl + '/templateDownload', responseType: 'blob', }) .then(function (res) { const content = res.data const 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); // 下载实现移除元素 window.URL.revokeObjectURL(href); // 开释掉blob对象 }) }模板下载
excel文件导入性能，经常须要进行模板下载，在springboot我的项目中，程序是以jar包的模式运行的，所以有很多小伙伴经常
遇到在本地开发中可能实现下载性能，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"; //获取文件下载门路 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能够避免中文乱码 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"); //获取文件的门路，此形式本地开发能够运行，服务器无奈获取文件// String filePath = getClass().getResource("/template/template.xlsx").getPath();// FileInputStream input = new FileInputStream(filePath); //在服务器中可能读取到模板文件 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); } //修改 Excel在“xxx.xlsx”中发现不可读取的内容。是否复原此工作薄的内容？如果信赖此工作簿的起源，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动静表头解析
EasyExcel简略的读文件，官网中曾经有具体的阐明，本文不再赘述，具体操作参见官网。
本文次要针对笔者遇到的简单表头及动静表头进行解说。
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治理，要每次读取excel都要new,而后外面用到spring能够构造方法传进去 */@Slf4j@Datapublic class BatchReadListener extends AnalysisEventListener<Map<Integer, String>> { /** * 每隔500条存储数据库，而后清理list ，不便内存回收 */ private static final int BATCH_COUNT = 500; //Excel数据缓存构造 private List<Map<Integer, Map<Integer, String>>> list = new ArrayList<>(); //Excel表头（列名）数据缓存构造 private Map<Integer, String> headTitleMap = new HashMap<>(); /** * 假如这个是一个DAO，当然有业务逻辑这个也能够是一个service。当然如果不必存储这个对象没用。 */ private DbFileBatchService dbFileBatchService; private DbFileContentService dbFileContentService; private FileBatch fileBatch; private int total = 0; /** * 如果应用了spring,请应用这个构造方法。每次创立Listener的时候须要把spring治理的类传进来 */ 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 data one row value. Is is same as {@link AnalysisContext#readRowHolder()} * @param context */ @Override public 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，须要去存储一次数据库，避免数据几万条数据在内存，容易OOM if (list.size() >= BATCH_COUNT) { saveData(); // 存储实现清理 list list.clear(); } } /** * 所有数据解析实现了 都会来调用 * * @param context */ @Override public void doAfterAllAnalysed(AnalysisContext context) { // 这里也要保留数据，确保最初遗留的数据也存储到数据库 saveData(); log.info("所有数据解析实现！"); } /** * 解析表头数据 **/ @Override public 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,理论的行数须要依据表头数进行解决 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 ? value.get(0).trim() : ""); fileContent.setCertNo(value.get(1) != null ? value.get(1).trim() : ""); fileContent.setRealAmount(value.get(2) != null ? value.get(2).trim() : ""); //所有动静表头数据转为JSON串入库 fileContent.setFieldsValue(JSONObject.toJSONString(value)); //取理论的内容rowIndex fileContent.setRowNum(rowIndex + 1); fileContent.setCreateTime(LocalDateTime.now()); return xcSalaryFileContent; } )).collect(Collectors.toList()); log.info(JSONObject.toJSONString(fileContentList)); dbFileContentService.saveBatch(fileContentList); log.info("存储数据库胜利！"); }} 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，请从新上传"); } //获取表头信息进行解决 Map<Integer, String> headTitleMap = listener.getHeadTitleMap(); //获取动静表头信息 List<String> headList = headTitleMap.keySet().stream().map(key -> { String head = headTitleMap.get(key); log.info(head); return head == null ? "" : head.replace("*", ""); }).collect(Collectors.toList()); //能够对表头进行入库保留，不便后续导出综上，动静表头即可实现解析。
EasyExcel动静表头导出
导出示例
获取动静头
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" + "1.零碎自动识别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，填写后能力上传胜利；\n" + "3.若需上传其余表头，可自行在“实发金额”后增加表头，表头最多可增加20个，表头名称请管制在8个字以内；\n" + "4.填写的表头内容不可超过30个字；\n" + "5.实发金额反对填写到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());单元格格局设置
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款式 */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; } //设置头款式 @Override protected void setHeadCellStyle( CellWriteHandlerContext context) { // 获取字体实例 WriteFont headWriteFont = new WriteFont(); headWriteFont.setFontName("宋体"); //表头不同解决 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()); } //设置填充数据款式 @Override protected 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;/** * 设置表头的主动调整行高策略 */public class CellRowHeightStyleStrategy extends AbstractRowHeightStyleStrategy { @Override protected void setHeadColumnHeight(Row row, int relativeRowIndex) { //设置主题目行高为17.7 if(relativeRowIndex == 0){ //如果excel须要显示行高为15，那这里就要设置为15*20=300 row.setHeight((short) 3240); } } @Override protected void setContentColumnHeight(Row row, int relativeRowIndex) { }}列宽度自适应
如果是简略表头，能够应用EasyExcel中的LongestMatchColumnWidthStyleStrategy()来实现。
EasyExcel.write(fileName, LongestMatchColumnWidthData.class) .registerWriteHandler(new LongestMatchColumnWidthStyleStrategy()).sheet("模板").doWrite(dataLong());如果是简单表头，就须要本人来实现，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<>(); @Override protected 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解析动静表头及导出的整个过程。
在应用过程中，笔者的感触是，上手难度很低，很适宜老手去做简略的表格解析，当然，如果你的需要有简单的格局，EasyExcel也提供了api，可能很好的满足需要。