Java怎么用EasyExcel解析动态表头并导出

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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;@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。

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;@Slf4j@Datapublic class BatchReadListener extends AnalysisEventListener<Map<Integer, String>> {        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<>();        private DbFileBatchService dbFileBatchService;    private DbFileContentService dbFileContentService;    private FileBatch fileBatch;    private int total = 0;        public BatchReadListener(DbFileBatchService dbFileBatchService, DbFileContentService dbFileContentService, FileBatch fileBatch) {        this.dbFileBatchService = dbFileBatchService;        this.dbFileContentService = dbFileContentService;        this.fileBatch = fileBatch;    }        @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，需要去存储一次数据库，防止数据几万条数据在内存，容易OOM        if (list.size() >= BATCH_COUNT) {            saveData();            // 存储完成清理 list            list.clear();        }    }        @Override    public 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！");    }        @Override    public void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) {        log.info("表头数据：{}", JSONObject.toJSONString(headMap));        headTitleMap = headMap;    }        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 ? value.get(0).trim() : "");                fileContent.setCertNo(value.get(1) != null ? value.get(1).trim() : "");                fileContent.setRealAmount(value.get(2) != null ? value.get(2).trim() : "");                //所有动态表头数据转为JSON串入库                fileContent.setFieldsValue(JSONObject.toJSONString(value));                //取实际的内容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;     }

    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;public class CellStyleStrategy extends HorizontalCellStyleStrategy {    private final WriteCellStyle headWriteCellStyle;    private final WriteCellStyle contentWriteCellStyle;        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    @Override    protected 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    @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;public class CellRowHeightStyleStrategy extends AbstractRowHeightStyleStrategy {    @Override    protected void setHeadColumnHeight(Row row, int relativeRowIndex) {        //设置主标题行高为17.7        if(relativeRowIndex == 0){            //如果excel需要显示行高为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;@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);

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