使用FastExcel数据导出：官网： https://idev.cn/fastexcel/zh-CN

需求

信用代码、填报人，唯一时，将：信用代码、单位名称、填报人，进行 row 合并，并垂直居中对齐 。

思路

这边不需要做列合并，所以采用了 RowWriteHandler 思路， 。

• 指定唯一值，根据某个或多个单元格确定相当的数据行（代码中的 ExcelCellMergeStrategy. uniqueCol）
• 判断当前行的唯一列的数据和上一行是否相等，如果相等继续，要合并的行数 mergeCount + 1
• 如果当前行和上一行不相等，说明前面的数据需要做合并处理了。同时将当前行做为下一次待合并的起始行

实现

Excel导出单元格全量合并策略

package com.vipsoft.handler;


import cn.idev.excel.write.handler.RowWriteHandler;
import cn.idev.excel.write.metadata.holder.WriteSheetHolder;
import cn.idev.excel.write.metadata.holder.WriteTableHolder;

import org.apache.poi.ss.usermodel.*;

import org.apache.poi.ss.util.CellRangeAddress;

import java.util.ArrayList;
import java.util.List;

/**
 * Excel导出单元格全量合并策略
 */
public class ExcelCellMergeStrategy implements RowWriteHandler {

    private int mergeRowIndex;//从哪一行开始合并
    private List<Integer> mergeColumnIndex = new ArrayList<>();//excel合并的列
    private int[] uniqueCol;//合并的唯一标识，根据指定的列，确定数据是否相同
    private int totalRow;//总行数

    private int lastRow;
    private int firstCol;
    private int lastCol;
    private int firstRow;

    private int mergeCount = 1;

    /**
     * @param mergeRowIndex
     * @param mergeColIndex 支持范围如：0-3,6,9
     * @param uniqueCol     唯一标识，1列或多列 数据组成唯一值
     * @param totalRow      总行数(从0开始）：List.size -1  + 跳过的表头
     */
    public ExcelCellMergeStrategy(int mergeRowIndex, Object[] mergeColIndex, int[] uniqueCol, int totalRow) {
        this.mergeRowIndex = mergeRowIndex;
        for (Object item : mergeColIndex) {
            if (item.toString().contains("-")) {
                String[] spCol = item.toString().split("-");
                int start = Integer.parseInt(spCol[0]);
                int end = Integer.parseInt(spCol[1]);
                for (int i = start; i <= end; i++) {
                    mergeColumnIndex.add(i);
                }
            } else {
                int colIndex = Integer.parseInt(item.toString());
                mergeColumnIndex.add(colIndex);
            }

        }
        this.uniqueCol = uniqueCol;
        this.totalRow = totalRow;
    }

    @Override
    public void beforeRowCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Integer rowIndex, Integer relativeRowIndex, Boolean isHead) {

    }

    @Override
    public void afterRowCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row, Integer relativeRowIndex, Boolean isHead) {

    }

    @Override
    public void afterRowDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row, Integer relativeRowIndex, Boolean isHead) {
        //当前行
        int curRowIndex = row.getRowNum();
        //每一行的最大列数
        short lastCellNum = row.getLastCellNum();
        //当前行为开始合并行时，标记
        if (curRowIndex == mergeRowIndex) {
            //赋初值 第一行
            firstRow = curRowIndex;
        }
        //开始合并位置
        if (curRowIndex > mergeRowIndex && !row.getCell(0).getStringCellValue().equals("")) {
            for (int i = 0; i < lastCellNum; i++) {
                if (mergeColumnIndex.contains(i)) {
                    //当前行号 当前行对象 合并的标识位
                    mergeWithPrevAnyRow(writeSheetHolder.getSheet(), curRowIndex, row, uniqueCol);
                    break;//已经进入到合并单元格操作里面了，执行一次就行
                }

            }
        }
    }

    public void mergeWithPrevAnyRow(Sheet sheet, int curRowIndex, Row row, int[] uniqueCol) {
        Object currentData = "";
        Object preData = "";
        for (int col : uniqueCol) {
            currentData = currentData + row.getCell(col).getStringCellValue();
            Row preRow = row.getSheet().getRow(curRowIndex - 1);
            preData = preData + preRow.getCell(col).getStringCellValue();
        }

        //判断是否合并单元格
        boolean curEqualsPre = currentData.equals(preData);
        //判断前一个和后一个相同 并且 标识位相同
        if (curEqualsPre) {
            lastRow = curRowIndex;
            mergeCount++;
        }
        //excel过程中合并
        if (!curEqualsPre && mergeCount > 1) {
            mergeSheet(firstRow, lastRow, mergeColumnIndex, sheet);
            mergeCount = 1;
        }

        //excel结尾处合并
        if (mergeCount > 1 && totalRow == curRowIndex) {
            mergeSheet(firstRow, lastRow, mergeColumnIndex, sheet);
            mergeCount = 1;
        }
        //重置下一个要合并的行
        if (!curEqualsPre) {
            firstRow = curRowIndex;
        }

    }

    private void mergeSheet(int firstRow, int lastRow, List<Integer> mergeColumnIndex, Sheet sheet) {
        for (int colNum : mergeColumnIndex) {
            firstCol = colNum;
            lastCol = colNum;
            CellRangeAddress cellRangeAddress = new CellRangeAddress(firstRow, lastRow, firstCol, lastCol);
            sheet.addMergedRegion(cellRangeAddress);

            // 设置合并后的单元格样式为垂直居中
            CellStyle style = sheet.getWorkbook().createCellStyle();
            style.setVerticalAlignment(VerticalAlignment.CENTER);
            //style.setAlignment(HorizontalAlignment.CENTER);
            Cell mergedCell = sheet.getRow(firstRow).getCell(colNum, Row.MissingCellPolicy.CREATE_NULL_AS_BLANK);
            mergedCell.setCellStyle(style);
        }
    }
}

日期格式转换

EasyExcel => FastExcel ，导入支持多种时间格式 。

package com.vipsoft.base.util;

import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;

import cn.idev.excel.converters.Converter;
import cn.idev.excel.enums.CellDataTypeEnum;
import cn.idev.excel.metadata.GlobalConfiguration;
import cn.idev.excel.metadata.data.ReadCellData;
import cn.idev.excel.metadata.data.WriteCellData;
import cn.idev.excel.metadata.property.ExcelContentProperty;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 日期格式转换器
 */
public class ExcelDateConverter implements Converter<Date> {
    private static final Logger log = LoggerFactory.getLogger(ExcelDateConverter.class);
    // 定义所有要尝试的日期格式
    SimpleDateFormat[] formats = {
            new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"),
            new SimpleDateFormat("yyyy/MM/dd HH:mm:ss"),
            new SimpleDateFormat("yyyy/MM/dd"),
            new SimpleDateFormat("yyyy-MM-dd"),
            new SimpleDateFormat("yyyy-MM"),
            new SimpleDateFormat("yyyy/MM"),
            new SimpleDateFormat("yyyyMMdd")
    };

    @Override
    public Class<Date> supportJavaTypeKey() {
        return Date.class;
    }

    @Override
    public CellDataTypeEnum supportExcelTypeKey() {
        return CellDataTypeEnum.STRING;
    }


    @Override
    public Date convertToJavaData(ReadCellData<?> cellData, ExcelContentProperty contentProperty,
                                  GlobalConfiguration globalConfiguration) throws Exception {
        String cellValue = "";
        if (cellData.getType().equals(CellDataTypeEnum.NUMBER)) {
            long cellIntValue = cellData.getNumberValue().longValue();
            if (cellIntValue > 19900100) {
                try {
                    // 1. 第一种解析，传入的是数字形式的日期，形如yyyyMMdd
                    SimpleDateFormat originalFormat = new SimpleDateFormat("yyyyMMdd");
                    return originalFormat.parse(String.valueOf(cellIntValue));
                } catch (Exception e) {
                    log.warn("exception when parse numerical time with format yyyyMMdd");
                    cellValue=String.valueOf(cellIntValue);
                }
            }

            // 2. 第二种解析， excel是从1900年开始计算,最终通过计算与1900年间隔的天数计算目标日期
            LocalDate localDate = LocalDate.of(1900, 1, 1);

            //excel 有些奇怪的bug, 导致日期数差2
            localDate = localDate.plusDays(cellIntValue - 2);

            // 转换为ZonedDateTime（如果需要时区信息）
            ZonedDateTime zonedDateTime = localDate.atStartOfDay(ZoneId.systemDefault());
            return Date.from(zonedDateTime.toInstant());
        } else if (cellData.getType().equals(CellDataTypeEnum.STRING)) {
            // 3. 第三种解析
            Date date = null;
            cellValue = cellData.getStringValue();
            for (SimpleDateFormat format : formats) {
                try {
                    date = format.parse(cellValue);
                    if (date != null) {
                        // 这一步是将日期格式化为Java期望的格式
                        return date;
                    }
                } catch (Exception e) {
                    // 如果有异常，捕捉异常后继续解析
                    //log.error(e.getMessage(), e);
                }
            }
        }
        // 没转成功，抛出异常
        throw new UnsupportedOperationException("The current operation is not supported by the current converter." + cellValue);
    }


    @Override
    public WriteCellData<?> convertToExcelData(Date value, ExcelContentProperty contentProperty, GlobalConfiguration globalConfiguration) throws Exception {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        String dateValue = sdf.format(value);
        return new WriteCellData<>(dateValue);
    }
} 

接口代码

导出代码 。

package com.vipsoft.api.controller;

import cn.hutool.core.util.ObjectUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.InputStream;
import java.util.Map;

/**
 * 企业信息
 */
@RestController
@RequestMapping("/detail")
public class CooperationDetailController extends BaseController {


  /**
     * 企业信息
     * 
     * @return
     */
    @PostMapping("/export")
    public void exportInfo(HttpServletRequest request, HttpServletResponse response, @RequestBody Map<String, Object> param) {
        try {
            Page page = buildPage(param, CooperationInfo.class);
            QueryWrapper<SysOrganization> queryWrapper = buildQueryWrapper(SysOrganization.class, param);            
            cooperationDetailService.exportInfo(response, queryWrapper);
        } catch (Exception ex) {
            logger.error(ex.getMessage(), ex);
        }
    }
}

Service

@Service
public class SysOrganizationServiceImpl extends ServiceImpl<SysOrganizationMapper, SysOrganization> implements ISysOrganizationService {

    @Override
    public void exportInfo(HttpServletResponse response, QueryWrapper<SysOrganization> queryWrapper) {
        String templateFileName = "";
        try {
            templateFileName = cuworConfig.getFilePath() + "/template/企业导出模板.xlsx";
            response.setContentType("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 FastExcel 没有关系
            String fileName = URLEncoder.encode("企业数据", "UTF-8").replaceAll("\\+", "%20");
            response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");
            //获取要导出的数据 DTO
            List<SysOrganizationExcelDTO> dataList = data(queryWrapper);
            int mergeRowIndex = 2;                      // 从那一行开始合并  -- 跳过表头
            int[] uniqueCol = {0, 7};                  //根据指定的列，确定相同的数据
            Object[] mergeColIndex = {"0-1", 6, 7};    //需要合并的列
            int totalRow = dataList.size() - 1 + mergeRowIndex;
            // 这里需要设置不关闭流
            ExcelCellMergeStrategy excelCellMergeStrategy = new ExcelCellMergeStrategy(mergeRowIndex, mergeColIndex, uniqueCol, totalRow);
            FastExcel.write(response.getOutputStream(), SysOrganizationExcelDTO.class)
                    .needHead(false)
                    .withTemplate(templateFileName)
                    .autoCloseStream(Boolean.FALSE)
                    .registerWriteHandler(excelCellMergeStrategy) //合并单元格
                    .sheet("企业数据")
                    .doWrite(dataList);
        } catch (Exception e) {
            // 重置response
            response.reset();
            response.setContentType("application/json");
            response.setCharacterEncoding("utf-8");
            //异常时，向前端抛出 JSON 
            ApiResult result = new ApiResult(6001, "下载文件失败 " + templateFileName + " " + e.getMessage());
            try {
                response.getWriter().println(PojoUtil.pojoToJson(result));
            } catch (IOException ex) {
                logger.error(ex.getMessage(), ex);
                throw new CustomException(ex.getMessage());
            }
        }
    }

    /**
     * 获得要到出的数据
     */
    private List<SysOrganizationExcelDTO> data(QueryWrapper<SysOrganization>  queryWrapper) {
        IPage list = this.page(new Page(1, 10000), queryWrapper);
        List<SysOrganizationExcelDTO> result = new ArrayList<>();
        for (Object obj : list.getRecords()) {
            if (obj instanceof SysOrganization) {
                SysOrganization item = (SysOrganization) obj;
                SysOrganizationExcelDTO info = new SysOrganizationExcelDTO(); 
                BeanUtils.copyProperties(item, info); 
                //组装数据
                result.add(info);
            }
        }
        return result;
    }
}  

DTO

package com.vipsoft.base.dto;


import cn.idev.excel.annotation.ExcelIgnore;
import cn.idev.excel.annotation.ExcelProperty;
import cn.idev.excel.annotation.format.DateTimeFormat;
import com.vipsoft.base.util.ExcelDateConverter;

import java.io.Serializable;
import java.util.Date;

/**
 * Excel 导出使用
 */
public class SysOrganizationExcelDTO implements Serializable {

    /**
     * 统一社会信用代码
     */
    //@ExcelProperty(value = "统一社会信用代码")
    @ExcelProperty(index = 0)
    private String unifiedSocialCode;

    /**
     * 机构名称
     */
    @ExcelProperty(index = 1)
    private String orgName; 

    /**
     * 岗位大类名称
     */
    @ExcelProperty(index = 2)
    private String jobBigName;
    /**
     * 岗位中类名称
     */
    @ExcelProperty(index = 3)
    private String jobMiddleName;
    /**
     * 岗位小类名称
     */
    @ExcelProperty(index = 4)
    private String jobSmallName;
    /**
     * 岗位数量
     */
    @ExcelProperty(index = 5)
    private Integer jobQty;
	
    /**
     * 填报日期*
     */
    @ExcelProperty(index = 6, converter = ExcelDateConverter.class)
    private Date inputDate;
    /**
     * 填报人
     */
    @ExcelProperty(index = 7)
    private String inputUser;

    ......省略get set
 
}

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