EasyExcel解析合并的单元格

注意@ExcelProperty需要设置index，原理是，合并的单元格只有合并区域的第一行第一列有值，其他单元格为null，通过循环合并区域，填充为合并区域第一行第一列单元格的值。

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.alibaba.excel.metadata.CellExtra;
import com.alibaba.fastjson.JSON;
import com.walltech.rpc.common.errorcode.BaseErrorCode;
import com.walltech.rpc.common.exception.ErrorCodeException;
import lombok.extern.slf4j.Slf4j;
import java.util.ArrayList;
import java.util.List;
/**
 * @author mori
 * @date 2022/7/29
 */
@Slf4j
public class UploadDataListener<T> extends AnalysisEventListener<T> {
    /**
     * 解析的数据
     */
    private final List<T> list = new ArrayList<>();
    /**
     * 正文起始行
     */
    private final Integer headRowNumber;
    /**
     * 合并单元格
     */
    private final List<CellExtra> extraMergeInfoList = new ArrayList<>();
    public UploadDataListener(Integer headRowNumber) {
        this.headRowNumber = headRowNumber;
    }
    /**
     * 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 context
     */
    @Override
    public void invoke(T data, AnalysisContext context) {
        Integer rowIndex = context.readRowHolder().getRowIndex();
        log.info("rowIndex:{}, 解析到一条数据:{}", rowIndex, JSON.toJSONString(data));
        list.add(data);
    }
    /**
     * 所有数据解析完成了 都会来调用
     *
     * @param context context
     */
    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {
        log.info("所有数据解析完成！");
    }
    /**
     * 加上存储数据库
     */
    public List<T> getData() {
        return list;
    }
    @Override
    public void extra(CellExtra extra, AnalysisContext context) {
        log.info("读取到了一条额外信息:{}", JSON.toJSONString(extra));
        switch (extra.getType()) {
            case COMMENT: {
                log.info("额外信息是批注,在rowIndex:{},columnIndex;{},内容是:{}", extra.getRowIndex(), extra.getColumnIndex(),
                        extra.getText());
                break;
            }
            case HYPERLINK: {
                if ("Sheet1!A1".equals(extra.getText())) {
                    log.info("额外信息是超链接,在rowIndex:{},columnIndex;{},内容是:{}", extra.getRowIndex(),
                            extra.getColumnIndex(), extra.getText());
                } else if ("Sheet2!A1".equals(extra.getText())) {
                    log.info(
                            "额外信息是超链接,而且覆盖了一个区间,在firstRowIndex:{},firstColumnIndex;{},lastRowIndex:{},lastColumnIndex:{},"
                                    + "内容是:{}",
                            extra.getFirstRowIndex(), extra.getFirstColumnIndex(), extra.getLastRowIndex(),
                            extra.getLastColumnIndex(), extra.getText());
                } else {
                    log.error("Unknown hyperlink!");
                    throw new ErrorCodeException(BaseErrorCode.FILE_HANDLE_ERROR);
                }
                break;
            }
            case MERGE: {
                log.info(
                        "额外信息是合并单元格,而且覆盖了一个区间,在firstRowIndex:{},firstColumnIndex;{},lastRowIndex:{},lastColumnIndex:{}",
                        extra.getFirstRowIndex(), extra.getFirstColumnIndex(), extra.getLastRowIndex(),
                        extra.getLastColumnIndex());
                if (extra.getRowIndex() >= headRowNumber) {
                    extraMergeInfoList.add(extra);
                }
                break;
            }
            default: {
            }
        }
    }
    public List<CellExtra> getExtraMergeInfoList() {
        return extraMergeInfoList;
    }
}

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.enums.CellExtraTypeEnum;
import com.alibaba.excel.metadata.CellExtra;
import com.walltech.etower.listener.UploadDataListener;
import com.walltech.rpc.common.errorcode.BaseErrorCode;
import com.walltech.rpc.common.exception.ErrorCodeException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.CollectionUtils;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.util.List;
/**
 * @author mori
 * @date 2022/7/29
 */
@Slf4j
public class ExcelAnalysisHelper<T> {
    public List<T> getList(InputStream fileStream, Class<T> clazz) {
        return getList(fileStream, clazz, 0, 1);
    }
    public List<T> getList(InputStream fileStream, Class<T> clazz, Integer sheetNo, Integer headRowNumber) {
        UploadDataListener<T> listener = new UploadDataListener<>(headRowNumber);
        try {
            EasyExcel.read(fileStream, clazz, listener).extraRead(CellExtraTypeEnum.MERGE).sheet(sheetNo).headRowNumber(headRowNumber).doRead();
            List<CellExtra> extraMergeInfoList = listener.getExtraMergeInfoList();
            List<T> data = listener.getData();
            if (CollectionUtils.isEmpty(extraMergeInfoList) || CollectionUtils.isEmpty(data)) {
                return data;
            }
            return explainMergeData(data, extraMergeInfoList, headRowNumber);
        } catch (Exception e) {
            log.error("EasyExcel analysis file error.", e);
            throw new ErrorCodeException(BaseErrorCode.FILE_HANDLE_ERROR);
        }
    }
    /**
     * 处理合并单元格
     *
     * @param data               解析数据
     * @param extraMergeInfoList 合并单元格信息
     * @param headRowNumber      起始行
     * @return 填充好的解析数据
     */
    private List<T> explainMergeData(List<T> data, List<CellExtra> extraMergeInfoList, Integer headRowNumber) {
        // 循环所有合并单元格信息
        extraMergeInfoList.forEach(cellExtra -> {
            int firstRowIndex = cellExtra.getFirstRowIndex() - headRowNumber;
            int lastRowIndex = cellExtra.getLastRowIndex() - headRowNumber;
            int firstColumnIndex = cellExtra.getFirstColumnIndex();
            int lastColumnIndex = cellExtra.getLastColumnIndex();
            // 获取初始值
            Object initValue = getInitValueFromList(firstRowIndex, firstColumnIndex, data);
            // 设置值
            for (int i = firstRowIndex; i <= lastRowIndex; i++) {
                for (int j = firstColumnIndex; j <= lastColumnIndex; j++) {
                    setInitValueToList(initValue, i, j, data);
                }
            }
        });
        return data;
    }
    /**
     * 设置合并单元格的值
     *
     * @param filedValue  值
     * @param rowIndex    行
     * @param columnIndex 列
     * @param data        解析数据
     */
    public void setInitValueToList(Object filedValue, Integer rowIndex, Integer columnIndex, List<T> data) {
        T object = data.get(rowIndex);
        for (Field field : object.getClass().getDeclaredFields()) {
            field.setAccessible(true);
            ExcelProperty annotation = field.getAnnotation(ExcelProperty.class);
            if (annotation != null) {
                if (annotation.index() == columnIndex) {
                    try {
                        field.set(object, filedValue);
                        break;
                    } catch (IllegalAccessException e) {
                        throw new ErrorCodeException(BaseErrorCode.FILE_HANDLE_ERROR);
                    }
                }
            }
        }
    }
    /**
     * 获取合并单元格的初始值
     * rowIndex对应list的索引
     * columnIndex对应实体内的字段
     *
     * @param firstRowIndex    起始行
     * @param firstColumnIndex 起始列
     * @param data             列数据
     * @return 初始值
     */
    private Object getInitValueFromList(Integer firstRowIndex, Integer firstColumnIndex, List<T> data) {
        int size = data.size();
        if (firstRowIndex > size - 1) {
            // 不支持空行
            throw new ErrorCodeException(BaseErrorCode.FILE_HANDLE_ERROR);
        }
        Object fieldValue = null;
        T object = data.get(firstRowIndex);
        for (Field field : object.getClass().getDeclaredFields()) {
            field.setAccessible(true);
            ExcelProperty annotation = field.getAnnotation(ExcelProperty.class);
            if (annotation != null) {
                if (annotation.index() == firstColumnIndex) {
                    try {
                        fieldValue = field.get(object);
                        break;
                    } catch (IllegalAccessException e) {
                        throw new ErrorCodeException(BaseErrorCode.FILE_HANDLE_ERROR);
                    }
                }
            }
        }
        return fieldValue;
    }
}