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Simplify the operating components of excel with Alibaba's easyexcel
/*
* Copyright (C) 2022 [www.mobaijun.com]
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.mobaijun.easyexcel.core;
import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.util.StrUtil;
import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.write.handler.WorkbookWriteHandler;
import com.alibaba.excel.write.handler.context.WorkbookWriteHandlerContext;
import com.alibaba.excel.write.merge.AbstractMergeStrategy;
import com.mobaijun.core.util.reflect.ReflectUtil;
import com.mobaijun.easyexcel.annotation.CellMerge;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.util.CellRangeAddress;
/**
* Description: 列值重复合并策略
* Author: [mobaijun]
* Date: [2024/8/20 18:20]
* IntelliJ IDEA Version: [IntelliJ IDEA 2023.1.4]
*/
@Slf4j
public class CellMergeStrategy extends AbstractMergeStrategy implements WorkbookWriteHandler {
private final List cellList;
private int rowIndex;
public CellMergeStrategy(List list, boolean hasTitle) {
// 行合并开始下标
this.rowIndex = hasTitle ? 1 : 0;
this.cellList = handle(list, hasTitle);
}
@Override
protected void merge(Sheet sheet, Cell cell, Head head, Integer relativeRowIndex) {
//单元格写入了,遍历合并区域,如果该Cell在区域内,但非首行,则清空
final int rowIndex = cell.getRowIndex();
if (CollUtil.isNotEmpty(cellList)) {
for (CellRangeAddress cellAddresses : cellList) {
final int firstRow = cellAddresses.getFirstRow();
if (cellAddresses.isInRange(cell) && rowIndex != firstRow) {
cell.setBlank();
}
}
}
}
@Override
public void afterWorkbookDispose(final WorkbookWriteHandlerContext context) {
//当前表格写完后，统一写入
if (CollUtil.isNotEmpty(cellList)) {
for (CellRangeAddress item : cellList) {
context.getWriteContext().writeSheetHolder().getSheet().addMergedRegion(item);
}
}
}
@SneakyThrows
private List handle(List list, boolean hasTitle) {
List cellList = new ArrayList<>();
if (CollUtil.isEmpty(list)) {
return cellList;
}
Field[] fields = ReflectUtil.getFields(list.get(0).getClass(), field -> !"serialVersionUID".equals(field.getName()));
// 有注解的字段
List mergeFields = new ArrayList<>();
List mergeFieldsIndex = new ArrayList<>();
for (int i = 0; i < fields.length; i++) {
Field field = fields[i];
if (field.isAnnotationPresent(CellMerge.class)) {
CellMerge cm = field.getAnnotation(CellMerge.class);
mergeFields.add(field);
mergeFieldsIndex.add(cm.index() == -1 ? i : cm.index());
if (hasTitle) {
ExcelProperty property = field.getAnnotation(ExcelProperty.class);
rowIndex = Math.max(rowIndex, property.value().length);
}
}
}
Map map = new HashMap<>();
// 生成两两合并单元格
for (int i = 0; i < list.size(); i++) {
for (int j = 0; j < mergeFields.size(); j++) {
Field field = mergeFields.get(j);
Object val = ReflectUtil.invokeGetter(list.get(i), field.getName());
int colNum = mergeFieldsIndex.get(j);
if (!map.containsKey(field)) {
map.put(field, new RepeatCell(val, i));
} else {
RepeatCell repeatCell = map.get(field);
Object cellValue = repeatCell.getValue();
if (cellValue == null || "".equals(cellValue)) {
// 空值跳过不合并
continue;
}
if (!cellValue.equals(val)) {
if ((i - repeatCell.getCurrent() > 1) && isMerge(list, i, field)) {
cellList.add(new CellRangeAddress(repeatCell.getCurrent() + rowIndex, i + rowIndex - 1, colNum, colNum));
}
map.put(field, new RepeatCell(val, i));
} else if (i == list.size() - 1) {
if (i > repeatCell.getCurrent() && isMerge(list, i, field)) {
cellList.add(new CellRangeAddress(repeatCell.getCurrent() + rowIndex, i + rowIndex, colNum, colNum));
}
}
}
}
}
return cellList;
}
private boolean isMerge(List list, int i, Field field) {
boolean isMerge = true;
CellMerge cm = field.getAnnotation(CellMerge.class);
final String[] mergeBy = cm.mergeBy();
if (StrUtil.isAllNotBlank(mergeBy)) {
//比对当前list(i)和list(i - 1)的各个属性值一一比对 如果全为真 则为真
for (String fieldName : mergeBy) {
final Object valCurrent = ReflectUtil.getFieldValue(list.get(i), fieldName);
final Object valPre = ReflectUtil.getFieldValue(list.get(i - 1), fieldName);
if (!Objects.equals(valPre, valCurrent)) {
//依赖字段如有任一不等值,则标记为不可合并
isMerge = false;
}
}
}
return isMerge;
}
@Data
@AllArgsConstructor
static class RepeatCell {
private Object value;
private int current;
}
}