基于Java POI实现动态列Excel导出的通用方法

LinkedHashMap<String, Integer> allColumn = new LinkedHashMap<>();
// 先添加固定列
for (int i = 0; i < strCloumnAry.length; i++) {
    allColumn.putIfAbsent(strCloumnAry[i], i);
}
// 再添加动态列（避免重复）
int i = strCloumnAry.length;
for (String key : cellList) {
    if (!allColumn.containsKey(key)) {
        allColumn.put(key, i++);
    }
}

if (headerNum == 2) { // 二级表头处理
    for (String key : allColumn.keySet()) {
        String[] parts = key.split("\|\|"); // 按||拆分
        if (parts.length == 2) {
            // 一级表头行
            Cell cell1 = headerRow1.createCell(allColumn.get(key));
            cell1.setCellValue(parts[0]);
            // 二级表头行
            Cell cell2 = headerRow2.createCell(allColumn.get(key));
            cell2.setCellValue(parts[1]);
        }
    }
}

// 写入数据行
int row = headerNum; // 表头行下方开始写数据
for (Map<String, Object> data : datas) {
    Row dataRow = sheet.createRow(row++);
    for (Map.Entry<String, Integer> entry : allColumn.entrySet()) {
        Cell cell = dataRow.createCell(entry.getValue());
        cell.setCellValue(data.get(entry.getKey()) != null ? data.get(entry.getKey()).toString() : "");
    }
}

// 写入合计行
Row totalRow = sheet.createRow(row);
totalRow.createCell(0).setCellValue("合计");
for (Map.Entry<String, Object> entry : totalMap.entrySet()) {
    int colIndex = allColumn.get(entry.getKey());
    Cell cell = totalRow.createCell(colIndex);
    cell.setCellValue(entry.getValue() != null ? entry.getValue().toString() : "");
}
// 合并合计行标题单元格
sheet.addMergedRegion(new CellRangeAddress(row, row, 0, maxSp));

// 创建通用样式
CellStyle cellStyle = workbook.createCellStyle();
cellStyle.setAlignment(HorizontalAlignment.CENTER);
cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
cellStyle.setBorderTop(BorderStyle.THIN);
cellStyle.setBorderBottom(BorderStyle.THIN);
cellStyle.setBorderLeft(BorderStyle.THIN);
cellStyle.setBorderRight(BorderStyle.THIN);

// 表头字体设置
Font headerFont = workbook.createFont();
headerFont.setFontHeightInPoints((short) 10);
cellStyle.setFont(headerFont);

// 假设前端传入动态列名为["price","quantity"]
List<String> cellList = Arrays.asList("price", "quantity");
// 固定列字段名与显示名
String[] strCloumnAry = {"name", "date"};
String[] strAry = {"商品名称", "日期"};

// 构造模拟数据
List<Map<String, Object>> datas = new ArrayList<>();
Map<String, Object> data1 = new HashMap<>();
data1.put("name", "苹果");
data1.put("date", "2023-10-01");
data1.put("price", 5.99);
data1.put("quantity", 100);
datas.add(data1);

// 调用导出方法（二级表头示例）
exportDynamicExcel(response, datas, cellList, "商品销售报表", strAry, strCloumnAry, 2);