Java Excel动态列 导出

Java可以使用Apache POI库来操作Excel文件，实现动态列导出。下面是一个示例代码：

public void exportExcel(List<Map<String, Object>> dataList, HttpServletResponse response) throws IOException {
    // 创建工作簿
    Workbook workbook = new XSSFWorkbook();
    // 创建工作表
    Sheet sheet = workbook.createSheet("Sheet1");
    // 创建表头
    Row headerRow = sheet.createRow(0);
    List<String> headerList = new ArrayList<>();
    for (Map.Entry<String, Object> entry : dataList.get(0).entrySet()) {
        headerList.add(entry.getKey());
    }
    for (int i = 0; i < headerList.size(); i++) {
        Cell headerCell = headerRow.createCell(i);
        headerCell.setCellValue(headerList.get(i));
    }
    // 填充数据
    int rowIndex = 1;
    for (Map<String, Object> data : dataList) {
        Row row = sheet.createRow(rowIndex++);
        int columnIndex = 0;
        for (Map.Entry<String, Object> entry : data.entrySet()) {
            Cell cell = row.createCell(columnIndex++);
            cell.setCellValue(entry.getValue().toString());
        }
    }
    // 设置响应头信息
    response.setContentType("application/vnd.ms-excel");
    response.setCharacterEncoding("utf-8");
    response.setHeader("Content-disposition", "attachment;filename=data.xlsx");
    // 输出Excel文件
    OutputStream outputStream = response.getOutputStream();
    workbook.write(outputStream);
    outputStream.flush();
    outputStream.close();
}

其中，`dataList`是一个包含多个Map的List，每个Map代表一行数据，Map的key为列名，value为对应的值。这样，我们就可以根据传入的数据动态地生成Excel文件了。