POI创建Excel文件

/**
 * 创建Excel,支持.xls格式，当数据小于30000条，该方法完全没问题
 * 最大支持65535条数据，Excel2003最大支持数据条数
 * @param title 表名称
 * @param head  数据标题
 * @param list 数据集合
 * @return Excel
 */
public static HSSFWorkbook createExcel(String title, Map<String, String> head, List list){
    HSSFWorkbook workbook = new HSSFWorkbook();
    //创建工作表
    HSSFSheet sheet = workbook.createSheet(title);
    //添加表头
    HSSFRow row = sheet.createRow(0);
    //设置单元格格式
    HSSFCellStyle cellStyle = workbook.createCellStyle();
    cellStyle.setAlignment(HorizontalAlignment.CENTER);
    //添加表头内容
    List<String> cells = createHeadCell(row, head, cellStyle);

    //遍历数据集
    createDataCell(sheet, list, row, cellStyle, cells);

    return workbook;
}

/**
 * 创建Excel,仅支持.xlsx格式 Excel2007 之后
 * @param title 表名称
 * @param head  数据标题
 * @param list 数据集合
 * @return Excel
 */
public static SXSSFWorkbook createBigExcel(String title, Map<String, String> head, List list){
    SXSSFWorkbook workbook = new SXSSFWorkbook();
    //创建工作表
    SXSSFSheet sheet = workbook.createSheet(title);
    //添加表头
    SXSSFRow row = sheet.createRow(0);
    //设置单元格格式
    CellStyle cellStyle = workbook.createCellStyle();
    cellStyle.setAlignment(HorizontalAlignment.CENTER);
    //添加表头内容
    List<String> cells = createHeadCell(row, head, cellStyle);

    //遍历数据集
    createDataCell(sheet, list, row, cellStyle, cells);

    return workbook;
}

private static void createDataCell(Sheet sheet, List list, Row row, CellStyle cellStyle, List<String> cells){
    Cell cell;
    for (int i = 0; i < list.size(); i++) {
        row = sheet.createRow(i + 1);
        Object t = list.get(i);
        try {
            for (int j = 0; j < cells.size(); j++) {
                Field field = t.getClass().getDeclaredField(cells.get(j));
                Class<?> type = field.getType();
                String fieldName = field.getName();
                String methodName;
                if (boolean.class == type) {
                    methodName = "is" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);
                } else {
                    methodName = "get" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);
                }
                Method method = t.getClass().getMethod(methodName);
                //创建单元格并设置值
                cell = row.createCell(j);
                cell.setCellStyle(cellStyle);
                if (Integer.class == type) {
                    Integer value = (Integer) method.invoke(t);
                    cell.setCellValue(value);
                } else if (String.class == type) {
                    String value = (String) method.invoke(t);
                    cell.setCellValue(value);
                } else if (Long.class == type) {
                    Long value = (Long) method.invoke(t);
                    cell.setCellValue(value);
                } else if (Short.class == type) {
                    Short value = (Short) method.invoke(t);
                    cell.setCellValue(value);
                } else if (Character.class == type) {
                    Character value = (Character) method.invoke(t);
                    cell.setCellValue(value);
                } else if (Double.class == type) {
                    Double value = (Double) method.invoke(t);
                    cell.setCellValue(value);
                } else if (Date.class == type) {
                    Date value = (Date) method.invoke(t);
                    cell.setCellValue(value);
                } else if (Boolean.class == type) {
                    Boolean value = (Boolean) method.invoke(t);
                    cell.setCellValue(value);
                }
            }
        } catch (Exception e) {
            log.error("创建Excel文件发生异常》》》》》》》》", e);
        }
    }
}

private static List<String> createHeadCell(Row row, Map<String, String> head, CellStyle cellStyle){
    Cell headCell;
    int cellNum = 0;
    List<String> cells = new ArrayList<>();
    for (Iterator<String> iterator = head.keySet().iterator(); iterator.hasNext();) {
        String name = iterator.next();
        cells.add(name);
        headCell = row.createCell(cellNum);
        headCell.setCellStyle(cellStyle);
        headCell.setCellValue(head.get(name));
        cellNum ++;
    }
    return cells;
}