private static DateFormat getCacheDateFormat(String dateFormat) {
        Map<String, SimpleDateFormat> dateFormatMap = DATE_FORMAT_THREAD_LOCAL.get();
        if (dateFormatMap == null) {
            dateFormatMap = new HashMap<String, SimpleDateFormat>();
            DATE_FORMAT_THREAD_LOCAL.set(dateFormatMap);
        } else {
            SimpleDateFormat dateFormatCached = dateFormatMap.get(dateFormat);
            if (dateFormatCached != null) {
                return dateFormatCached;
            }
        }
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat(dateFormat);
        dateFormatMap.put(dateFormat, simpleDateFormat);
        return simpleDateFormat;
    }
Format date

@param date
@param dateFormat
@return
fastexcel-core/src/main/java/cn/idev/excel/util/DateUtils.java