public static long timeStrConvertToMillSec(String time, String cycleUnit) {
        long defaultTime = System.currentTimeMillis();
        if (time.isEmpty() || cycleUnit.isEmpty()) {
            return defaultTime;
        }
        String pattern = DEFAULT_PATTERN;
        switch (cycleUnit) {
            case DAY:
                pattern = DAY_PATTERN;
                time = time.substring(0, 8);
                break;
            case HOUR:
            case HOUR_LOW_CASE:
                pattern = HOUR_PATTERN;
                time = time.substring(0, 10);
                break;
            case MINUTE:
                break;
            default:
                LOGGER.error("cycle unit {} is illegal, please check!", cycleUnit);
                break;
        }
        return parseTimeToMillSec(time, pattern);
    }
Convert the time string to mill second.
inlong-agent/agent-common/src/main/java/org/apache/inlong/agent/utils/AgentUtils.java