获得时间,分钟,秒,毫秒,微秒

Question

我有这个代码:

SimpleDateFormat sDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

我知道这段代码会在时间内返回小时,分钟,秒.我怎么能得到毫秒和微秒？

Answer 1

您将不会有微秒,因为Date存储自1970年1月1日以来的毫秒数.对于毫秒,请使用S,如javadoc中所述.

Answer 2

获得微秒的唯一方法是自己解析字符串.注意:Date应该用于存储微秒,但你可以使用一个long.(你也可以使用毫秒或纳秒)

private static final String YEARS_TO_MINUTES = "yyyy-MM-dd HH:mm";
private static final SimpleDateFormat YEARS_TO_MINUTES_SDF = new SimpleDateFormat(YEARS_TO_MINUTES);

public static long parseMicroSeconds(String text) throws ParseException {
    long timeMS;
    synchronized (YEARS_TO_MINUTES_SDF) {
        timeMS = YEARS_TO_MINUTES_SDF.parse(text.substring(0, YEARS_TO_MINUTES.length())).getTime();
    }
    long microSecs = 0;
    if (text.length() > YEARS_TO_MINUTES.length() + 1) {
        double secs = Double.parseDouble(text.substring(YEARS_TO_MINUTES.length() + 1));
        microSecs = (long) (secs * 1e6 + 0.5);
    }
    return timeMS * 1000 + microSecs;
}

public static String formatMicroSeconds(long timeMicroSeconds) {
    String dateTime;
    synchronized (YEARS_TO_MINUTES_SDF) {
        dateTime = YEARS_TO_MINUTES_SDF.format(new Date(timeMicroSeconds / 1000));
    }
    long secs = timeMicroSeconds % 60000000;
    return dateTime + String.format(":%09.6f", secs / 1e6);
}


public static void main(String... args) throws ParseException {
    String dateTime = "2011-01-17 19:27:59.999650";
    long timeUS = parseMicroSeconds(dateTime);
    for (int i = 0; i < 5; i++)
        System.out.println(formatMicroSeconds(timeUS += 175));
}

版画

2011-01-17 19:27:59.999825
2011-01-17 19:28:00.000000
2011-01-17 19:28:00.000175
2011-01-17 19:28:00.000350
2011-01-17 19:28:00.000525

如果您需要纳米计时,您可以做同样的事情.