Java 如何将 Date 对象的时间设置为零 (00/00/00)
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How to set time on a Date object to be zero (00/00/00)
提问by Milli
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(0);
This sets it to the deafult value. How do I set it to zero?
这将其设置为默认值。我如何将其设置为零？
回答by matt b
You should probably be aware of what setTimeInMillis()expects:
您可能应该知道setTimeInMillis()期望的是什么：
public void setTimeInMillis(long millis)Sets this Calendar's current time from the given long value.
Parameters:
millis- the new time in UTC milliseconds from the epoch.
public void setTimeInMillis(long millis)根据给定的 long 值设置此日历的当前时间。
参数：
millis- 从纪元开始的以 UTC 毫秒为单位的新时间。
The epoch is defined as:
纪元定义为：
An instant in time can be represented by a millisecond value that is an offset from the Epoch, January 1, 1970 00:00:00.000 GMT (Gregorian).
时间瞬间可以用毫秒值表示，该值是与 Epoch, 1970 年 1 月 1 日 00:00:00.000 GMT（格里高利）的偏移量。
回答by matt b
You can zero-out what value you want using the set method. For example:
您可以使用 set 方法将所需的值归零。例如：
calendar.set(Calendar.HOUR, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);
回答by McDowell
(00/00/00)is not a valid date; the API will not produce this value.
(00/00/00)不是有效日期；API 不会产生这个值。
