如何使用 java.time.ZonedDateTime 生成 UTC 格式的原始 long 值

Question

什么是一种相当有效但最重要的是一种将 UTC 时间戳生成为 long 值（java 原始类型）的简洁明了的方法。

我只需要它精确到最精确的毫秒值。

我更愿意使用 java.time.ZonedDateTime，因为它是一种获取 UTC 时间戳的简洁方法，并且不需要任何我不想使用的外部日期库，例如 Joda 或 Apache。

组成原始long值的19位数字将被分解（格式化）如下并举例：

2015  - 4 digit year with range 1000 - 9223. 
      - no zero padding allowed to ensure length is always 
        a 19 digit long value
      - 1000 is the minimum value of a four digit year 
      - 9223 is the maximum value based on first four digits 
        of Long.MAX_VALUE or 9223372036854775807

01    - 2 digit month with range 01 - 12
      - zero padded to ensure 2 digits always
      - jan is 01 and dec is 12

20    - 2 digit day with range 01 - 31
      - zero padded to ensure 2 digits always

07    - 2 digit hour with range 00 - 23
      - zero padded to ensure 2 digits always
      - uses a 24 hour clock  
      - 00 is 12 AM while 23 is 11 PM

00    - 2 digit minute with range 00 - 59
      - zero padded to ensure 2 digits always

00    - 2 digit second with range 00 - 59
      - zero padded to ensure 2 digits always

999   - 3 digit milliseconds with range 000 - 999
      - zero padded to ensure 3 digits always

99    - only 2 digits left over from primitive long. Ignore these as they 
        will be used internally as specialized counters within my program

我的出发点是使用以下内容：

ZonedDateTime value = ZonedDateTime.now( ZoneOffset.UTC );

Answer 1

ZonedDateTime value = ZonedDateTime.now(ZoneOffset.UTC);
System.out.println(value.get(ChronoField.NANO_OF_SECOND));

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMddHHmmssSSS");
long time = Long.parseLong(formatter.format(value)) * 100;
System.out.println(time);

如何使用 java.time.ZonedDateTime 生成 UTC 格式的原始 long 值

How to use java.time.ZonedDateTime to generate a primitive long value in UTC

java

performance

coding-style

utc

type-conversion