Java Period.between 显示奇怪的输出

Question

我正在制作一个仅用于学习目的的应用程序。我试图计算两个日期之间的差异

LocalDate today  = LocalDate.now();
LocalDate localHoudbaarheid = houdbaarheidsDatum;
Period period = Period.between(today, localHoudbaarheid);

计算有效，但输出很奇怪。
代码的输出:

Dagen tot over de datum: P9D

唯一应该显示的是 9没有 P和 D .这是我在代码中调用名称句点以将其打印出来的地方:

"Dagen tot over de datum: " + period;

Answer 1

输出没有什么奇怪的，正是文档 ，即 Period.toString() 的 javadoc说它是:

Outputs this period as a String, such as P6Y3M1D.

The output will be in the ISO-8601 period format. A zero period will be represented as zero days, 'P0D'.

正如文档所说，输出遵循 ISO-8601 standard持续时间，如 Wikipedia 上所述:

Durations define the amount of intervening time in a time interval and are represented by the format P[n]Y[n]M[n]DT[n]H[n]M[n]S ...

• P is the duration designator (for period) placed at the start of the duration representation.

  • Y is the year designator that follows the value for the number of years.
  • M is the month designator that follows the value for the number of months.
  • W is the week designator that follows the value for the number of weeks.
  • D is the day designator that follows the value for the number of days.