18. Customizing localized date-time formats

Starting with JDK 8, we have a comprehensive date-time API containing classes such as LocalDate, LocalTime, LocalDateTime, ZonedDateTime, OffsetDateTime, and OffsetTime.

We can easily format the date-time output returned by these classes via DateTimeFormatter.ofPattern(). For instance, here, we format a LocalDateTime via the y-MM-dd HH:mm:ss pattern:

// 2023-01-07 15:31:22
String ldt = LocalDateTime.now()
  .format(DateTimeFormatter.ofPattern("y-MM-dd HH:mm:ss"));

More examples are available in the bundled code.

How about customizing our format based on a given locale – for instance, Germany?

Locale.setDefault(Locale.GERMANY);

We accomplish this via ofLocalizedDate(),ofLocalizedTime(), and ofLocalizedDateTime(), as in the following examples:

// 7. Januar 2023
String ld = LocalDate.now().format(
  DateTimeFormatter.ofLocalizedDate(FormatStyle.LONG));
// 15:49
String lt = LocalTime.now().format...