Custom Date Format with Optional
Description
When defining custom date time format
we can use symbols [ and ]
to mark an optional section.
A pattern enclosed within an optional section is output only if information is available for all its elements.
Example
The following code shows how to use an optional format.
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.Month;
import java.time.format.DateTimeFormatter;
/* w w w. j a v a2 s . c om*/
public class Main {
public static void main(String[] args) {
String pattern = "MM/dd/yyyy[ 'at' HH:mm:ss]";
DateTimeFormatter fmt = DateTimeFormatter.ofPattern(pattern);
LocalDate ld = LocalDate.of(2014, Month.JUNE, 30);
LocalTime lt = LocalTime.of(17, 30, 12);
LocalDateTime ldt = LocalDateTime.of(ld, lt);
String str1 = fmt.format(ld);
System.out.println(str1);
String str2 = fmt.format(ldt);
System.out.println(str2);
}
}
The code above generates the following result.
