DateTimeFormatter とかこれもうわかんねぇな
コード
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
public class App {
private static String format(final LocalDate date, final String pattern) {
return date.format(DateTimeFormatter.ofPattern(pattern, Locale.JAPAN));
}
public static void main(final String[] args) {
final LocalDate today = LocalDate.of(2019, 6, 4);
System.out.println(format(today, "M"));
System.out.println(format(today, "MM"));
System.out.println(format(today, "MMM"));
System.out.println(format(today, "MMMM"));
System.out.println(format(today, "MMMMM"));
System.out.println(format(today, "MMMMMM"));
}
}
結果
| パターン | 結果 |
|---|---|
| M | 6 |
| MM | 06 |
| MMM | 6 月 |
| MMMM | 6 月 |
| MMMMM | 6 |
| MMMMMM | IllegalArgumentException: Too many pattern letters: M |
$ java -version
openjdk version "11.0.2" 2019-01-15
OpenJDK Runtime Environment 18.9 (build 11.0.2+9)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.2+9, mixed mode)