Mysql 5.7 compatible Scala/Java DateTimeFormatter expression

mysql-formatter.scala

import java.time._
import java.time.format.{DateTimeFormatter, DateTimeFormatterBuilder}
import java.time.temporal.ChronoField._

// This one doesn't work, because Mysql can return five-digits of precision, if the sixth digit was 0
val badFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSSSSS")


val mysqlFormatter = new DateTimeFormatterBuilder().appendValue(YEAR, 4)
  .appendLiteral('-')
  .appendValue(MONTH_OF_YEAR, 2)
  .appendLiteral('-')
  .appendValue(DAY_OF_MONTH, 2)
  .appendLiteral(' ')
  .appendValue(HOUR_OF_DAY, 2)
  .appendLiteral(':')
  .appendValue(MINUTE_OF_HOUR, 2)
  .optionalStart.appendLiteral(':')
  .appendValue(SECOND_OF_MINUTE, 2)
  .optionalStart.appendFraction(NANO_OF_SECOND, 1, 6, true)
  .toFormatter()

val s = "2022-03-18 13:56:01.857"
val x = LocalDateTime.parse(s, mysqlFormatter)
println(x)
println(f.format(x))