在Scala中转换日期格式

Question

I am trying to convert a date format of that looks like this: 2011-09-30 00:00:00.0 to 20110930 in scala. Does anyone have any ideas?

Answer 1

If all you want to do is to change date format from string to string all you may do something similar to:

def toSimpleDate(dateString: String): Option[String] = {
  val parser = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.S")
  val formatter = DateTimeFormatter.ofPattern("yyyyMMdd")

  Try {
    LocalDateTime.parse(dateString, parser)
  }.toOption
    .map(_.format(formatter))
}

toSimpleDate("2011-09-30 00:00:00.0") // Some("20119030")
toSimpleDate("Meh") // None

Answer 2

Use something like this:

import java.text.SimpleDateFormat

val inputFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S")
val outputFormat = new SimpleDateFormat("ddMMyyyy")

val date = "2015-01-31 12:34:00.0"
val formattedDate = outputFormat.format(inputFormat.parse(date))

println(formattedDate) //20150131

Answer 3

You can probably use the Date Functions as mentioned in other answers. However if you are sure about the format to be 2011-09-30 00:00:00.0

A simple Map operation should be fine

val x = List("2011-09-30 00:00:00.0")
val output = x map (x => x.dropRight(11).replace("-",""))
> output: List[String] = List(20110930)

However this solution works If and Only If You can guarantee the input comes in the same format.