I'm trying to parse a string into a timestamp using java.time.format. I am expected it to be in this format "dd/MM/yyyy HH:mm:ss". Here is my code.

val timeString = "Mon Sep 20 15:57:56 BST 2021"
val formatFinal = DateTimeFormatter.ofPattern("dd/MM/yyyy HH:mm:ss")
val startTs = formatFinal.parse(timeString)

However i'm getting this error and I'm not sure why. I'm new to scala/java so may have missed something obvious.

 Text 'Mon Sep 20 15:57:56 BST 2021' could not be parsed at index 0

CodePudding user response：

This works.

import java.time.format.{DateTimeFormatter => DTF}

val timeString = "Mon Sep 20 15:57:56 BST 2021"
val formatFinal = DTF.ofPattern("E LLL dd HH:mm:ss z yyyy")
val startTs = formatFinal.parse(timeString)

//val startTs: java.time.temporal.TemporalAccessor = {InstantSeconds=1632113876},ISO,Pacific/Bougainville resolved to 2021-09-20T15:57:56

I'm not sure that's the result you want, but it parses the timeString.

CodePudding user response：

To parse date from string to LocalDateTime and back to string in different format you need to have 2 formatters, first one to read the date from string and parse it to LocalDateTime and the other one to write LocalDateTime back to string in the format you want.

val timeString = "Mon Sep 20 15:57:56 BST 2021"
val formatSource = DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss z yyyy")
val formatOuput = DateTimeFormatter.ofPattern("dd/MM/yyyy HH:mm:ss")
val startTs = LocalDateTime.parse(timeString, format).format(formatFinal)