What type of date format is it?

"2018-09-06T10:12:21-0300"

And how can I format it to something like that "06 Sep" ???

CodePudding user response：

What type of date format is it?

This format is one of the ISO 8601 standard, but obviously not for the java.time.format.DateTimeFormatter which considers it a custom format consisting of ISO-standard date and time of day plus an offset from UTC without a separator (colon) between hours and minutes.

And how can I format it to something like that "06 Sep" ???

You need to define two DateTimeFormatters, one for parsing the non-standard input and the other one for outputting day of month and abbreviated month name only. Here's an example:

fun main(args: Array<String>) {
    // some non-ISO formatted String
    val inputDateTime = "2018-09-06T10:12:21-0300"
    // build up a DateTimeFormatter that can parse such a String
    val inputParser = DateTimeFormatterBuilder()
                        // date part uuuu-MM-dd
                        .append(DateTimeFormatter.ISO_LOCAL_DATE)
                        .appendLiteral('T') // the T separating date from time
                        // the time of day part
                        .append(DateTimeFormatter.ISO_LOCAL_TIME)
                        // the offset part without a separator between hours and minutes
                        .appendPattern("X")
                        // (just for completeness) a locale
                        .toFormatter(Locale.ENGLISH)
    // parse the String to an OffsetDateTime
    val offsetDateTime = OffsetDateTime.parse(inputDateTime, inputParser)
    // define another formatter for output, make it only use day of month and abbreviated month in English
    val outputFormatter = DateTimeFormatter.ofPattern("dd MMM", Locale.ENGLISH)
    // print the results
    println("$offsetDateTime ---> ${offsetDateTime.format(outputFormatter)}")
}

Example output:

2018-09-06T10:12:21-03:00 ---> 06 Sep

CodePudding user response：

This format respects the ISO 8601 standard for representing a date/time with timezone information.

There is enough information to parse this string into an OffsetDateTime, but apparently Java's formatter is a bit strict with respect to the missing separator between hours and minutes in the offset representation (which is technically allowed by the standard). This means a plain OffsetDateTime.parse(text) will throw an exception.

Therefore, you'll to define a custom DateTimeFormatter as explained by @deHaar.