Parse a String with week and year into a LocalDate

Question

The kind of String I want to parse : "36/2017", with 36 the week of the year, 2017 the year.

My code :

DateTimeFormatter formatter = new DateTimeFormatterBuilder()
                    .appendPattern("w/uuuu")
                    .parseDefaulting(ChronoField.DAY_OF_WEEK, 1)
                    .toFormatter();
LocalDate date = LocalDate.parse("36/2017", formatter);

I added a default day.

I have this message :

java.time.format.DateTimeParseException: Text '36/2017' could not be parsed: Unable to obtain LocalDate from TemporalAccessor: {WeekOfWeekBasedYear[WeekFields[MONDAY,4]]=36, Year=2017, DayOfWeek=1},ISO of type java.time.format.Parsed

Any idea ? Thank you !

Please provide the stacktrace if possible (you should do this with any exception you're asking about). — Thomas, Aug 29 '19 at 15:08
Tip: Teach the publisher of your input data about the standard [ISO 8601 week date](https://en.wikipedia.org/wiki/ISO_week_date) formats: `2017-W36` — Basil Bourque, Aug 29 '19 at 17:48
Tip: [`YearWeek`](https://www.threeten.org/threeten-extra/apidocs/org.threeten.extra/org/threeten/extra/YearWeek.html) class in the *[ThreeTen-Extra*](https://www.threeten.org/threeten-extra/) project. — Basil Bourque, Aug 29 '19 at 17:51

score 5 · Answer 1 · edited Aug 29 '19 at 15:15

From the docs: https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html

You should use uppercase Y's if you are using weeks.

public static void main(String[] args) {
    DateTimeFormatter formatter = new DateTimeFormatterBuilder()
            .appendPattern("w/YYYY")
            .parseDefaulting(ChronoField.DAY_OF_WEEK, 1)
            .toFormatter();
    LocalDate date = LocalDate.parse("36/2017", formatter);
}

score 4 · Answer 2 · edited Aug 29 '19 at 15:14

4

The pattern is wrong. You must set the following string

"w/YYYY"

DateTimeFormatter formatter = new 
DateTimeFormatterBuilder()
                .appendPattern("w/YYYY")
                .parseDefaulting(ChronoField.DAY_OF_WEEK, 1)
                .toFormatter();
LocalDate date = LocalDate.parse("36/2017", formatter);

edited Aug 29 '19 at 15:14

Youcef LAIDANI

55,661
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answered Aug 29 '19 at 15:11

ynsanity

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Parse a String with week and year into a LocalDate

2 Answers2