String Month-Year to Local Date

Question

I am trying to parse some date-string into a date value, however, using the below code, I am getting an exception:

My Code

DateTimeFormatter formatter = new DateTimeFormatterBuilder()
                            .parseCaseInsensitive()
                            .append(DateTimeFormatter.ofPattern("MMMM-YYYY"))
                            .toFormatter(Locale.ENGLISH);

LocalDate KFilter = LocalDate.parse("August-2021", formatter);

The error log is

java.time.format.DateTimeParseException: Text 'August-2021' could not be parsed: 
Unable to obtain LocalDate from TemporalAccessor: {WeekBasedYear[WeekFields[SUNDAY,1]]=2021, MonthOfYear=8},
ISO of type java.time.format.Parsed

Can you please help me out on the same ?

Use `y` instead of `Y` and then use `parseDefaulting` for the default value of the day-of-month. There are tens of questions already asked regarding this problem. — Arvind Kumar Avinash, Aug 09 '21 at 15:31
Does this answer your question? [Difference between year-of-era and week-based-year?](https://stackoverflow.com/questions/26431882/difference-between-year-of-era-and-week-based-year) — Elias Holzmann, Aug 09 '21 at 15:40

Ole V.V. · Accepted Answer · 2021-08-09T16:48:00.543

    DateTimeFormatter formatter = new DateTimeFormatterBuilder()
            .parseCaseInsensitive()
            .append(DateTimeFormatter.ofPattern("MMMM-uuuu"))
            .toFormatter(Locale.ENGLISH);

    LocalDate kFilter = YearMonth.parse("August-2021", formatter).atDay(1);

    System.out.println(kFilter);

Output:

2021-08-01

What went wrong in your code?

There are two problems with your code:

Format pattern strings are case sensitive. Upper case YYYY is for week-based year and only useful with a week number. Use either lower case yyyy or uuuu.
Month and year do not define a date, so you cannot readily parse them into a LocalDate. I suggest you parse into a YearMonth and then convert. In the conversion you need to decise on a day of month. An alternative would be specifying a day of month through DateTimeFormatterBuilder.parseDefaulting().

String Month-Year to Local Date

1 Answers1

What went wrong in your code?

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