Same day prevous year (previous year, same week and day of week)

Question

I want to retrieve same day previous year.

e.g. today is 2019-03-30 that is year 2019, week 26(week of year), day 7 (day of week).

I need to construct LocalDate which is year 2018, week 26(week of year), day 7 (day of week).

I could not find from java.time package which can built LocalDate like this.

Answer 1

It seems like you want the previous year date with same week of year and day of week as the given date. Below code with give you that result.

LocalDate currentLocalDate = LocalDate.now();
int dayOfWeek = currentLocalDate.getDayOfWeek().getValue();
int weekOfYear = currentLocalDate.get(ChronoField.ALIGNED_WEEK_OF_YEAR);
LocalDate resultLocalDate = currentLocalDate
    .minusYears(1)
    .with(ChronoField.ALIGNED_WEEK_OF_YEAR, weekOfYear)
    .with(ChronoField.DAY_OF_WEEK, dayOfWeek);

Full Example (live copy):

import java.time.*;
import java.time.format.*;
import java.time.temporal.*;

class Example
{
    private static void showDateInfo(LocalDate ld) {
        int weekOfYear = ld.get(ChronoField.ALIGNED_WEEK_OF_YEAR);
        int dayOfWeek = ld.getDayOfWeek().getValue();
        System.out.println(ld.format(DateTimeFormatter.ISO_LOCAL_DATE) + " is week " + weekOfYear + ", day " + dayOfWeek);
    }
    public static void main (String[] args) throws java.lang.Exception
    {
        LocalDate currentLocalDate = LocalDate.of(2019, 6, 30);
        showDateInfo(currentLocalDate);
        int dayOfWeek = currentLocalDate.getDayOfWeek().getValue();
        int weekOfYear = currentLocalDate.get(ChronoField.ALIGNED_WEEK_OF_YEAR);
        LocalDate resultLocalDate = currentLocalDate
            .minusYears(1)
            .with(ChronoField.ALIGNED_WEEK_OF_YEAR, weekOfYear)
            .with(ChronoField.DAY_OF_WEEK, dayOfWeek);
        showDateInfo(resultLocalDate);
    }
}

Output:

2019-06-30 is week 26, day 7
2018-07-01 is week 26, day 7