I'm familiar with the DateTime Formatter in regards to applying LocalDate to a single variable, but don't know how to handle the following situation: I've two LocalDate variables, for example startOfWeek and endOfWeek. And I need to create String result with following rules:

1. if startOfWeek and endOfWeek have same month and year, the result should be like 3 - 9 Jan 2021 (just an example with format)
2. if startOfWeek and endOfWeek have not same month, the result should be like 31 Oct - 6 Nov 2021
3. if startOfWeek and endOfWeek have not same year, the result should be like 27 Dec 2020 - 2 Jan 2021

I didn't find how to apply DateTime Formatter working with two of more LocalDate variables, so I've made this way:

if ((startOfWeek.getYear() != endOfWeek.getYear())){
                result.append(startOfWeek.getDayOfMonth()   " "   startOfWeek.getMonth()   " "   startOfWeek.getYear()  
                        " - "   endOfWeek.getDayOfMonth()   " "   endOfWeek.getMonth()   " "   startOfWeek.getYear());
                return  result.toString();
            } else if ((startOfWeek.getMonth() != endOfWeek.getMonth())) {
                result.append(startOfWeek.getDayOfMonth()   " "   startOfWeek.getMonth()  
                        " - "   endOfWeek.getDayOfMonth()   " "   endOfWeek.getMonth()   " "   startOfWeek.getYear());
                return  result.toString();
            } else {
                result.append(startOfWeek.getDayOfMonth()  
                        " - "   endOfWeek.getDayOfMonth()   " "   startOfWeek.getMonth()   " "   startOfWeek.getYear());
                return  result.toString();

But it return information about months in default format, for example SEPTEMBER

Full example:

Does anybody now how to fix month data format or how to use DateTime Formatter with two LocalDate variables at one time? Thank you in advance for your help.

CodePudding user response：

You could use a DateTimeFormatter to get a formated month string

DateTimeFormatter month  = DateTimeFormatter.ofPattern("MMM");

In addition to that I would do the task with 3 DateTimeFormatters and the YearMonth and Year classes from java.time API which could make your if else blocks a bit more readable:

import java.time.LocalDate;
import java.time.Year;
import java.time.YearMonth;
import java.time.format.DateTimeFormatter;
import java.util.List;

....


static String formattedRange (LocalDate start, LocalDate end){
    DateTimeFormatter onlyDate      = DateTimeFormatter.ofPattern("d");
    DateTimeFormatter dateAndMonth  = DateTimeFormatter.ofPattern("d MMM");
    DateTimeFormatter dateMonthYear = DateTimeFormatter.ofPattern("d MMM yyyy");

    StringBuilder result = new StringBuilder();
    if (YearMonth.from(start).equals(YearMonth.from(end))){
        result.append(onlyDate.format(start)).append(" - ")
              .append(dateMonthYear.format(end));
    }
    else if (Year.from(start).equals(Year.from(end))){
        result.append(dateAndMonth.format(start)).append(" - ")
              .append(dateMonthYear.format(end));
    }
    else {
        result.append(dateMonthYear.format(start)).append(" - ")
              .append(dateMonthYear.format(end));
    }
    return result.toString();
}

CodePudding user response：

You can use the .getDisplayName(...) method directly on the getMonth() method to get the desired localized month name format. In your case, here is an example code:

startOfWeek.getMonth().getDisplayName(TextStyle.SHORT_STANDALONE,Locale.getDefault())
endOfWeek.getMonth().getDisplayName(TextStyle.SHORT_STANDALONE, Locale.getDefault())

CodePudding user response：

I would just use a Formatter string:

String format;
if (startOfWeek.getYear() != endOfWeek.getYear()) {
    format = "%te %<tb %<tY - %te %<tb %<tY";
} else if (startOfWeek.getMonth() != endOfWeek.getMonth()) {
    format = "%te %<tb - %te %<tb %<tY";
} else {
    format = "%te - %te %<tb %<tY";
}

return String.format(format, startOfWeek, endOfWeek);