How to format LocalDate object to MM/dd/yyyy and have format persist

Question

I am reading text and storing the dates as LocalDate variables.

Is there any way for me to preserve the formatting from DateTimeFormatter so that when I call the LocalDate variable it will still be in this format.

EDIT:I want the parsedDate to be stored in the correct format of 25/09/2016 rather than printing as a string

My code:

public static void main(String[] args) 
{
    LocalDate date = LocalDate.now();
    DateTimeFormatter formatters = DateTimeFormatter.ofPattern("d/MM/uuuu");
    String text = date.format(formatters);
    LocalDate parsedDate = LocalDate.parse(text, formatters);

    System.out.println("date: " + date); // date: 2016-09-25
    System.out.println("Text format " + text); // Text format 25/09/2016
    System.out.println("parsedDate: " + parsedDate); // parsedDate: 2016-09-25

    // I want the LocalDate parsedDate to be stored as 25/09/2016
}

A `LocalDate` object does not have a format - it cannot, by itself, remember that it has to be in a specific format such as `MM/dd/yyyy`. — Jesper, Sep 25 '16 at 18:03

score 30 · Answer 1 · answered Sep 25 '16 at 17:51

30

EDIT: Considering your edit, just set parsedDate equal to your formatted text string, like so:

parsedDate = text;

A LocalDate object can only ever be printed in ISO8601 format (yyyy-MM-dd). In order to print the object in some other format, you need to format it and save the LocalDate as a string like you've demonstrated in your own example

DateTimeFormatter formatters = DateTimeFormatter.ofPattern("d/MM/uuuu");
String text = date.format(formatters);

answered Sep 25 '16 at 17:51

Rebecca Close

700
6
11

`cannot convert from String to LocalDate` error when I try that assignment – MOZAKATAK Sep 25 '16 at 17:58
Oh I'm sorry, parsedDate will have to be a string in order to be saved in that format. So you'll have to define parsedDate as a string. – Rebecca Close Sep 25 '16 at 18:00
So there is no other format that a LocalDate variable can take other than yyyy-MM-dd unless you store it instead as a String? Thanks – MOZAKATAK Sep 25 '16 at 18:03
No, see Joe C's answer! Maybe it will explain things better – Rebecca Close Sep 25 '16 at 20:32

score 11 · Answer 2 · answered Sep 25 '16 at 17:46

Just format the date while printing it out:

public static void main(String[] args) {
    LocalDate date = LocalDate.now();
    DateTimeFormatter formatters = DateTimeFormatter.ofPattern("d/MM/uuuu");
    String text = date.format(formatters);
    LocalDate parsedDate = LocalDate.parse(text, formatters);

    System.out.println("date: " + date);
    System.out.println("Text format " + text);
    System.out.println("parsedDate: " + parsedDate.format(formatters));
}

score 3 · Answer 3 · answered Sep 25 '16 at 19:46

Short answer: no.

Long answer: A LocalDate is an object representing a year, month and day, and those are the three fields it will contain. It does not have a format, because different locales will have different formats, and it will make it more difficult to perform the operations that one would want to perform on a LocalDate (such as adding or subtracting days or adding times).

The String representation (produced by toString()) is the international standard on how to print dates. If you want a different format, you should use a DateTimeFormatter of your choosing.

score 1 · Answer 4 · answered Aug 04 '20 at 20:52

No, you cannot have a format persist, because you cannot override toString of LocalDate (constructor of LocalDate is private, it is imposible extends) and there are not a method to change the format in LocalDate persistently.

Maybe, you could create a new class and use an static method to change the format, but you have always to use MyLocalDate.myToString(localDate) instead localDate.toString() when you want other format.

 public class MyLocalDate {
    
    public static String myToString(LocalDate localDate){
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd-MM-yyyy");
        return localDate.format(formatter);
    }   
}

When you invoke you have to use this way

FechaInicioTextField.setText(MyLocalDate.myToString(fechaFacturaInicial));

instead of

FechaInicioTextField.setText(fechaFacturaInicial.toString());

score -1 · Answer 5 · answered Jun 29 '17 at 00:45

This could be possible if you could extend LocalDate and override the toString() method but the LocalDate class is immutable and therefore (secure oop) final. This means that if you wish to use this class the only toString() method you will be able to use is the above (copied from LocalDate sources):

@Override
public String toString() {
    int yearValue = year;
    int monthValue = month;
    int dayValue = day;
    int absYear = Math.abs(yearValue);
    StringBuilder buf = new StringBuilder(10);
    if (absYear < 1000) {
        if (yearValue < 0) {
            buf.append(yearValue - 10000).deleteCharAt(1);
        } else {
            buf.append(yearValue + 10000).deleteCharAt(0);
        }
    } else {
        if (yearValue > 9999) {
            buf.append('+');
        }
        buf.append(yearValue);
    }
    return buf.append(monthValue < 10 ? "-0" : "-")
        .append(monthValue)
        .append(dayValue < 10 ? "-0" : "-")
        .append(dayValue)
        .toString();
}

If you must override this behavior, you could box LocalDate and use your custom toString method but this could cause more problems than it solves!

How to format LocalDate object to MM/dd/yyyy and have format persist

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