How to get list of dates from some date? [duplicat

问题:

This question already has an answer here:

• how to get a list of dates between two dates in java 21 answers

I have two variables:

• startDate - for example 29/04/2018
• howManyDays - for example 30

I want to get list of 30 days from date 29/04/2018. Can you tell me how can I do it? I found only days beetwen two dates.

int days = Days.daysBetween(startDate, endDate).getDays();
List<LocalDate> dates = new ArrayList<LocalDate>(days);  // Set initial capacity to `days`.
for (int i=0; i < days; i++) {
    LocalDate d = startDate.withFieldAdded(DurationFieldType.days(), i);
    dates.add(d);
}

I don’t know how to change the code.

回答1:

You can use this sample code to get 30 dates, starting from a specific date.

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;

public class Days {

    public static void main(String[] args) {
        String startDate = "29/04/2018";
        int howManyDays = 30;

        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy");
        LocalDate localDate = LocalDate.parse(startDate, formatter);
        List<LocalDate> dates = new ArrayList<>();
        for (int i = 0; i < howManyDays; i++) {
            dates.add(localDate.plusDays(i));
        }

        //For check
        dates.forEach(System.out::println);
    }
}

Run with howManyDays=5 gives:

2018-04-29
2018-04-30
2018-05-01
2018-05-02
2018-05-03

回答2:

public static List<LocalDate> getLocalDates(String startdate, int days) {
        List<LocalDate> localDates = new ArrayList<>();
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy");
        LocalDate localDate = LocalDate.parse(startdate, formatter);
        for (int i = 1; i <= days; i++) {
            localDates.add(localDate.plusDays(i));

        }
        return localDates;

    }

plusDays should do the trick

回答3:

The other answers are fine. And it will probably take a while still until Java 9 is running on your Android phone, but for anyone else reading along I should like to provide the Java 9 (and later) code snippet:

    LocalDate startDate = LocalDate.of(2018, Month.APRIL, 29);
    int howManyDays = 30;
    List<LocalDate> dates = startDate.datesUntil(startDate.plusDays(howManyDays))
            .collect(Collectors.toList());
    System.out.println(dates);

Output is:

[2018-04-29, 2018-04-30, 2018-05-01, 2018-05-02, 2018-05-03, 2018-05-04, 2018-05-05, 2018-05-06, 2018-05-07, 2018-05-08, 2018-05-09, 2018-05-10, 2018-05-11, 2018-05-12, 2018-05-13, 2018-05-14, 2018-05-15, 2018-05-16, 2018-05-17, 2018-05-18, 2018-05-19, 2018-05-20, 2018-05-21, 2018-05-22, 2018-05-23, 2018-05-24, 2018-05-25, 2018-05-26, 2018-05-27, 2018-05-28]

As I already said in a comment, prefer java.time over Joda-Time (that the snippet you had found for your question was using). java.time is the modern Java date and time API. The Joda-Time home page says:

Note that Joda-Time is considered to be a largely “finished” project. No major enhancements are planned. If using Java SE 8, please migrate to java.time (JSR-310).

If you did want to use the snippet from your question, all you would have to do was delete the first line and change days to howManyDays in the second and third lines.

Links

• Oracle tutorial: Date Time explaining how to use java.time.
• Joda-Time home page