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Pez Cuckow
Pez Cuckow

Reputation: 14412

How to get start and end date of a year?

I have to use the Java Date class for this problem (it interfaces with something out of my control).

How do I get the start and end date of a year and then iterate through each date?

Upvotes: 46

Views: 150997

Answers (17)

Stefan Hendriks
Stefan Hendriks

Reputation: 4801

java.time.Year

There is a Year class in java.time.

Examples:

final Year thisYear = Year.of(2024);
System.out.println(thisYear.atDay(1));
System.out.println(thisYear.atDay(thisYear.length()));

Or:

final Year thisYear = Year.of(2024);
System.out.println(thisYear.atMonth(Month.JANUARY).atDay(1));
System.out.println(thisYear.atMonth(Month.DECEMBER).atDay(31));

Or:

final Year thisYear = Year.of(2024);
System.out.println(thisYear.atMonth(Month.JANUARY).atDay(1));
System.out.println(thisYear.atMonth(Month.DECEMBER).atEndOfMonth());

Outputs:

2024-01-01
2024-12-31

To iterate through each date, use LocalDate#datesUntil to create a stream of LocalDate objects.

Year.of(2024).atDay(1)
.datesUntil(
    Year.of(2024).plusYears(1).atDay(1)
)
.forEach( System.out::println ) ;

See that code run at Ideone.com.

2024-01-01
2024-01-02
…
2024-12-30
2024-12-31

Upvotes: 3

PKS
PKS

Reputation: 763

This can be done using TemporalAdjusters methods. The following snippet returns the first date and last date of the current year. However, custom input can also work

 LocalDate localDate = LocalDate.now(ZoneId.systemDefault());
    String firstDayOfYear = localDate.with(TemporalAdjusters.firstDayOfYear()).toString();
    String lastDayOfYear = localDate.with(TemporalAdjusters.lastDayOfYear()).toString();

Upvotes: 1

Avinash Shukla
Avinash Shukla

Reputation: 7

java.time.YearMonth

How to Get First Date and Last Date For Specific Year and Month.

Here is code using YearMonth Class.

YearMonth is a final class in java.time package, introduced in Java 8.

public static void main(String[] args) {

    int year = 2021;  // you can pass any value of year Like 2020,2021...
    int month = 6;   // you can pass any value of month Like 1,2,3...
    YearMonth yearMonth = YearMonth.of( year, month );  
    LocalDate firstOfMonth = yearMonth.atDay( 1 );
    LocalDate lastOfMonth = yearMonth.atEndOfMonth();

    System.out.println(firstOfMonth);
    System.out.println(lastOfMonth);
}

See this code run live at IdeOne.com.

2021-06-01

2021-06-30

Upvotes: -2

Gulzar Bhat
Gulzar Bhat

Reputation: 1355

val instance = Calendar.getInstance()
                instance.add(Calendar.YEAR,-1)

 val prevYear = SimpleDateFormat("yyyy").format(DateTime(instance.timeInMillis).toDate())

val firstDayPreviousYear = DateTime(prevYear.toInt(), 1, 1, 0, 0, 0, 0)

val lastDayPreviousYear = DateTime(prevYear.toInt(), 12, 31, 0, 0, 0, 0)

Upvotes: 0

Rajiv Singh
Rajiv Singh

Reputation: 1078

First and Last day of Year

import java.util.Calendar
import java.text.SimpleDateFormat

val parsedDateInt = new SimpleDateFormat("yyyy-MM-dd")

val cal2 = Calendar.getInstance()
cal2.add(Calendar.MONTH, -(cal2.get(Calendar.MONTH)))
cal2.set(Calendar.DATE, 1)
val firstDayOfYear = parsedDateInt.format(cal2.getTime)


cal2.add(Calendar.MONTH, (11-(cal2.get(Calendar.MONTH))))
cal2.set(Calendar.DATE, cal2.getActualMaximum(Calendar.DAY_OF_MONTH))
val lastDayOfYear = parsedDateInt.format(cal2.getTime)

Upvotes: 0

balaji
balaji

Reputation: 1

Calendar cal = Calendar.getInstance();//getting the instance of the Calendar using the factory method
we have a get() method to get the specified field of the calendar i.e year

int year=cal.get(Calendar.YEAR);//for example we get 2013 here 

cal.set(year, 0, 1); setting the date using the set method that all parameters like year ,month and day
Here we have given the month as 0 i.e Jan as the month start 0 - 11 and day as 1 as the days starts from 1 to30.

Date firstdate=cal.getTime();//here we will get the first day of the year

cal.set(year,11,31);//same way as the above we set the end date of the year

Date lastdate=cal.getTime();//here we will get the last day of the year

System.out.print("the firstdate and lastdate here\n");

Upvotes: -1

Ascarbek Zadauly
Ascarbek Zadauly

Reputation: 59

If you are looking for a one-line-expression, I usually use this:

new SimpleDateFormat("yyyy-MM-dd").parse(String.valueOf(new java.util.Date().getYear())+"-01-01")

Upvotes: 5

Basil Bourque
Basil Bourque

Reputation: 338516

Update: The Joda-Time library is now in maintenance mode with its team advising migration to the java.time classes. See the correct java.time Answer by Przemek.

Time Zone

The other Answers ignore the crucial issue of time zone.

Joda-Time

Avoid doing date-time work with the notoriously troublesome java.util.Date class. Instead use either Joda-Time or java.time. Convert to j.u.Date objects as needed for interoperability. 

DateTimeZone zone = DateTimeZone.forID( "America/Montreal" ) ;
int year = 2015 ;
DateTime firstOfYear = new DateTime( year , DateTimeConstants.JANUARY , 1 , 0 , 0 , zone ) ;
DateTime firstOfNextYear = firstOfYear.plusYears( 1 ) ;
DateTime firstMomentOfLastDayOfYear = firstOfNextYear.minusDays( 1 ) ;

Convert To java.util.Date

Convert to j.u.Date as needed.

java.util.Date d = firstOfYear.toDate() ;

Upvotes: 1

Unni Kris
Unni Kris

Reputation: 3095

An improvement over Srini's answer.
Determine the last date of the year using Calendar.getActualMaximum.

Calendar cal = Calendar.getInstance();

calDate.set(Calendar.DAY_OF_YEAR, 1);
Date yearStartDate = calDate.getTime();

calDate.set(Calendar.DAY_OF_YEAR, calDate.getActualMaximum(Calendar.DAY_OF_YEAR));
Date yearEndDate = calDate.getTime();

Upvotes: 4

Przemek Piotrowski
Przemek Piotrowski

Reputation: 7456

java.time

Using java.time library built into Java 8 and later. Specifically the LocalDate and TemporalAdjusters classes.

import java.time.LocalDate
import static java.time.temporal.TemporalAdjusters.firstDayOfYear
import static java.time.temporal.TemporalAdjusters.lastDayOfYear

LocalDate now = LocalDate.now(); // 2015-11-23
LocalDate firstDay = now.with(firstDayOfYear()); // 2015-01-01
LocalDate lastDay = now.with(lastDayOfYear()); // 2015-12-31

If you need to add time information, you may use any available LocalDate to LocalDateTime conversion like

lastDay.atStartOfDay(); // 2015-12-31T00:00

Upvotes: 127

aleroot
aleroot

Reputation: 72636

Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, 2014);
cal.set(Calendar.DAY_OF_YEAR, 1);    
Date start = cal.getTime();

//set date to last day of 2014
cal.set(Calendar.YEAR, 2014);
cal.set(Calendar.MONTH, 11); // 11 = december
cal.set(Calendar.DAY_OF_MONTH, 31); // new years eve

Date end = cal.getTime();

//Iterate through the two dates 
GregorianCalendar gcal = new GregorianCalendar();
gcal.setTime(start);
while (gcal.getTime().before(end)) {
    gcal.add(Calendar.DAY_OF_YEAR, 1);
    //Do Something ...
}

Upvotes: 49

Grobim
Grobim

Reputation: 1

GregorianCalendar gcal = new GregorianCalendar();
gcal.setTime(start);
while (gcal.getTime().before(end)) {
    gcal.add(Calendar.DAY_OF_YEAR, 1);
    //Do Something ...
}

The GregorianCalendar creation here is pointless. In fact, going through Calendar.java source code shows that Calendar.getInstance() already gives a GregorianCalendar instance.

Regards, Nicolas

Upvotes: -1

tom
tom

Reputation: 2745

You can use the apache commons-lang project which has a DateUtils class.

They provide an iterator which you can give the Date object.

But I highly suggest using the Calendar class as suggested by the other answers.

Upvotes: 0

srini.venigalla
srini.venigalla

Reputation: 5145

 Calendar cal = new GregorianCalendar();
     cal.set(Calendar.DAY_OF_YEAR, 1);
     System.out.println(cal.getTime().toString());
     cal.set(Calendar.DAY_OF_YEAR, 366); // for leap years
     System.out.println(cal.getTime().toString());

Upvotes: 5

JProgrammer
JProgrammer

Reputation: 1135

I assume that you have Date class instance and you need to find first date and last date of the current year in terms of Date class instance. You can use the Calendar class for this. Construct Calendar instance using provided date class instance. Set the MONTH and DAY_OF_MONTH field to 0 and 1 respectively, then use getTime() method which will return Date class instance representing first day of year. You can use same technique to find end of year.

    Date date = new Date();
    System.out.println("date: "+date);
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);

    System.out.println("cal:"+cal.getTime());

    cal.set(Calendar.MONTH, 0);
    cal.set(Calendar.DAY_OF_MONTH, 1);

    System.out.println("cal new: "+cal.getTime());

Upvotes: 2

VirtualTroll
VirtualTroll

Reputation: 3091

    // suppose that I have the following variable as input
    int year=2011;
    Calendar calendarStart=Calendar.getInstance();
    calendarStart.set(Calendar.YEAR,year);
    calendarStart.set(Calendar.MONTH,0);
    calendarStart.set(Calendar.DAY_OF_MONTH,1);
    // returning the first date
    Date startDate=calendarStart.getTime();

    Calendar calendarEnd=Calendar.getInstance();
    calendarEnd.set(Calendar.YEAR,year);
    calendarEnd.set(Calendar.MONTH,11);
    calendarEnd.set(Calendar.DAY_OF_MONTH,31);

    // returning the last date
    Date endDate=calendarEnd.getTime();

To iterate, you should use the calendar object and increment the day_of_month variable

Hope that it can help

Upvotes: 7

Alfabravo
Alfabravo

Reputation: 7569

You can use Jodatime as shown in this thread Java Joda Time - Implement a Date range iterator

Also, you can use gregorian calendar and move one day at a time, as shown here. I need a cycle which iterates through dates interval

PS. Piece of advice: search it first.

Upvotes: 0

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