Take 3 Integers, create a date - java

I am trying to take 3 separate integer inputs (year,month,day) and taking these 3 entries and forming an object of date from them so I can use it to compare other dates.
This is what I have so far, at a loss at where to go from here:
public void compareDates() {
String dayString = txtOrderDateDay.getText();
String monthString = txtOrderDateMonth.getText();
String yearString = txtOrderDateYear.getText();
int day = Integer.parseInt(dayString);
int month = Integer.parseInt(monthString);
int year = Integer.parseInt(yearString);
}
Many thanks for any help you have to offer.

Try this, noticing that months start in zero so we need to subtract one to correctly specify a month:
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.YEAR, year);
calendar.set(Calendar.MONTH, month-1);
calendar.set(Calendar.DATE, day);
Date date = calendar.getTime();
Or this:
Calendar calendar = Calendar.getInstance();
calendar.set(year, month-1, day);
Date date = calendar.getTime();
Or this:
Date date = new GregorianCalendar(year, month-1, day).getTime();
The first method gives you more control, as it allows you to set other fields in the date, for instance: DAY_OF_WEEK, DAY_OF_WEEK_IN_MONTH, DAY_OF_YEAR, WEEK_OF_MONTH, WEEK_OF_YEAR, MILLISECOND, MINUTE, HOUR, HOUR_OF_DAY etc.
Finally, for correctly formatting the date as indicated in the comments, do this:
DateFormat df = new SimpleDateFormat("yyyy/MM/dd");
String strDate = df.format(date);

Use GregorianCalendar
new GregorianCalendar(int year, int month, int dayOfMonth)

Please refer to this library, in other to facilitate your life in such task - http://joda-time.sourceforge.net/
Then you are gonna write code like this:
LocalDate ld = new LocalDate(int year, int monthOfYear, int dayOfMonth) ;
This class offers a bunch of useful methods for comparison and operations like adding minutes... take a look at its documentation here
A bit more about joda-time:
Joda-Time provides a quality replacement for the Java date and time classes. The design allows for multiple calendar systems, while still providing a simple API. The 'default' calendar is the ISO8601 standard which is used by XML. The Gregorian, Julian, Buddhist, Coptic, Ethiopic and Islamic systems are also included, and we welcome further additions. Supporting classes include time zone, duration, format and parsing.

Related

How to compare date in firestore [duplicate]

I'm working with a date in this format: yyyy-mm-dd.
How can I increment this date by one day?
Something like this should do the trick:
String dt = "2008-01-01"; // Start date
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Calendar c = Calendar.getInstance();
c.setTime(sdf.parse(dt));
c.add(Calendar.DATE, 1); // number of days to add
dt = sdf.format(c.getTime()); // dt is now the new date
UPDATE (May 2021): This is a really outdated answer for old, old Java. For Java 8 and above, see https://stackoverflow.com/a/20906602/314283
Java does appear to be well behind the eight-ball compared to C#. This utility method shows the way to do in Java SE 6 using the Calendar.add method (presumably the only easy way).
public class DateUtil
{
public static Date addDays(Date date, int days)
{
Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.add(Calendar.DATE, days); //minus number would decrement the days
return cal.getTime();
}
}
To add one day, per the question asked, call it as follows:
String sourceDate = "2012-02-29";
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
Date myDate = format.parse(sourceDate);
myDate = DateUtil.addDays(myDate, 1);
java.time
On Java 8 and later, the java.time package makes this pretty much automatic. (Tutorial)
Assuming String input and output:
import java.time.LocalDate;
public class DateIncrementer {
static public String addOneDay(String date) {
return LocalDate.parse(date).plusDays(1).toString();
}
}
I prefer to use DateUtils from Apache. Check this http://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/time/DateUtils.html. It is handy especially when you have to use it multiple places in your project and would not want to write your one liner method for this.
The API says:
addDays(Date date, int amount) : Adds a number of days to a date returning a new object.
Note that it returns a new Date object and does not make changes to the previous one itself.
SimpleDateFormat dateFormat = new SimpleDateFormat( "yyyy-MM-dd" );
Calendar cal = Calendar.getInstance();
cal.setTime( dateFormat.parse( inputString ) );
cal.add( Calendar.DATE, 1 );
Construct a Calendar object and call add(Calendar.DATE, 1);
Java 8 added a new API for working with dates and times.
With Java 8 you can use the following lines of code:
// parse date from yyyy-mm-dd pattern
LocalDate januaryFirst = LocalDate.parse("2014-01-01");
// add one day
LocalDate januarySecond = januaryFirst.plusDays(1);
Take a look at Joda-Time (https://www.joda.org/joda-time/).
DateTimeFormatter parser = ISODateTimeFormat.date();
DateTime date = parser.parseDateTime(dateString);
String nextDay = parser.print(date.plusDays(1));
Please note that this line adds 24 hours:
d1.getTime() + 1 * 24 * 60 * 60 * 1000
but this line adds one day
cal.add( Calendar.DATE, 1 );
On days with a daylight savings time change (25 or 23 hours) you will get different results!
you can use Simple java.util lib
Calendar cal = Calendar.getInstance();
cal.setTime(yourDate);
cal.add(Calendar.DATE, 1);
yourDate = cal.getTime();
Date today = new Date();
SimpleDateFormat formattedDate = new SimpleDateFormat("yyyyMMdd");
Calendar c = Calendar.getInstance();
c.add(Calendar.DATE, 1); // number of days to add
String tomorrow = (String)(formattedDate.format(c.getTime()));
System.out.println("Tomorrows date is " + tomorrow);
This will give tomorrow's date. c.add(...) parameters could be changed from 1 to another number for appropriate increment.
If you are using Java 8, then do it like this.
LocalDate sourceDate = LocalDate.of(2017, Month.MAY, 27); // Source Date
LocalDate destDate = sourceDate.plusDays(1); // Adding a day to source date.
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd"); // Setting date format
String destDate = destDate.format(formatter)); // End date
If you want to use SimpleDateFormat, then do it like this.
String sourceDate = "2017-05-27"; // Start date
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Calendar calendar = Calendar.getInstance();
calendar.setTime(sdf.parse(sourceDate)); // parsed date and setting to calendar
calendar.add(Calendar.DATE, 1); // number of days to add
String destDate = sdf.format(calendar.getTime()); // End date
Since Java 1.5 TimeUnit.DAYS.toMillis(1) looks more clean to me.
SimpleDateFormat dateFormat = new SimpleDateFormat( "yyyy-MM-dd" );
Date day = dateFormat.parse(string);
// add the day
Date dayAfter = new Date(day.getTime() + TimeUnit.DAYS.toMillis(1));
long timeadj = 24*60*60*1000;
Date newDate = new Date (oldDate.getTime ()+timeadj);
This takes the number of milliseconds since epoch from oldDate and adds 1 day worth of milliseconds then uses the Date() public constructor to create a date using the new value. This method allows you to add 1 day, or any number of hours/minutes, not only whole days.
In Java 8 simple way to do is:
Date.from(Instant.now().plusSeconds(SECONDS_PER_DAY))
It's very simple, trying to explain in a simple word.
get the today's date as below
Calendar calendar = Calendar.getInstance();
System.out.println(calendar.getTime());// print today's date
calendar.add(Calendar.DATE, 1);
Now set one day ahead with this date by calendar.add method which takes (constant, value). Here constant could be DATE, hours, min, sec etc. and value is the value of constant. Like for one day, ahead constant is Calendar.DATE and its value are 1 because we want one day ahead value.
System.out.println(calendar.getTime());// print modified date which is tomorrow's date
Thanks
startCalendar.add(Calendar.DATE, 1); //Add 1 Day to the current Calender
In java 8 you can use java.time.LocalDate
LocalDate parsedDate = LocalDate.parse("2015-10-30"); //Parse date from String
LocalDate addedDate = parsedDate.plusDays(1); //Add one to the day field
You can convert in into java.util.Date object as follows.
Date date = Date.from(addedDate.atStartOfDay(ZoneId.systemDefault()).toInstant());
You can formate LocalDate into a String as follows.
String str = addedDate.format(DateTimeFormatter.ofPattern("yyyy-MM-dd"));
With Java SE 8 or higher you should use the new Date/Time API
int days = 7;
LocalDate dateRedeemed = LocalDate.now();
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/YYYY");
String newDate = dateRedeemed.plusDays(days).format(formatter);
System.out.println(newDate);
If you need to convert from java.util.Date to java.time.LocalDate, you may use this method.
public LocalDate asLocalDate(Date date) {
Instant instant = date.toInstant();
ZonedDateTime zdt = instant.atZone(ZoneId.systemDefault());
return zdt.toLocalDate();
}
With a version prior to Java SE 8 you may use Joda-Time
Joda-Time provides a quality replacement for the Java date and time
classes and is the de facto standard date and time library for Java
prior to Java SE 8
int days = 7;
DateTime dateRedeemed = DateTime.now();
DateTimeFormatter formatter = DateTimeFormat.forPattern("dd/MM/uuuu");
String newDate = dateRedeemed.plusDays(days).toString(formatter);
System.out.println(newDate);
Apache Commons already has this DateUtils.addDays(Date date, int amount) http://commons.apache.org/proper/commons-lang/apidocs/org/apache/commons/lang3/time/DateUtils.html#addDays%28java.util.Date,%20int%29 which you use or you could go with the JodaTime to make it more cleaner.
Just pass date in String and number of next days
private String getNextDate(String givenDate,int noOfDays) {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
Calendar cal = Calendar.getInstance();
String nextDaysDate = null;
try {
cal.setTime(dateFormat.parse(givenDate));
cal.add(Calendar.DATE, noOfDays);
nextDaysDate = dateFormat.format(cal.getTime());
} catch (ParseException ex) {
Logger.getLogger(GR_TravelRepublic.class.getName()).log(Level.SEVERE, null, ex);
}finally{
dateFormat = null;
cal = null;
}
return nextDaysDate;
}
If you want to add a single unit of time and you expect that other fields to be incremented as well, you can safely use add method. See example below:
SimpleDateFormat simpleDateFormat1 = new SimpleDateFormat("yyyy-MM-dd");
Calendar cal = Calendar.getInstance();
cal.set(1970,Calendar.DECEMBER,31);
System.out.println(simpleDateFormat1.format(cal.getTime()));
cal.add(Calendar.DATE, 1);
System.out.println(simpleDateFormat1.format(cal.getTime()));
cal.add(Calendar.DATE, -1);
System.out.println(simpleDateFormat1.format(cal.getTime()));
Will Print:
1970-12-31
1971-01-01
1970-12-31
Use the DateFormat API to convert the String into a Date object, then use the Calendar API to add one day. Let me know if you want specific code examples, and I can update my answer.
Try this method:
public static Date addDay(int day) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(new Date());
calendar.add(Calendar.DATE, day);
return calendar.getTime();
}
It's simple actually.
One day contains 86400000 milliSeconds.
So first you get the current time in millis from The System by usingSystem.currentTimeMillis() then
add the 84000000 milliSeconds and use the Date Class to generate A date format for the milliseconds.
Example
String Today = new Date(System.currentTimeMillis()).toString();
String Today will be 2019-05-9
String Tommorow = new Date(System.currentTimeMillis() + 86400000).toString();
String Tommorow will be 2019-05-10
String DayAfterTommorow = new Date(System.currentTimeMillis() + (2 * 86400000)).toString();
String DayAfterTommorow will be 2019-05-11
You can use this package from "org.apache.commons.lang3.time":
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date myNewDate = DateUtils.addDays(myDate, 4);
Date yesterday = DateUtils.addDays(myDate, -1);
String formatedDate = sdf.format(myNewDate);
If you are using Java 8, java.time.LocalDate and java.time.format.DateTimeFormatter can make this work quite simple.
public String nextDate(String date){
LocalDate parsedDate = LocalDate.parse(date);
LocalDate addedDate = parsedDate.plusDays(1);
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-mm-dd");
return addedDate.format(formatter);
}
The highest voted answer uses legacy java.util date-time API which was the correct thing to do in 2009 when the question was asked. In March 2014, java.time API supplanted the error-prone legacy date-time API. Since then, it is strongly recommended to use this modern date-time API.
I'm working with a date in this format: yyyy-mm-dd
You have used the wrong letter for the month, irrespective of whether you are using the legacy parsing/formatting API or the modern one. The letter m is used for minute-of-hour and the correct letter for month-of-year is M.
yyyy-MM-dd is the default format of java.time.LocalDate
The java.time API is based on ISO 8601 standards and therefore it does not require specifying a DateTimeFormatter explicitly to parse a date-time string if it is already in ISO 8601 format. Similarly, the toString implementation of a java.time type returns a string in ISO 8601 format. Check LocalDate#parse and LocalDate#toString for more information.
Ways to increment a local date by one day
There are three options:
LocalDate#plusDays(long daysToAdd)
LocalDate#plus(long amountToAdd, TemporalUnit unit): It has got some additional capabilities e.g. you can use it to increment a local date by days, weeks, months, years etc.
LocalDate#plus(TemporalAmount amountToAdd): You can specify a Period (or any other type implementing the TemporalAmount) to add.
Demo:
import java.time.Instant;
import java.time.LocalDate;
import java.time.Period;
import java.time.temporal.ChronoUnit;
public class Main {
public static void main(String[] args) {
// Parsing
LocalDate ldt = LocalDate.parse("2020-10-20");
System.out.println(ldt);
// Incrementing by one day
LocalDate oneDayLater = ldt.plusDays(1);
System.out.println(oneDayLater);
// Alternatively
oneDayLater = ldt.plus(1, ChronoUnit.DAYS);
System.out.println(oneDayLater);
oneDayLater = ldt.plus(Period.ofDays(1));
System.out.println(oneDayLater);
String desiredString = oneDayLater.toString();
System.out.println(desiredString);
}
}
Output:
2020-10-20
2020-10-21
2020-10-21
2020-10-21
2020-10-21
How to switch from the legacy to the modern date-time API?
You can switch from the legacy to the modern date-time API using Date#toInstant on a java-util-date instance. Once you have an Instant, you can easily obtain other date-time types of java.time API. An Instant represents a moment in time and is independent of a time-zone i.e. it represents a date-time in UTC (often displayed as Z which stands for Zulu-time and has a ZoneOffset of +00:00).
Demo:
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.OffsetDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
import java.util.Date;
public class Main {
public static void main(String[] args) {
Date date = new Date();
Instant instant = date.toInstant();
System.out.println(instant);
ZonedDateTime zdt = instant.atZone(ZoneId.of("Asia/Kolkata"));
System.out.println(zdt);
OffsetDateTime odt = instant.atOffset(ZoneOffset.of("+05:30"));
System.out.println(odt);
// Alternatively, using time-zone
odt = instant.atZone(ZoneId.of("Asia/Kolkata")).toOffsetDateTime();
System.out.println(odt);
LocalDateTime ldt = LocalDateTime.ofInstant(instant, ZoneId.of("Asia/Kolkata"));
System.out.println(ldt);
// Alternatively,
ldt = instant.atZone(ZoneId.of("Asia/Kolkata")).toLocalDateTime();
System.out.println(ldt);
}
}
Output:
2022-11-12T12:52:18.016Z
2022-11-12T18:22:18.016+05:30[Asia/Kolkata]
2022-11-12T18:22:18.016+05:30
2022-11-12T18:22:18.016+05:30
2022-11-12T18:22:18.016
2022-11-12T18:22:18.016
Learn more about the modern Date-Time API from Trail: Date Time.
Let's clarify the use case: You want to do calendar arithmetic and start/end with a java.util.Date.
Some approaches:
Convert to string and back with SimpleDateFormat: This is an inefficient solution.
Convert to LocalDate: You would lose any time-of-day information.
Convert to LocalDateTime: This involves more steps and you need to worry about timezone.
Convert to epoch with Date.getTime(): This is efficient but you are calculating with milliseconds.
Consider using java.time.Instant:
Date _now = new Date();
Instant _instant = _now.toInstant().minus(5, ChronoUnit.DAYS);
Date _newDate = Date.from(_instant);
You can do this just in one line.
e.g to add 5 days
Date newDate = Date.from(Date().toInstant().plus(5, ChronoUnit.DAYS));
to subtract 5 days
Date newDate = Date.from(Date().toInstant().minus(5, ChronoUnit.DAYS));

How do find day number(integer) of last day in the current month

I have specific date and i want to find last day number(integer) of month. I am using following code but always return current of date.
DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date date = (Date) sdf.parse(year+"-"+(month<10?("0"+month):month)+"-01");
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
calendar.add(Calendar.MONTH, 1);
calendar.set(Calendar.DAY_OF_MONTH, 1);
calendar.add(Calendar.DATE, -1);
Date dt = (Date) calendar.getTime(); -> dt is return current date always
example: my date = 2018/04/30 and i want to find 30.
I couldnt find answer at site.
Thnx
If using Java 8 (or higher), don't use Calendar. If using Java 6 or 7, you might want to consider using the ThreeTen Backport. In either case, use the Java Time API.
Using Java Time
Since input is int year and int month, use YearMonth.
To find last day number of month, call lengthOfMonth().
To get the date at the end of month, call atEndOfMonth().
Demo
int year = 2020;
int month = 2;
int lastDay = YearMonth.of(year, month).lengthOfMonth();
System.out.println(lastDay);
LocalDate date = YearMonth.of(year, month).atEndOfMonth();
System.out.println(date);
Output
29
2020-02-29
Using Joda-Time
If you don't have Java 8, and already use Joda-Time, do it this way:
Demo
int year = 2020;
int month = 2;
int lastDay = new LocalDate(year, month, 1).dayOfMonth().getMaximumValue();
System.out.println(lastDay);
LocalDate date = new LocalDate(year, month, 1).dayOfMonth().withMaximumValue();
System.out.println(date);
Output
29
2020-02-29
Using Calendar
If you insist on using Calendar, call getActualMaximum(Calendar.DAY_OF_MONTH) as also mentioned in other answers.
Since input is int year and int month, don't build and parse a string, just set Calendar fields directly. Note that "month" in Calendar is zero-based.
Demo
int year = 2020;
int month = 2;
Calendar calendar = Calendar.getInstance();
calendar.clear();
calendar.set(year, month - 1, 1);
int lastDay = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
calendar.set(Calendar.DAY_OF_MONTH, lastDay);
Date date = calendar.getTime();
System.out.println(lastDay);
System.out.printf("%tF%n", date);
Output
29
2020-02-29
have specific date and i want to find last day number(integer) of month
getActualMaximum() is what you are looking for here.
Calendar cal = Calendar.getInstance();
cal.setTime(parsedDate);
cal.getActualMaximum(Calendar.DAY_OF_MONTH);
Calendar calendar =Calendar.getInstance();
calendar.set(Calendar.DATE, 1);
calendar.roll(Calendar.DATE, -1);
int lastDate=calendar.get(Calendar.DATE);
You can use calendar for that, like this:
calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
Or, if you have joda, which is usually better:
DateTime d = new DateTame(dt);
d.dayOfMonth().getMaximumValue();
First, how are you getting the year to be used?
it should be simple by using Java Time LocalDate:
import java.time.*;
import static java.time.Month.*;
import static java.time.temporal.TemporalAdjusters.*;
import static java.time.temporal.ChronoField.*;
int lastDay = LocalDate.now() // or whatever date you want
.with(Month.of(yourMonth))
.with(lastDayOfMonth())
.get(DAY_OF_MONTH);
// or, if you have year and month, and want to find the corresponding last day
int lastDay = LocalDate.of(yourYear, yourMonth, 1)
.with(lastDayOfMonth())
.get(DAY_OF_MONTH);

How to reduce one month from current date and stored in date variable using java?

How to reduce one month from current date and want to sore in java.util.Date variable
im using this code but it's shows error in 2nd line
java.util.Date da = new Date();
da.add(Calendar.MONTH, -1); //error
How to store this date in java.util.Date variable?
Use Calendar:
Calendar cal = Calendar.getInstance();
cal.add(Calendar.MONTH, -1);
Date result = cal.getTime();
Starting from Java 8, the suggested way is to use the Date-Time API rather than Calendar.
If you want a Date object to be returned:
Date date = Date.from(ZonedDateTime.now().minusMonths(1).toInstant());
If you don't need exactly a Date object, you can use the classes directly, provided by the package, even to get dates in other time-zones:
ZonedDateTime dateInUTC = ZonedDateTime.now(ZoneId.of("Pacific/Auckland")).minusMonths(1);
Calendar calNow = Calendar.getInstance()
// adding -1 month
calNow.add(Calendar.MONTH, -1);
// fetching updated time
Date dateBeforeAMonth = calNow.getTime();
you can use Calendar
java.util.Date da = new Date();
Calendar cal = Calendar.getInstance();
cal.setTime(da);
cal.add(Calendar.MONTH, -1);
da = cal.getTime();
Using new java.time package in Java8 and Java9
import java.time.LocalDate;
LocalDate mydate = LocalDate.now(); // Or whatever you want
mydate = mydate.minusMonths(1);
The advantage to using this method is that you avoid all the issues about varying month lengths and have more flexibility in adjusting dates and ranges. The Local part also is Timezone smart so it's easy to convert between them.
As an aside, using java.time you can also get the day of the week, day of the month, all days up to the last of the month, all days up to a certain day of the week, etc.
mydate.plusMonths(1);
mydate.with(TemporalAdjusters.next(DayOfWeek.SUNDAY)).getDayOfMonth();
mydate.with(TemporalAdjusters.lastDayOfMonth());
Using JodaTime :
Date date = new DateTime().minusMonths(1).toDate();
JodaTime provides a convenient API for date manipulation.
Note that similar Date API will be introduced in JDK8 with the JSR310.
You can also use the DateUtils from apache common. The library also supports adding Hour, Minute, etc.
Date date = DateUtils.addMonths(new Date(), -1)
raduce 1 month of JDF
Date dateTo = new SimpleDateFormat("yyyy/MM/dd").parse(jdfMeTo.getJulianDate());
Calendar cal = Calendar.getInstance();
cal.setTime(dateTo);
cal.add(Calendar.MONTH, -1);
Date dateOf = cal.getTime();
Log.i("dateOf", dateOf.getTime() + "");
jdfMeOf.setJulianDate(cal.get(Calendar.DAY_OF_YEAR), cal.get(Calendar.DAY_OF_MONTH),
cal.get(Calendar.DAY_OF_WEEK_IN_MONTH));

last day of month calculation

I am having issues with the calculation of when the next Last Day of the Month is for a notification which is scheduled to be sent.
Here is my code:
RecurrenceFrequency recurrenceFrequency = notification.getRecurrenceFrequency();
Calendar nextNotifTime = Calendar.getInstance();
This is the line causing issues I believe:
nextNotifTime.add(recurrenceFrequency.getRecurrencePeriod(),
recurrenceFrequency.getRecurrenceOffset());
How can I use the Calendar to properly set the last day of the next month for the notification?
Calendar.getInstance().getActualMaximum(Calendar.DAY_OF_MONTH);
This returns actual maximum for current month. For example it is February of leap year now, so it returns 29 as int.
java.time.temporal.TemporalAdjusters.lastDayOfMonth()
Using the java.time library built into Java 8, you can use the TemporalAdjuster interface. We find an implementation ready for use in the TemporalAdjusters utility class: lastDayOfMonth.
import java.time.LocalDate;
import java.time.temporal.TemporalAdjusters;
LocalDate now = LocalDate.now(); //2015-11-23
LocalDate lastDay = now.with(TemporalAdjusters.lastDayOfMonth()); //2015-11-30
If you need to add time information, you may use any available LocalDate to LocalDateTime conversion like
lastDay.atStartOfDay(); //2015-11-30T00:00
And to get last day as Date object:
Calendar cal = Calendar.getInstance();
cal.set(Calendar.DATE, cal.getActualMaximum(Calendar.DATE));
Date lastDayOfMonth = cal.getTime();
You can set the calendar to the first of next month and then subtract a day.
Calendar nextNotifTime = Calendar.getInstance();
nextNotifTime.add(Calendar.MONTH, 1);
nextNotifTime.set(Calendar.DATE, 1);
nextNotifTime.add(Calendar.DATE, -1);
After running this code nextNotifTime will be set to the last day of the current month. Keep in mind if today is the last day of the month the net effect of this code is that the Calendar object remains unchanged.
Following will always give proper results:
Calendar cal = Calendar.getInstance();
cal.set(Calendar.MONTH, ANY_MONTH);
cal.set(Calendar.YEAR, ANY_YEAR);
cal.set(Calendar.DAY_OF_MONTH, 1);// This is necessary to get proper results
cal.set(Calendar.DATE, cal.getActualMaximum(Calendar.DATE));
cal.getTime();
You can also use YearMonth.
Like:
YearMonth.of(2019,7).atEndOfMonth()
YearMonth.of(2019,7).atDay(1)
See
https://docs.oracle.com/javase/8/docs/api/java/time/YearMonth.html#atEndOfMonth--
Using the latest java.time library here is the best solution:
LocalDate date = LocalDate.now();
LocalDate endOfMonth = date.with(TemporalAdjusters.lastDayOfMonth());
Alternatively, you can do:
LocalDate endOfMonth = date.withDayOfMonth(date.lengthOfMonth());
Look at the getActualMaximum(int field) method of the Calendar object.
If you set your Calendar object to be in the month for which you are seeking the last date, then getActualMaximum(Calendar.DAY_OF_MONTH) will give you the last day.
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
Date date = sdf.parse("11/02/2016");
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
System.out.println("First Day Of Month : " + calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
System.out.println("Last Day of Month : " + calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
Kotlin date extension implementation using java.util.Calendar
fun Date.toEndOfMonth(): Date {
return Calendar.getInstance().apply {
time = this#toEndOfMonth
}.toEndOfMonth().time
}
fun Calendar.toEndOfMonth(): Calendar {
set(Calendar.DAY_OF_MONTH, getActualMaximum(Calendar.DAY_OF_MONTH))
return this
}
You can call toEndOfMonth function on each Date object like Date().toEndOfMonth()

Look for an easy was to find a user selected date

I have a DatePickerDialog that opens up and you select the date. I want to find out what day that is. Monday Tuesday. You get the idea. I can get the date I just don't know how to find the day. Is there an easy was to do this? I have looked at the documentation on this and I don't see anything that is a getDay(int year, int date, int month) method. Is there one?
If you want to create localized strings from dates use SimpleDateFormat it will generate Strings from a Date object:
SimpleDayFormat dayFormatter = new SimpleDateFormat("E");
Log.d("Today", "Today is " + dayFormatter.format(new Date()));
http://www.exampledepot.com/egs/java.util/DayOfWeek.html suggests using Calendar.get(Calendar.DAY_OF_WEEK).
Calendar xmas = new GregorianCalendar(1998, Calendar.DECEMBER, 25);
int dayOfWeek = xmas.get(Calendar.DAY_OF_WEEK); // 6=Friday
Calendar cal = new GregorianCalendar(2003, Calendar.JANUARY, 1);
dayOfWeek = cal.get(Calendar.DAY_OF_WEEK); // 4=Wednesday

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