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How can we add or subtract date in java? For instance java.sql.Date and formatted like this: yyyy-MM-dd, how can i Add 5 months from that? I've seen in some tutorial that they are using Calendar, can we set date on it? Please Help.
Example: 2012-01-01 when added 5 months will become 2012-06-01.
PS: I'm a .Net Programmer and slowly learning to Java environment.
First of all you have to convert your String date to java.util.Date, than you have to use java.util.Calendar to manipulate dates. It is also possible to do math with millis, but I do not recommend this.
public static void main( final String[] args ) throws ParseException {
final String sdate = "2012-01-01";
final SimpleDateFormat df = new SimpleDateFormat( "yyyy-MM-dd" );
final Date date = df.parse( sdate ); // conversion from String
final java.util.Calendar cal = GregorianCalendar.getInstance();
cal.setTime( date );
cal.add( GregorianCalendar.MONTH, 5 ); // date manipulation
System.out.println( "result: " + df.format( cal.getTime() ) ); // conversion to String
}
Stear clear of the built-in Date class for date math. Take a look at JodaTime, which has a much better API for this kind of thing.
Use Calendar
Calendar cal = Calendar.getInstance();
cal.add(Calendar.MONTH, 5);
java.time
The accepted answer uses java.util date-time API and SimpleDateFormat which was the correct thing to do in 2012. In Mar 2014, the java.util date-time API and their formatting API, SimpleDateFormat were supplanted by the modern date-time API. Since then, it is highly recommended to stop using the legacy date-time API.
Solution using java.time, the modern date-time API:
You do not need a DateTimeFormatter for your date string: java.time API is based on ISO 8601 and therefore you do not need to specify a DateTimeFormatter to parse a date-time string which is already in ISO 8601 format e.g. your date string, 2012-01-01 which can be parsed directly into a LocalDate instance, that contains just date units.
Having parsed the date string into LocalDate, you can add or subtract different date units e.g. years, months, days etc. to it.
Demo:
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
class Main {
public static void main(String args[]) {
LocalDate date = LocalDate.parse("2012-01-01");
System.out.println(date);
LocalDate afterFiveMonths = date.plusMonths(5);
LocalDate beforeFiveMonths = date.minusMonths(5);
System.out.println(afterFiveMonths);
System.out.println(beforeFiveMonths);
// Alternatively,
afterFiveMonths = date.plus(5, ChronoUnit.MONTHS);
beforeFiveMonths = date.minus(5, ChronoUnit.MONTHS);
System.out.println(afterFiveMonths);
System.out.println(beforeFiveMonths);
}
}
Output:
2012-01-01
2012-06-01
2011-08-01
2012-06-01
2011-08-01
ONLINE DEMO
Learn more about the modern Date-Time API from Trail: Date Time.
To convert a Date to a Calendar, use:
Date date = your_date_here;
Calendar cal = Calendar.getInstance();
cal.setTime(date);
Then use the calendar arithmetic functions to add/subtract:
cal.add(Calendar.MONTH, 5);
Or, Convert the date to time in milis. Do the math, and convert the millis back to a date.
use CalenderUtils from google's package GWT.
import com.google.gwt.user.datepicker.client.CalendarUtil;
...
//now
Date d = new Date();
// Now + 2 months
CalendarUtil.addMonthsToDate(d, 2);
Another option is the DateUtils class from the 3rd party Apache Commons library collection. Example:
Date d = DateUtils.parseDate("2012-01-01", "yyyy-MM-dd");
Date d2 = DateUtils.addMonths(d, 5);
System.out.println("Old date + 5 months = " + d2);
There are various ways. One of them could be with joda.time.
This does not answer the question by using Calendar but one of the other approach if needed by someone. :D
import java.sql.Date;
import org.joda.time.DateTime;
//
DateTime datetime = new DateTime("2012-01-01");
Date dt = new Date(datetime.plusMonths(5).toDate().getTime());
System.out.println(dt);
// This gives output as 2012-06-01
PS: Happy coding with Java
The complete program that does date addition is in http://dwbitechguru.blogspot.ca/2014/09/jave-program-to-add-or-substract-dates.html
I am trying to add 17 days to 10-APR-2014 and convert the date to dd-MMM-yyyy format, but I am getting Sun Apr 27 00:00:00 GMT+05:30 2014.
Here is my code:
import java.util.*;
import java.text.*;
public class HelloWorld{
public static void main(String []args){
SimpleDateFormat sdf = new SimpleDateFormat("dd-MMM-yyyy");
Calendar c = Calendar.getInstance();
c.setTime(new Date());
c.add(Calendar.DATE, 17);
String output = sdf.format(c.getTime());
System.out.println(output);
System.out.print(new SimpleDateFormat("dd-MMM-yyyy").parse(output));
}
}
How can I make the output be 27-Apr-2014?
You are printing a Date parsed from a String formatted from the calendar date.
Instead, print the formatted calendar date:
System.out.print(new SimpleDateFormat("dd-MMM-yyyy").format(c.getTime()));
If displaying and using the dates is disjunct, do this:
Date date; // from Calendar or wherever
String str = new SimpleDateFormat("dd-MMM-yyyy").format(date));
// display str
Then when you want to do something with a selected date:
String selection;
Date date = new SimpleDateFormat("dd-MMM-yyyy").parse(selection));
// do something with date
The answer by Bohemian is correct. Here I present an alternative solution.
Avoid j.u.Date
The java.util.Date and .Calendar classes bundled with Java are notoriously troublesome. Avoid them. Use either Joda-Time or the new java.time package in Java 8.
Date-Only
If you need only a date, without any time component, both Joda-Time and java.time offer a LocalDate class.
Time Zone
Even for a date-only, you still need a time zone to get "today". At any moment the date may vary ±1 depending on your location on the globe. If you do not specify a time zone, the JVM's default time zone will be applied.
Example Code
Here is some example code in Joda-Time 2.3.
Determine "today" based on some time zone. Add seventeen days.
DateTimeZone timeZone = DateTimeZone.forID( "Asia/Kolkata" );
LocalDate today = new LocalDate( timeZone );
LocalDate seventeenDaysLater = today.plusDays( 17 );
Generate a String representation of the date-time value…
DateTimeFormatter formatter = DateTimeFormat.forPattern( "dd-MMM-yyyy" );
String output = formatter.print( seventeenDaysLater );
Dump to console…
System.out.println( "today: " + today );
System.out.println( "seventeenDaysLater: " + seventeenDaysLater );
System.out.println( "output: " + output );
When run…
today: 2014-04-21
seventeenDaysLater: 2014-05-08
output: 08-May-2014
How can we add or subtract date in java? For instance java.sql.Date and formatted like this: yyyy-MM-dd, how can i Add 5 months from that? I've seen in some tutorial that they are using Calendar, can we set date on it? Please Help.
Example: 2012-01-01 when added 5 months will become 2012-06-01.
PS: I'm a .Net Programmer and slowly learning to Java environment.
First of all you have to convert your String date to java.util.Date, than you have to use java.util.Calendar to manipulate dates. It is also possible to do math with millis, but I do not recommend this.
public static void main( final String[] args ) throws ParseException {
final String sdate = "2012-01-01";
final SimpleDateFormat df = new SimpleDateFormat( "yyyy-MM-dd" );
final Date date = df.parse( sdate ); // conversion from String
final java.util.Calendar cal = GregorianCalendar.getInstance();
cal.setTime( date );
cal.add( GregorianCalendar.MONTH, 5 ); // date manipulation
System.out.println( "result: " + df.format( cal.getTime() ) ); // conversion to String
}
Stear clear of the built-in Date class for date math. Take a look at JodaTime, which has a much better API for this kind of thing.
Use Calendar
Calendar cal = Calendar.getInstance();
cal.add(Calendar.MONTH, 5);
java.time
The accepted answer uses java.util date-time API and SimpleDateFormat which was the correct thing to do in 2012. In Mar 2014, the java.util date-time API and their formatting API, SimpleDateFormat were supplanted by the modern date-time API. Since then, it is highly recommended to stop using the legacy date-time API.
Solution using java.time, the modern date-time API:
You do not need a DateTimeFormatter for your date string: java.time API is based on ISO 8601 and therefore you do not need to specify a DateTimeFormatter to parse a date-time string which is already in ISO 8601 format e.g. your date string, 2012-01-01 which can be parsed directly into a LocalDate instance, that contains just date units.
Having parsed the date string into LocalDate, you can add or subtract different date units e.g. years, months, days etc. to it.
Demo:
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
class Main {
public static void main(String args[]) {
LocalDate date = LocalDate.parse("2012-01-01");
System.out.println(date);
LocalDate afterFiveMonths = date.plusMonths(5);
LocalDate beforeFiveMonths = date.minusMonths(5);
System.out.println(afterFiveMonths);
System.out.println(beforeFiveMonths);
// Alternatively,
afterFiveMonths = date.plus(5, ChronoUnit.MONTHS);
beforeFiveMonths = date.minus(5, ChronoUnit.MONTHS);
System.out.println(afterFiveMonths);
System.out.println(beforeFiveMonths);
}
}
Output:
2012-01-01
2012-06-01
2011-08-01
2012-06-01
2011-08-01
ONLINE DEMO
Learn more about the modern Date-Time API from Trail: Date Time.
To convert a Date to a Calendar, use:
Date date = your_date_here;
Calendar cal = Calendar.getInstance();
cal.setTime(date);
Then use the calendar arithmetic functions to add/subtract:
cal.add(Calendar.MONTH, 5);
Or, Convert the date to time in milis. Do the math, and convert the millis back to a date.
use CalenderUtils from google's package GWT.
import com.google.gwt.user.datepicker.client.CalendarUtil;
...
//now
Date d = new Date();
// Now + 2 months
CalendarUtil.addMonthsToDate(d, 2);
Another option is the DateUtils class from the 3rd party Apache Commons library collection. Example:
Date d = DateUtils.parseDate("2012-01-01", "yyyy-MM-dd");
Date d2 = DateUtils.addMonths(d, 5);
System.out.println("Old date + 5 months = " + d2);
There are various ways. One of them could be with joda.time.
This does not answer the question by using Calendar but one of the other approach if needed by someone. :D
import java.sql.Date;
import org.joda.time.DateTime;
//
DateTime datetime = new DateTime("2012-01-01");
Date dt = new Date(datetime.plusMonths(5).toDate().getTime());
System.out.println(dt);
// This gives output as 2012-06-01
PS: Happy coding with Java
The complete program that does date addition is in http://dwbitechguru.blogspot.ca/2014/09/jave-program-to-add-or-substract-dates.html
This question already has answers here:
How to get the current date and time
(10 answers)
Closed 2 years ago.
What's the best way to get the current date/time in Java?
It depends on what form of date / time you want:
If you want the date / time as a single numeric value, then System.currentTimeMillis() gives you that, expressed as the number of milliseconds after the UNIX epoch (as a Java long). This value is a delta from a UTC time-point, and is independent of the local time-zone1.
If you want the date / time in a form that allows you to access the components (year, month, etc) numerically, you could use one of the following:
new Date() gives you a Date object initialized with the current date / time. The problem is that the Date API methods are mostly flawed ... and deprecated.
Calendar.getInstance() gives you a Calendar object initialized with the current date / time, using the default Locale and TimeZone. Other overloads allow you to use a specific Locale and/or TimeZone. Calendar works ... but the APIs are still cumbersome.
new org.joda.time.DateTime() gives you a Joda-time object initialized with the current date / time, using the default time zone and chronology. There are lots of other Joda alternatives ... too many to describe here. (But note that some people report that Joda time has performance issues.; e.g. https://stackoverflow.com/questions/6280829.)
in Java 8, calling java.time.LocalDateTime.now() and java.time.ZonedDateTime.now() will give you representations2 for the current date / time.
Prior to Java 8, most people who know about these things recommended Joda-time as having (by far) the best Java APIs for doing things involving time point and duration calculations.
With Java 8 and later, the standard java.time package is recommended. Joda time is now considered "obsolete", and the Joda maintainers are recommending that people migrate.3.
1 - System.currentTimeMillis() gives the "system" time. While it is normal practice for the system clock to be set to (nominal) UTC, there will be a difference (a delta) between the local UTC clock and true UTC. The size of the delta depends on how well (and how often) the system's clock is synced with UTC.
2 - Note that LocalDateTime doesn't include a time zone. As the javadoc says: "It cannot represent an instant on the time-line without additional information such as an offset or time-zone."
3 - Note: your Java 8 code won't break if you don't migrate, but the Joda codebase may eventually stop getting bug fixes and other patches. As of 2020-02, an official "end of life" for Joda has not been announced, and the Joda APIs have not been marked as Deprecated.
(Attention: only for use with Java versions <8. For Java 8+ check other replies.)
If you just need to output a time stamp in format YYYY.MM.DD-HH.MM.SS (very frequent case) then here's the way to do it:
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(Calendar.getInstance().getTime());
If you want the current date as String, try this:
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date date = new Date();
System.out.println(dateFormat.format(date));
or
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Calendar cal = Calendar.getInstance();
System.out.println(dateFormat.format(cal.getTime()));
http://www.mkyong.com/java/java-how-to-get-current-date-time-date-and-calender/
tl;dr
Instant.now() // Capture the current moment in UTC, with a resolution of nanoseconds. Returns a `Instant` object.
… or …
ZonedDateTime.now( // Capture the current moment as seen in…
ZoneId.of( "America/Montreal" ) // … the wall-clock time used by the people of a particular region (a time zone).
) // Returns a `ZonedDateTime` object.
java.time
A few of the Answers mention that java.time classes are the modern replacement for the troublesome old legacy date-time classes bundled with the earliest versions of Java. Below is a bit more information.
Time zone
The other Answers fail to explain how a time zone is crucial in determining the current date and time. For any given moment, the date and the time vary around the globe by zone. For example, a few minutes after midnight is a new day in Paris France while still being “yesterday” in Montréal Québec.
Instant
Much of your business logic and data storage/exchange should be done in UTC, as a best practice.
To get the current moment in UTC with a resolution in nanoseconds, use Instant class. Conventional computer hardware clocks are limited in their accuracy, so the current moment may be captured in milliseconds or microseconds rather than nanoseconds.
Instant instant = Instant.now();
ZonedDateTime
You can adjust that Instant into other time zones. Apply a ZoneId object to get a ZonedDateTime.
ZoneId z = ZoneId.of( "America/Montreal" );
ZonedDateTime zdt = instant.atZone( z );
We can skip the Instant and get the current ZonedDateTime directly.
ZonedDateTime zdt = ZonedDateTime.now( z );
Always pass that optional time zone argument. If omitted, your JVM’s current default time zone is applied. The default can change at any moment, even during runtime. Do not subject your app to an externality out of your control. Always specify the desired/expected time zone.
ZonedDateTime do_Not_Do_This = ZonedDateTime.now(); // BAD - Never rely implicitly on the current default time zone.
You can later extract an Instant from the ZonedDateTime.
Instant instant = zdt.toInstant();
Always use an Instant or ZonedDateTime rather than a LocalDateTime when you want an actual moment on the timeline. The Local… types purposely have no concept of time zone so they represent only a rough idea of a possible moment. To get an actual moment you must assign a time zone to transform the Local… types into a ZonedDateTime and thereby make it meaningful.
LocalDate
The LocalDate class represents a date-only value without time-of-day and without time zone.
ZoneId z = ZoneId.of( "America/Montreal" );
LocalDate today = LocalDate.now( z ); // Always pass a time zone.
Strings
To generate a String representing the date-time value, simply call toString on the java.time classes for the standard ISO 8601 formats.
String output = myLocalDate.toString(); // 2016-09-23
… or …
String output = zdt.toString(); // 2016-09-23T12:34:56.789+03:00[America/Montreal]
The ZonedDateTime class extends the standard format by wisely appending the name of the time zone in square brackets.
For other formats, search Stack Overflow for many Questions and Answers on the DateTimeFormatter class.
Avoid LocalDateTime
Contrary to the comment on the Question by RamanSB, you should not use LocalDateTime class for the current date-time.
The LocalDateTime purposely lacks any time zone or offset-from-UTC information. So, this is not appropriate when you are tracking a specific moment on the timeline. Certainly not appropriate for capturing the current moment.
A LocalDateTime has only a date and a time-of-day such as "noon on 23rd of January 2020", but we have no idea if that is noon in Tokyo Japan or noon in Toledo Ohio US, two different moments many hours apart.
The “Local” wording is counter-intuitive. It means any locality rather than any one specific locality. For example Christmas this year starts at midnight on the 25th of December: 2017-12-25T00:00:00, to be represented as a LocalDateTime. But this means midnight at various points around the globe at different times. Midnight happens first in Kiribati, later in New Zealand, hours more later in India, and so on, with several more hours passing before Christmas begins in France when the kids in Canada are still awaiting that day. Each one of these Christmas-start points would be represented as a separate ZonedDateTime.
From outside your system
If you cannot trust your system clock, see Java: Get current Date and Time from Server not System clock and my Answer.
java.time.Clock
To harness an alternate supplier of the current moment, write a subclass of the abstract java.time.Clock class.
You can pass your Clock implementation as an argument to the various java.time methods. For example, Instant.now( clock ).
Instant instant = Instant.now( yourClockGoesHere ) ;
For testing purposes, note the alternate implementations of Clock available statically from Clock itself: fixed, offset, tick, and more.
About java.time
The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.
Where to obtain the java.time classes?
Java SE 8, Java SE 9, Java SE 10, Java SE 11, and later - Part of the standard Java API with a bundled implementation.
Java 9 adds some minor features and fixes.
Java SE 6 and Java SE 7
Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
Later versions of Android bundle implementations of the java.time classes.
For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….
The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.
In Java 8 it is:
LocalDateTime.now()
and in case you need time zone info:
ZonedDateTime.now()
and in case you want to print fancy formatted string:
System.out.println(ZonedDateTime.now().format(DateTimeFormatter.RFC_1123_DATE_TIME))
Just create a Date object...
import java.util.Date;
Date date = new Date();
// 2015/09/27 15:07:53
System.out.println( new SimpleDateFormat("yyyy/MM/dd HH:mm:ss").format(Calendar.getInstance().getTime()) );
// 15:07:53
System.out.println( new SimpleDateFormat("HH:mm:ss").format(Calendar.getInstance().getTime()) );
// 09/28/2015
System.out.println(new SimpleDateFormat("MM/dd/yyyy").format(Calendar.getInstance().getTime()));
// 20150928_161823
System.out.println( new SimpleDateFormat("yyyyMMdd_HHmmss").format(Calendar.getInstance().getTime()) );
// Mon Sep 28 16:24:28 CEST 2015
System.out.println( Calendar.getInstance().getTime() );
// Mon Sep 28 16:24:51 CEST 2015
System.out.println( new Date(System.currentTimeMillis()) );
// Mon Sep 28
System.out.println( new Date().toString().substring(0, 10) );
// 2015-09-28
System.out.println( new java.sql.Date(System.currentTimeMillis()) );
// 14:32:26
Date d = new Date();
System.out.println( (d.getTime() / 1000 / 60 / 60) % 24 + ":" + (d.getTime() / 1000 / 60) % 60 + ":" + (d.getTime() / 1000) % 60 );
// 2015-09-28 17:12:35.584
System.out.println( new Timestamp(System.currentTimeMillis()) );
// Java 8
// 2015-09-28T16:16:23.308+02:00[Europe/Belgrade]
System.out.println( ZonedDateTime.now() );
// Mon, 28 Sep 2015 16:16:23 +0200
System.out.println( ZonedDateTime.now().format(DateTimeFormatter.RFC_1123_DATE_TIME) );
// 2015-09-28
System.out.println( LocalDate.now(ZoneId.of("Europe/Paris")) ); // rest zones id in ZoneId class
// 16
System.out.println( LocalTime.now().getHour() );
// 2015-09-28T16:16:23.315
System.out.println( LocalDateTime.now() );
Use:
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(Calendar.getInstance().getTime());
System.out.println(timeStamp );
(It's working.)
There are many different methods:
System.currentTimeMillis()
Date
Calendar
Create object of date and simply print it down.
Date d = new Date(System.currentTimeMillis());
System.out.print(d);
java.util.Date date = new java.util.Date();
It's automatically populated with the time it's instantiated.
Similar to above solutions. But I always find myself looking for this chunk of code:
Date date=Calendar.getInstance().getTime();
System.out.println(date);
For java.util.Date, just create a new Date()
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date date = new Date();
System.out.println(dateFormat.format(date)); //2016/11/16 12:08:43
For java.util.Calendar, uses Calendar.getInstance()
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Calendar cal = Calendar.getInstance();
System.out.println(dateFormat.format(cal)); //2016/11/16 12:08:43
For java.time.LocalDateTime, uses LocalDateTime.now()
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy/MM/dd HH:mm:ss");
LocalDateTime now = LocalDateTime.now();
System.out.println(dtf.format(now)); //2016/11/16 12:08:43
For java.time.LocalDate, uses LocalDate.now()
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy/MM/dd");
LocalDate localDate = LocalDate.now();
System.out.println(dtf.format(localDate)); //2016/11/16
Reference: https://www.mkyong.com/java/java-how-to-get-current-date-time-date-and-calender/
1st Understand the java.util.Date class
1.1 How to obtain current Date
import java.util.Date;
class Demostration{
public static void main(String[]args){
Date date = new Date(); // date object
System.out.println(date); // Try to print the date object
}
}
1.2 How to use getTime() method
import java.util.Date;
public class Main {
public static void main(String[]args){
Date date = new Date();
long timeInMilliSeconds = date.getTime();
System.out.println(timeInMilliSeconds);
}
}
This will return the number of milliseconds since January 1, 1970, 00:00:00 GMT for time comparison purposes.
1.3 How to format time using SimpleDateFormat class
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
class Demostration{
public static void main(String[]args){
Date date=new Date();
DateFormat dateFormat=new SimpleDateFormat("yyyy-MM-dd");
String formattedDate=dateFormat.format(date);
System.out.println(formattedDate);
}
}
Also try using different format patterns like "yyyy-MM-dd hh:mm:ss" and select desired pattern. http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html
2nd Understand the java.util.Calendar class
2.1 Using Calendar Class to obtain current time stamp
import java.util.Calendar;
class Demostration{
public static void main(String[]args){
Calendar calendar=Calendar.getInstance();
System.out.println(calendar.getTime());
}
}
2.2 Try using setTime and other set methods for set calendar to different date.
Source: http://javau91.blogspot.com/
Have you looked at java.util.Date? It is exactly what you want.
Java 8 or above
LocalDateTime.now() and ZonedDateTime.now()
I find this to be the best way:
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Calendar cal = Calendar.getInstance();
System.out.println(dateFormat.format(cal.getTime())); // 2014/08/06 16:00:22
Have a look at the Date class. There's also the newer Calendar class which is the preferred method of doing many date / time operations (a lot of the methods on Date have been deprecated.)
If you just want the current date, then either create a new Date object or call Calendar.getInstance();.
As mentioned the basic Date() can do what you need in terms of getting the current time. In my recent experience working heavily with Java dates there are a lot of oddities with the built in classes (as well as deprecation of many of the Date class methods). One oddity that stood out to me was that months are 0 index based which from a technical standpoint makes sense, but in real terms can be very confusing.
If you are only concerned with the current date that should suffice - however if you intend to do a lot of manipulating/calculations with dates it could be very beneficial to use a third party library (so many exist because many Java developers have been unsatisfied with the built in functionality).
I second Stephen C's recommendation as I have found Joda-time to be very useful in simplifying my work with dates, it is also very well documented and you can find many useful examples throughout the web. I even ended up writing a static wrapper class (as DateUtils) which I use to consolidate and simplify all of my common date manipulation.
Use:
SimpleDateFormat sdf = new SimpleDateFormat("yyyy:MM:dd::HH:mm:ss");
System.out.println(sdf.format(System.currentTimeMillis()));
The print statement will print the time when it is called and not when the SimpleDateFormat was created. So it can be called repeatedly without creating any new objects.
System.out.println( new SimpleDateFormat("yyyy:MM:dd - hh:mm:ss a").format(Calendar.getInstance().getTime()) );
//2018:02:10 - 05:04:20 PM
date/time with AM/PM
New Data-Time API is introduced with the dawn of Java 8. This is due
to following issues that were caused in the old data-time API.
Difficult to handle time zone : need to write lot of code to deal with
time zones.
Not Thread Safe : java.util.Date is not thread safe.
So have a look around with Java 8
import java.time.LocalDate;
import java.time.LocalTime;
import java.time.LocalDateTime;
import java.time.Month;
public class DataTimeChecker {
public static void main(String args[]) {
DataTimeChecker dateTimeChecker = new DataTimeChecker();
dateTimeChecker.DateTime();
}
public void DateTime() {
// Get the current date and time
LocalDateTime currentTime = LocalDateTime.now();
System.out.println("Current DateTime: " + currentTime);
LocalDate date1 = currentTime.toLocalDate();
System.out.println("Date : " + date1);
Month month = currentTime.getMonth();
int day = currentTime.getDayOfMonth();
int seconds = currentTime.getSecond();
System.out.println("Month : " + month);
System.out.println("Day : " + day);
System.out.println("Seconds : " + seconds);
LocalDateTime date2 = currentTime.withDayOfMonth(17).withYear(2018);
System.out.println("Date : " + date2);
//Prints 17 May 2018
LocalDate date3 = LocalDate.of(2018, Month.MAY, 17);
System.out.println("Date : " + date3);
//Prints 04 hour 45 minutes
LocalTime date4 = LocalTime.of(4, 45);
System.out.println("Date : " + date4);
// Convert to a String
LocalTime date5 = LocalTime.parse("20:15:30");
System.out.println("Date : " + date5);
}
}
Output of the coding above :
Current DateTime: 2018-05-17T04:40:34.603
Date : 2018-05-17
Month : MAY
Day : 17
Seconds : 34
Date : 2018-05-17T04:40:34.603
Date : 2018-05-17
Date : 04:45
Date : 20:15:30
I created this methods, it works for me...
public String GetDay() {
return String.valueOf(LocalDateTime.now().format(DateTimeFormatter.ofPattern("dd")));
}
public String GetNameOfTheDay() {
return String.valueOf(LocalDateTime.now().getDayOfWeek());
}
public String GetMonth() {
return String.valueOf(LocalDateTime.now().format(DateTimeFormatter.ofPattern("MM")));
}
public String GetNameOfTheMonth() {
return String.valueOf(LocalDateTime.now().getMonth());
}
public String GetYear() {
return String.valueOf(LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy")));
}
public boolean isLeapYear(long year) {
return Year.isLeap(year);
}
public String GetDate() {
return GetDay() + "/" + GetMonth() + "/" + GetYear();
}
public String Get12HHour() {
return String.valueOf(LocalDateTime.now().format(DateTimeFormatter.ofPattern("hh")));
}
public String Get24HHour() {
return String.valueOf(LocalDateTime.now().getHour());
}
public String GetMinutes() {
return String.valueOf(LocalDateTime.now().format(DateTimeFormatter.ofPattern("mm")));
}
public String GetSeconds() {
return String.valueOf(LocalDateTime.now().format(DateTimeFormatter.ofPattern("ss")));
}
public String Get24HTime() {
return Get24HHour() + ":" + GetMinutes();
}
public String Get24HFullTime() {
return Get24HHour() + ":" + GetMinutes() + ":" + GetSeconds();
}
public String Get12HTime() {
return Get12HHour() + ":" + GetMinutes();
}
public String Get12HFullTime() {
return Get12HHour() + ":" + GetMinutes() + ":" + GetSeconds();
}
import java.util.*;
import java.text.*;
public class DateDemo {
public static void main(String args[]) {
Date dNow = new Date( );
SimpleDateFormat ft =
new SimpleDateFormat ("E yyyy.MM.dd 'at' hh:mm:ss a zzz");
System.out.println("Current Date: " + ft.format(dNow));
}
}
you can use date for fet current data. so using SimpleDateFormat get format
just try this code:
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class CurrentTimeDateCalendar {
public static void getCurrentTimeUsingDate() {
Date date = new Date();
String strDateFormat = "hh:mm:ss a";
DateFormat dateFormat = new SimpleDateFormat(strDateFormat);
String formattedDate= dateFormat.format(date);
System.out.println("Current time of the day using Date - 12 hour format: " + formattedDate);
}
public static void getCurrentTimeUsingCalendar() {
Calendar cal = Calendar.getInstance();
Date date=cal.getTime();
DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
String formattedDate=dateFormat.format(date);
System.out.println("Current time of the day using Calendar - 24 hour format: "+ formattedDate);
}
}
which the sample output is:
Current time of the day using Date - 12 hour format: 11:13:01 PM
Current time of the day using Calendar - 24 hour format: 23:13:01
more information on:
Getting Current Date Time in Java
Current Date using java 8:
First, let's use java.time.LocalDate to get the current system date:
LocalDate localDate = LocalDate.now();
To get the date in any other timezone we can use LocalDate.now(ZoneId):
LocalDate localDate = LocalDate.now(ZoneId.of("GMT+02:30"));
We can also use java.time.LocalDateTime to get an instance of LocalDate:
LocalDateTime localDateTime = LocalDateTime.now();
LocalDate localDate = localDateTime.toLocalDate();
You can use Date object and format by yourself. It is hard to format and need more codes, as a example,
Date dateInstance = new Date();
int year = dateInstance.getYear()+1900;//Returns:the year represented by this date, minus 1900.
int date = dateInstance.getDate();
int month = dateInstance.getMonth();
int day = dateInstance.getDay();
int hours = dateInstance.getHours();
int min = dateInstance.getMinutes();
int sec = dateInstance.getSeconds();
String dayOfWeek = "";
switch(day){
case 0:
dayOfWeek = "Sunday";
break;
case 1:
dayOfWeek = "Monday";
break;
case 2:
dayOfWeek = "Tuesday";
break;
case 3:
dayOfWeek = "Wednesday";
break;
case 4:
dayOfWeek = "Thursday";
break;
case 5:
dayOfWeek = "Friday";
break;
case 6:
dayOfWeek = "Saturday";
break;
}
System.out.println("Date: " + year +"-"+ month + "-" + date + " "+ dayOfWeek);
System.out.println("Time: " + hours +":"+ min + ":" + sec);
output:
Date: 2017-6-23 Sunday
Time: 14:6:20
As you can see this is the worst way you can do it and according to oracle documentation it is deprecated.
Oracle doc:
The class Date represents a specific instant in time, with millisecond
precision.
Prior to JDK 1.1, the class Date had two additional functions. It
allowed the interpretation of dates as year, month, day, hour, minute,
and second values. It also allowed the formatting and parsing of date
strings. Unfortunately, the API for these functions was not amenable
to internationalization. As of JDK 1.1, the Calendar class should be
used to convert between dates and time fields and the DateFormat class
should be used to format and parse date strings. The corresponding
methods in Date are deprecated.
So alternatively, you can use Calendar class,
Calendar.YEAR;
//and lot more
To get current time, you can use:
Calendar rightNow = Calendar.getInstance();
Doc:
Like other locale-sensitive classes, Calendar provides a class method,
getInstance, for getting a generally useful object of this type.
Calendar's getInstance method returns a Calendar object whose calendar
fields have been initialized with the current date and time
Below code for to get only date
Date rightNow = Calendar.getInstance().getTime();
System.out.println(rightNow);
Also, Calendar class have Subclasses. GregorianCalendar is a one of them and concrete subclass of Calendar and provides the standard calendar system used by most of the world.
Example using GregorianCalendar:
Calendar cal = new GregorianCalendar();
int hours = cal.get(Calendar.HOUR);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
int ap = cal.get(Calendar.AM_PM);
String amVSpm;
if(ap == 0){
amVSpm = "AM";
}else{
amVSpm = "PM";
}
String timer = hours + "-" + minute + "-" + second + " " +amVSpm;
System.out.println(timer);
You can use SimpleDateFormat, simple and quick way to format date:
String pattern = "yyyy-MM-dd";
SimpleDateFormat simpleDateFormat = new SimpleDateFormat(pattern);
String date = simpleDateFormat.format(new Date());
System.out.println(date);
Read this Jakob Jenkov tutorial: Java SimpleDateFormat.
As others mentioned, when we need to do manipulation from dates, we didn't had simple and best way or we couldn't satisfied built in classes, APIs.
As a example, When we need to get different between two dates, when we need to compare two dates(there is in-built method also for this) and many more. We had to use third party libraries. One of the good and popular one is Joda Time.
Also read:
How to get properly current date and time in Joda-Time?
JodaTime - how to get current time in UTC
Examples for JodaTime.
Download Joda
.
The happiest thing is now(in java 8), no one need to download and use libraries for any reasons. A simple example to get current date & time in Java 8,
LocalTime localTime = LocalTime.now();
System.out.println(localTime);
//with time zone
LocalTime localTimeWtZone = LocalTime.now(ZoneId.of("GMT+02:30"));
System.out.println(localTimeWtZone);
One of the good blog post to read about Java 8 date.
And keep remeber to find out more about Java date and time because there is lot more ways and/or useful ways that you can get/use.
Oracle tutorials for date & time.
Oracle tutorials for formatter.
Lesson: Standard Calendar.
EDIT:
According to #BasilBourque comment, the troublesome old date-time classes such as java.util.Date, java.util.Calendar, and java.text.SimpleTextFormat are now legacy, supplanted by the java.time classes.
I'll go ahead and throw this answer in because it is all I needed when I had the same question:
Date currentDate = new Date(System.currentTimeMillis());
currentDate is now your current date in a Java Date object.
One of our customers wants to be able to enter a date with only 2 digits for the year component. The date will be in the past, so we want it to work for the previous century if the 2 digit year is after the current year, but work for the current century if the 2 digit year is equal to or less than the current year.
as of today 10/30/2008
01/01/01 = 01/01/2001
01/01/09 = 01/01/1909
This is a strange requirement, and I solved the problem, I just don't like my solution.
It feels like there is a better way to do this.
Thanks for the help.
public static String stupidDate(String dateString)
{
String twoDigitYear = StringUtils.right(dateString, 2);
String newDate = StringUtils.left(dateString, dateString.length() - 2);
int year = NumberUtils.toInt(twoDigitYear);
Calendar c = GregorianCalendar.getInstance();
int centuryInt = c.get(Calendar.YEAR) - year;
newDate = newDate + StringUtils.left(Integer.toString(centuryInt), 2) + twoDigitYear;
return newDate;
}
Groovy script (easy enough to throw into java) demonstrating the point #bobince made about SimpleDateFormat.
import java.text.SimpleDateFormat
SimpleDateFormat sdf = new SimpleDateFormat('MM/dd/yy')
SimpleDateFormat fmt = new SimpleDateFormat('yyyy-MM-dd')
Calendar cal = Calendar.getInstance()
cal.add(Calendar.YEAR, -100)
sdf.set2DigitYearStart(cal.getTime())
dates = ['01/01/01', '10/30/08','01/01/09']
dates.each {String d ->
println fmt.format(sdf.parse(d))
}
Yields
2001-01-01
2008-10-30
1909-01-01
SimpleDateFormat already does two-digit year parsing for you, using the two-letter ‘yy’ format. (It'll still allow four digits, obviously.)
By default it uses now-80→now+20, so it's not exactly the same rule you propose, but it's reasonable and standardised (in the Java world at least), and can be overridden using set2DigitYearStart() if you want.
DateFormat informat= new SimpleDateFormat("MM/dd/yy");
DateFormat outformat= new SimpleDateFormat("MM/dd/yyyy");
return outformat.format(informat.parse(dateString));
In the longer term, try to migrate to ISO8601 date formatting (yyyy-MM-dd), because MM/dd/yy is approximately the worst possible date format and is bound to cause problems eventually.
How about this:
public static String anEasierStupidDateWithNoStringParsing(String dateString) {
DateFormat df = new SimpleDateFormat("MM/dd/yyyy");
//handling ParseExceptions is an exercise left to the reader!
Date date = df.parse(dateString);
Calendar cal = Calendar.getInstance();
cal.setTime(date);
Calendar now = Calendar.getInstance();
if (cal.after(now)) {
cal.add(Calendar.YEAR, -100);
}
return cal;
}
In other words, let SimpleDateFormat parse the String and just adjust the year to be the previous century if SimpleDateFormat (which has it's own rules for interpreting year strings) returns a date that is after the current date.
This would guarantee that all dates returned are in the past. However, it doesn't account for any dates that might be parsed as before this past century - for example, with the format MM/dd/yyyy, a date string like "01/11/12" parses to Jan 11, 12 A.D.
If Joda Time is an option:
String inputDate = "01/01/08";
// assuming U.S. style date, since it's not clear from your original question
DateTimeFormatter parser = DateTimeFormat.forPattern("MM/dd/yy");
DateTime dateTime = parser.parseDateTime(inputDate);
// if after current time
if (dateTime.isAfter(new DateTime())) {
dateTime = dateTime.minus(Years.ONE);
}
return dateTime.toString("MM/dd/yyyy");
I know Joda Time isn't part of Java SE, and as I've said in another thread, I usually do not condone using a third-party library when there's a Java library that does the same thing. However, the person who is developing Joda Time is also leading JSR310 - the Date and Time API that'll make it into Java 7. So I Joda Time is basically going to be in future Java releases.
The accepted answer uses legacy date-time API which was the correct thing to do in 2008 when the question was asked. In March 2014, java.time API supplanted the error-prone legacy date-time API. Since then, it has been strongly recommended to use this modern date-time API.
java.time API
You can put optional patterns between DateTimeFormatterBuilder#optionalStart and DateTimeFormatterBuilder#optionalEnd and create a formatter which can parse a date string with either a four-digit year or a two-digit year.
Using the DateTimeFormatterBuilder#appendValueReduced, you can specify a base value for the year as per your requirement.
Demo:
import java.time.LocalDate;
import java.time.Year;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.time.temporal.ChronoField;
import java.util.Locale;
import java.util.stream.Stream;
public class Main {
public static void main(String[] args) {
DateTimeFormatter parser = new DateTimeFormatterBuilder()
.appendPattern("M/d/")
.optionalStart()
.appendPattern("uuuu")
.optionalEnd()
.optionalStart()
.appendValueReduced(ChronoField.YEAR, 2, 2, Year.now().minusYears(100).getValue())
.optionalEnd()
.toFormatter(Locale.ENGLISH);
// Test
Stream.of(
"1/2/2022",
"01/2/2022",
"1/02/2022",
"01/02/2022",
"1/2/22",
"1/2/21",
"1/2/20",
"1/2/23",
"1/2/24"
)
.map(s -> LocalDate.parse(s, parser))
.forEach(System.out::println);
}
}
Output:
2022-01-02
2022-01-02
2022-01-02
2022-01-02
1922-01-02
2021-01-02
2020-01-02
1923-01-02
1924-01-02
Note that the dates with a two-digit year greater than the current year are parsed into a LocalDate with the last century.
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:
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:
2022-11-20T20:32:42.823Z
2022-11-21T02:02:42.823+05:30[Asia/Kolkata]
2022-11-21T02:02:42.823+05:30
2022-11-21T02:02:42.823+05:30
2022-11-21T02:02:42.823
2022-11-21T02:02:42.823
Learn more about the modern Date-Time API from Trail: Date Time.
Date deliverDate = new SimpleDateFormat("MM/dd/yy").parse(deliverDateString);
String dateString2 = new SimpleDateFormat("yyyy-MM-dd").format(deliverDate);
Working for me.