Java Date

In Java Programming there are available many package. This package are providing classes those are given functionality to implement date and time. In this section are given examples to use date and time API.

java.util.Date

import java.util.Date; //for LocalDate
public class MyDate{
    public static void main(String[] args){
      Date date=new Date();  
      System.out.println(date);  
    }
}

Mon Jul 22 09:47:01 IST 2019

Private instance variable of date objects are accessible within the private and public methods of Date class. In below table are mention all public methods which is accessible by Date objects.

java.time.LocalDate

Java java.time package are provide various class to deal with date and time. Let see an example to display simple date.

//Display Current date
import java.time.LocalDate; //for LocalDate
public class MyDate{
    public static void main(String[] args){
      //Create objects of LocalDate
      LocalDate date = LocalDate.now();

      System.out.println("Data : "+date);
    }
}

Data : 2019-07-21

That is very simple example the result are displayed in format of Year-Month-Day. There are following public methods are accessible within LocalDate class.

For example

//Display Current date
import java.time.LocalDate; //for LocalDate
public class MyDate{
    public static void main(String[] args){
      //Create objects of LocalDate
      LocalDate date = LocalDate.now();
      System.out.println("Day : "+date.getDayOfMonth());
      System.out.println("Month : "+date.getMonth());
      System.out.println("Year : "+date.getYear());
    }
}

Day : 4
Month : JULY
Year : 2019

java.time.LocalDateTime

In case, you'll are need to find exact date and time then you can use java.time.LocalDateTime package.

import java.time.LocalDateTime; //for LocalDateTime
public class MyDate{
    public static void main(String[] args){
      //Create objects of LocalDateTime
      LocalDateTime dateTime = LocalDateTime.now();

      System.out.println("Data and Time : "+dateTime);
    }
}

Data and Time : 2019-07-04T04:48:44.736

There are following public methods are accessible within java.time.LocalDateTime.

java.time.LocalTime

If In case you'll are only need to get the current time. Then you can use java.time.LocalTime package.

import java.time.LocalTime;; //for LocalTime
public class MyDate{
    public static void main(String[] args){
      //Create objects of LocalTime
      LocalTime time = LocalTime.now();

      System.out.println("Time : "+time);
    }
}

Time : 16:34:55.096

Method which is publicly accessible in java.time.LocalTime package.

Time format hour:minute:second. java.time package classes is based on ISO standards.

import java.time.LocalTime;; //for LocalTime
public class MyDate{
    public static void main(String[] args){
      //Create objects of LocalTime
      LocalTime time = LocalTime.now();

      System.out.println(" Time : "+time);
      System.out.println(" Add 5000 Nanosecond : "+time.plusNanos(5000));
      System.out.println(" Add 60 Second  : "+time.plusSeconds(60));
      System.out.println(" Add 5 Minutes : "+time.plusMinutes(5));
      System.out.println(" Add 10 Hours : "+time.plusHours(10));
      System.out.println(" Minus 1000000 Nanosecond : "+time.minusNanos(1000000));
      System.out.println(" Minus 60 Seconds : "+time.minusSeconds(60));
      System.out.println(" Minus 10 Minutes : "+time.minusMinutes(10));
      System.out.println(" Minus 4 Hours : "+time.minusHours(4));
    }
}

 Time : 07:48:15.611
 Add 5000 Nanosecond : 07:48:15.611005
 Add 60 Second  : 07:49:15.611
 Add 5 Minutes : 07:53:15.611
 Add 10 Hours : 17:48:15.611
 Minus 1000000 Nanosecond : 07:48:15.610
 Minus 60 Seconds : 07:47:15.611
 Minus 10 Minutes : 07:38:15.611
 Minus 4 Hours : 03:48:15.611

Date Time Conversion

Given of year and total days find the date

import java.time.LocalDate; //for LocalDate
public class MyDate{
    public static void main(String[] args){
      
      LocalDate date = LocalDate.ofYearDay(2020,50);
      System.out.println(date); //2020-02-19
    }
}

2020-02-19

Mathematical calculation of current date

import java.time.LocalDate; //for LocalDate
public class MyDate{
    public static void main(String[] args){
      //Create objects of LocalDate
      LocalDate date = LocalDate.now();

      System.out.println("Inital Data : "+date);

      System.out.println("Add 10 Days : "+date.plusDays(10));

      System.out.println("Minus 10 Days : "+date.minusDays(10));

      System.out.println("Add 3 Weeks : "+date.plusWeeks(3));

      System.out.println("Minus 3 Weeks : "+date.minusWeeks(3));

      System.out.println("Add 3 Months : "+date.plusMonths(3));

      System.out.println("Minus 3 Months : "+date.minusMonths(3));

      System.out.println("Add 3 Years : "+date.plusYears(3));

      System.out.println("Minus 3 Years : "+date.minusYears(3));
    }
}

Inital Data : 2019-07-04
Add 10 Days : 2019-07-14
Minus 10 Days : 2019-06-24
Add 3 Weeks : 2019-07-25
Minus 3 Weeks : 2019-06-13
Add 3 Months : 2019-10-04
Minus 3 Months : 2019-04-04
Add 3 Years : 2022-07-04
Minus 3 Years : 2016-07-04

Build a date

import java.time.LocalDate; //for LocalDate
public class MyDate{
    public static void main(String[] args){
      byte day = 12;
      byte month = 2;
      short year =2020;
      LocalDate date = LocalDate.of(year, month, day);
      System.out.println(date);
    }
}

2020-02-12

Convert Second to other format

import java.time.Duration; 
public class MyDate{
    public static void main(String[] args){
      int second = 5000;
      Duration time = Duration.ofSeconds(second);

      System.out.println(time);
      System.out.println("Minutes : "+time.toMinutes());
      System.out.println("Day : "+time.toDays());
      System.out.println("Millisecond : "+time.toMillis());
      System.out.println("Nanosecond : "+time.toNanos());
  }
}

PT1H23M20S
Minutes : 83
Day : 0
Millisecond : 5000000
Nanosecond : 5000000000000

Convert string text to date object

//Java string to date conversion
import java.util.Date;
import java.text.SimpleDateFormat;  
import java.util.Locale; 
import java.text.DateFormat; 
class Execution{
  public int data;
  public static void main(String[] args) {
    //date string text
    String text = "January 26 2020";
    //set pattern according to date text (January 26 2020=MMMM d yyyy)  
    DateFormat format = new SimpleDateFormat("MMMM d yyyy", Locale.ENGLISH);

    try {
     Date myDate = format.parse(text);
     System.out.println(myDate); 
   }
   catch (Exception e) {
     System.out.println(e); 
   }

 }
}

Output

Sun Jan 26 00:00:00 IST 2020

Get interval of two dates

//Java compare two dates difference (intervals)
import java.util.Date;
import java.util.concurrent.TimeUnit;
import java.text.SimpleDateFormat;  
import java.util.Locale; 
import java.text.DateFormat; 
class Execution{
  public static long getDifference(Date d1,Date d2,TimeUnit unit){
    //get d
    long milliSeconds = d1.getTime() - d2.getTime();
    return unit.convert(milliSeconds,TimeUnit.MILLISECONDS);

  }
  public static void main(String[] args) {
    //date string text
    String text1 = "January 26 2019 6:15:19";
    String text2 = "August  15 2019 7:18:59";
    String pattern="MMMM d yyyy HH:mm:ss"; //according to text date
    DateFormat format = new SimpleDateFormat(pattern, Locale.ENGLISH);

    try {
     Date date1 = format.parse(text1);
     Date date2 = format.parse(text2);
     
     long difference=getDifference(date2,date1,TimeUnit.MINUTES);
     long minutes=difference %(60*24); //in case check minutes
     long hours=minutes/60;
     minutes%=60;
     difference/=60*24;
     System.out.println("Days "+difference+" hours :"+ hours +" minutes :"+minutes);
   }

   catch (Exception e) {
     System.out.println(e); 
   }

 }
}

Output

Days 201 hours :1 minutes :3

Change date format in a Java string

//Change date format in a Java string
import java.util.Date;
import java.text.SimpleDateFormat;  
import java.util.Locale; 
import java.text.DateFormat; 
class Execution{
  public static void main(String[] args) {
    //date string text
    String text = "January 12 2020";
    //set pattern according to date text (January 26 2020=MMMM d yyyy)  
    DateFormat pattern = new SimpleDateFormat("MMMM d yyyy", Locale.ENGLISH);

    try {
     Date myDate = pattern.parse(text);
     //modified date format 
     String formatted = new SimpleDateFormat("yyyy-MM-dd").format(myDate);
     System.out.println(myDate);
     System.out.println(formatted); 
   }
   catch (Exception e) {
     System.out.println(e); 
   }

 }
}

Output

Sun Jan 12 00:00:00 IST 2020
2020-01-12