Date manipulation in Java

How to determine the day of the week by passing a specific date?

1). Using calendar Class


Calendar c = Calendar.getInstance();
c.setTime(yourDate);
int dayOfWeek = c.get(Calendar.DAY_OF_WEEK);

2). Using SimpleDateFormat


String input_date="14/07/2020";
  SimpleDateFormat format1=new SimpleDateFormat("dd/MM/yyyy");
  Date dt1=format1.parse(input_date);
  DateFormat format2=new SimpleDateFormat("EEEE"); 
  String finalDay=format2.format(dt1);

3). Using DateTimeFormatter


int dayOfWeek = localDate.getDayOfWeek(); // Follows ISO 8601 standard, where Monday = 1, Sunday = 7.
Locale locale = Locale.US;  // Locale specifies the human language to use in determining day-of-week name (Tuesday in English versus Mardi in French).
DateTimeFormatter formatterOutput = DateTimeFormat.forPattern( "E" ).withLocale( locale );
String output = formatterOutput.print( localDate ); // 'E' is code for abbreviation of day-of-week name. See Joda-Time doc.
String outputQuébécois = formatterOutput.withLocale( Locale.CANADA_FRENCH ).print( localDate );
System.out.println( "input: " + input );
System.out.println( "localDate: " + localDate ); // Defaults to ISO 8601 formatted strings.
System.out.println( "dayOfWeek: " + dayOfWee

Get year, month and day from a given Date using Using Java 7

1). Using java util package and classes like Date and Calendar we can get a year, month, and day from a given date.

We create a date and Calendar Instance here


Date date =  new Date();
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);

Get year in integer

We need to pass Calendar.YEAR to the calender.get Method.


int year = calendar.get(Calendar.YEAR);

Get month in integer

We need to pass Calendar.MONTH to calender.get Method.


int month = calendar.get(Calendar.MONTH);

Get day in integer

We need to pass Calendar.DAY_OF_MONTH to the calender.get Method.


int day = calendar.get(Calendar.DAY_OF_MONTH);


package com.javacodestuffs.core.datetime;
import java.util.Calendar;
import java.util.Date;
import java.time.LocalDate;
import java.text.SimpleDateFormat;

public class LocalDateExample1 {
	public static void main(String[] args) {

		Date date = new Date();
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);

		int year = calendar.get(Calendar.YEAR);
		int month = calendar.get(Calendar.MONTH);
		int day = calendar.get(Calendar.DAY_OF_MONTH);

		System.out.println("year : " + year);
		System.out.println("month : " + month);
		System.out.println("day : " + day);
	}
}

output:
year : 2020
month : 6
day : 14

Using Java 8 to get Date details

Using Java 8 makes our life easier while manipulating DateTime.

The java.time package contains a number of classes that are used for manipulation of Date.

Java LocalDate class is an immutable class that represents the Date with a default format of yyyy-MM-dd. It inherits Object class and implements the ChronoLocalDate interface.


LocalDate date = LocalDate.now();

1). Get Year

localDate.getYear();

2). Get Month

localDate.getMonthValue();

3). Get Day

localDate.getDayOfMonth();

Here is the complete program


package com.javacodestuffs.core.datetime;
import java.util.*;
import java.time.LocalDate;
import java.text.SimpleDateFormat;

public class LocalDateExample2 {
	public static void main(String[] args) {

		LocalDate localDate = LocalDate.now();

		int year = localDate.getYear();
		int month = localDate.getMonthValue();
		int day = localDate.getDayOfMonth();

		System.out.println("year: " + year);
		System.out.println("month: " + month);
		System.out.println("day: " + day);
	}
}
output:
year: 2020
month: 7
day: 14

Get DayOfWeek using the switch


package com.javacodestuffs.core.datetime;
import java.util.*;

public class DayOfWeek {

	public static void main(String[] args) {

		Calendar cal = Calendar.getInstance();
		int day = cal.get(Calendar.DAY_OF_WEEK);

		System.out.print("Today is : ");
		switch (day) {
		case 1:
			System.out.print("Sunday");
			break;
		case 2:
			System.out.print("Monday");
			break;
		case 3:
			System.out.print("Tuesday");
			break;
		case 4:
			System.out.print("Wednesday");
			break;
		case 5:
			System.out.print("Thursday");
			break;
		case 6:
			System.out.print("Friday");
			break;
		case 7:
			System.out.print("Saturday");
		}

	}
}

output:
Today is : Tuesday

Java SimpleDateFormat to get date in ("yyyy-MM-dd'T'HH:mm:ss'Z'") format


SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));//UTC

String currentDate1 = sdf22.format(date1);


package com.javacodestuffs.core.datetime;
import java.util.* ;
import java.time.LocalDate;
import java.text.SimpleDateFormat;
public class DateInUTCFomat {

	public static void main(String[] args) {

		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
		sdf.setTimeZone(TimeZone.getTimeZone("GMT")); //UTC
		LocalDate date = LocalDate.now();

		System.out.println("The Date in UTC format is : "+sdf.format(new Date()));

	}
}
output:
The Date in UTC format is : 2020-07-14T19:08:27Z

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In this article, we have seen the Date manipulation in Java with examples. All source code in the article can be found in the GitHub repository.

Javacodestuffs

Date manipulation in Java