How to get day name of given date in Java?

Problem Description :

Write a program in Java that prints day name of given date.

Print day name in Java

Concept :

We are using below method of Calendar class that is present in java.util.* package.

public int get(int field) -> In this method we have to pass Calendar class constant DAY_OF_WEEK and finally this method returns one value from 1-7. After that using switch case we are printing day name.

Recommended :

How to check whether given date is valid or not ?

How to convert Date to Calendar ?

Java Program :

	package com.javamultiplex.datetime;
	import java.text.DateFormat;
	import java.text.ParseException;
	import java.text.SimpleDateFormat;
	import java.util.Calendar;
	import java.util.Date;
	import java.util.Scanner;
	/**
	*
	* @author Rohit Agarwal
	* @category Date and Time
	* @problem How to get day name of given date?
	*
	*/
	public class GetWeekDayName {
	public static void main(String[] args) {
	Scanner input = null;
	try {
	input = new Scanner(System.in);
	System.out.println("Enter date in dd/MM/yyyy format :");
	String date = input.next();
	// If Date is valid, converting String to Date
	Date mydate = getValidDate(date);
	if (mydate != null) {
	// Creating Calendar class instance.
	Calendar calendar = Calendar.getInstance();
	// Converting Date to Calendar.
	calendar.setTime(mydate);
	int dayofWeek = calendar.get(Calendar.DAY_OF_WEEK);
	String dayName = getDayName(dayofWeek);
	System.out.println("Day : " + dayName);
	} else {
	System.out.println("Date is invalid.");
	}
	} finally {
	if (input != null) {
	input.close();
	}
	}
	}
	private static Date getValidDate(String date) {
	Date mydate = null;
	if (isValidDateFormat(date)) {
	/*
	* d -> Day of month
	* M -> Month of year
	* y -> Year
	*/
	DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy");
	/*
	* By default setLenient() is true. We should make it false for
	* strict date validations.
	*
	* If setLenient() is true - It accepts all dates. If setLenient()
	* is false - It accepts only valid dates.
	*/
	dateFormat.setLenient(false);
	try {
	mydate = dateFormat.parse(date);
	} catch (ParseException e) {
	mydate = null;
	}
	}
	return mydate;
	}
	private static String getDayName(int dayofWeek) {
	String dayName = null;
	switch (dayofWeek) {
	case 1:
	dayName = "Sunday";
	break;
	case 2:
	dayName = "Monday";
	break;
	case 3:
	dayName = "Tuesday";
	break;
	case 4:
	dayName = "Wednesday";
	break;
	case 5:
	dayName = "Thursday";
	break;
	case 6:
	dayName = "Friday";
	break;
	case 7:
	dayName = "Saturday";
	break;
	}
	return dayName;
	}
	private static boolean isValidDateFormat(String date) {
	/*
	* Regular Expression that matches String with format dd/MM/yyyy.
	* dd -> 01-31
	* MM -> 01-12
	* yyyy -> 4 digit number
	*/
	String pattern = "(0?[1-9]|[12][0-9]|3[01])\\/(0?[1-9]|1[0-2])\\/([0-9]{4})";
	boolean result = false;
	if (date.matches(pattern)) {
	result = true;
	}
	return result;
	}
	}

view raw GetWeekDayName.java hosted with ❤ by GitHub

Output :

Output - How to print day name of given date in Java?

References :

https://docs.oracle.com/javase/7/docs/api/java/util/Calendar.html

https://docs.oracle.com/javase/7/docs/api/java/util/Calendar.html#get(int)

https://docs.oracle.com/javase/7/docs/api/java/util/Calendar.html#DAY_OF_WEEK

Thank you friends, I hope you have clearly understood the solution of this problem. If you have any doubt, suggestion or query please feel free to comment below. You can also discuss this solution in our forum.

Tags : Date and Time problems, Get day name, Solution in Java,  String, Regular expressions, DateFormat, SimpleDateFormat, if else statement, switch statement, Calendar.

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