How to convert given Date to Calendar in Java?

Problem Description :

Write a program in Java that converts given Date to Calendar.

Date to Calendar conversion

Concept :

By default Calendar represent current date, for converting given date to Calendar we have to use setTime(Date date) method of Calendar class that is present in java.util.* package.

Recommended :

How to check whether given date is valid or not ?

How to convert Calendar to Date?

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 convert Date to Calendar?
	*
	*/
	public class ConvertDateToCalendar {
	/*
	* For converting Date to Calendar we have to use setTime() method of
	* Calendar class.
	*/
	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) {
	System.out.println("My date : " + mydate);
	/*
	* Creating Calendar class instance By default it returns
	* current date.
	*/
	Calendar calendar = Calendar.getInstance();
	// Converting Date to Calendar.
	calendar.setTime(mydate);
	// Converting Calendar to Date.
	Date calendarDate = calendar.getTime();
	System.out.println("Calendar date : " + calendarDate);
	} 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 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 ConvertDateToCalendar.java hosted with ❤ by GitHub

Output :

Output - How to convert given Date to Calendar 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#setTime(java.util.Date)

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, Conversion problems, Date to Calendar in Java, String, Solution in Java, DateFormat, SimpleDateFormat, Regular expressions, if else statement.

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