DateUtility class for converting String into Date and Vice Versa using Java

In this post, we will see how to convert String into Date and vice versa.

DateUtility.java

package com.ranga.utility;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Objects;
import java.util.TimeZone;

/*
*  Utility class for converting string into date.
*  @author Ranga Reddy
*  @version 1.0
*  @since 08/Jan/2017
*/
public class DateUtility {

    /**
     * Used to get the date in Date format.
     * @param dateInString - date in string format
     * @param format - format to get the date.
     * @return date parsed from the string.
     * @throws ParseException
     */
    public static Date parseDate(String dateInString, String format) throws ParseException {
        Objects.requireNonNull(dateInString, "Date string value must not be null.");
        Objects.requireNonNull(format, "Format must not be null.");
        DateFormat dateFormat = new SimpleDateFormat(format);
        return dateFormat.parse(dateInString);
    }

    /**
     * Used to get the date in String format.
     * @param date - the date
     * @param pattern - the pattern
     * @return the date in String.
     */
    public static String format(Date date, String pattern) {
        return format(date, pattern, null);
    }

    /**
     * Used to get the date in String format.
     * @param date - the date
     * @param pattern - the pattern
     * @param timeZone - the timeZone
     * @return
     */
    public static String format(Date date, String pattern, TimeZone timeZone) {
        Objects.requireNonNull(date, "Date must not be null.");
        Objects.requireNonNull(pattern, "Pattern must not be null.");
        DateFormat formatter = new SimpleDateFormat(pattern);
        if (timeZone != null) {
            formatter.setTimeZone(timeZone);
        }
        return formatter.format(date);
    }

    /**
     * Used to convert the date in one format to another format.
     * @param fromDate - the from date
     * @param fromPattern - the from pattern
     * @param toPattern - the to pattern
     * @return formated date
     * @throws ParseException
     */
    public static String convertDateFromOneFormatToAnother(String fromDate, String fromPattern, String toPattern)
            throws ParseException {
        Objects.requireNonNull(fromDate, "From Date must not be null.");
        Objects.requireNonNull(fromPattern, "From Pattern must not be null.");
        Objects.requireNonNull(toPattern, "To Pattern must not be null.");
        
        DateFormat fromDateFormat = new SimpleDateFormat(fromPattern);
        Date sourceDate = fromDateFormat.parse(fromDate);
        DateFormat toDateFormat = new SimpleDateFormat(toPattern);
        return toDateFormat.format(sourceDate);
    }


    /**
     * Used to validate the date.
     * 
     * @param date - date in string.
     * @param format - format to check the date
     * @return true if date is valid otherwise return false.
     */
    public static boolean isValidDate(String date, String pattern) {
        Objects.requireNonNull(date, "Date must not be null.");
        Objects.requireNonNull(pattern, "Pattern must not be null.");

        DateFormat dateFormat = new SimpleDateFormat(pattern);
        try {
            dateFormat.parse(date);
            return true;
        } catch (Exception e) {
            System.err.println("Encountered exception while validating the date. " + e);
            return false;
        }
    }
}

DateUtilityTest.java

package com.ranga.utility;

import java.text.ParseException;
import java.util.Date;

/**
 * Used to test the DateUtility functionalities.
 * 
 * @author Ranga Reddy
 * @version 1.0
 * @since 08/Jan/2017
 */
public class DateUtilityTest {
    public static void main(String[] args) throws ParseException {
        
        Date date = new Date();
        String formatedDate = DateUtility.format(date, "yyyy-MMM-dd HH:mm:ss a");
        System.out.println("Formatted date: "+formatedDate);
        
        String parseDateString = "01-Jul-1988";
        Date convertedDate = DateUtility.parseDate(parseDateString, "dd-MMM-yyyy");
        System.out.println("Converted date: "+convertedDate);
        
        boolean isValidDate = DateUtility.isValidDate(formatedDate, "yyyy-MMM-dd");
        System.out.println("IsValid date: "+isValidDate);
    }
}

Output:

Formatted date: 2017-Jan-08 19:13:32 PM
Converted date: Fri Jul 01 00:00:00 IST 1988
IsValid date: true

Happy Learning ...!