FormatDate.java

package com.levelup.java.date.format;

import static org.junit.Assert.assertEquals;

import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.Month;
import java.util.Calendar;
import java.util.TimeZone;

import org.apache.commons.lang3.time.DateFormatUtils;
import org.joda.time.DateTime;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;
import org.junit.Ignore;
import org.junit.Test;

/**
 * This java example will demonstrate formatting a date of January 15, 1967.
 * 
 * @author Justin Musgrove
 * @see <a href='http://www.leveluplunch.com/java/examples/format-date/'>Format date</a>
 * 
 */
public class FormatDate {
	
	@Test
	public void format_date_in_java () {
		
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.MONTH, Calendar.JANUARY);
		cal.set(Calendar.DAY_OF_MONTH, 15);
		cal.set(Calendar.YEAR, 1967);

		SimpleDateFormat dateFormatter = new SimpleDateFormat("MM/dd/yyyy");
		String dateFirstSuperBowlWasPlayed = dateFormatter.format(cal.getTime());
		
		assertEquals("01/15/1967", dateFirstSuperBowlWasPlayed);
	}
	
	@Test
	@Ignore("Build fails due to timezone discrepancy")
	public void format_date_in_java_using_string_format() {

		Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("GMT-0600"));
		cal.set(Calendar.MONTH, Calendar.JANUARY);
		cal.set(Calendar.DAY_OF_MONTH, 15);
		cal.set(Calendar.YEAR, 1967);
		cal.set(Calendar.HOUR, 0);
		cal.set(Calendar.SECOND, 0);
		cal.set(Calendar.MINUTE, 0);
		cal.set(Calendar.MILLISECOND, 0);

		String str = String.format("Current Date/Time : %tc", cal.getTime());
		
		assertEquals("Current Date/Time : Sun Jan 15 12:00:00 CST 1967", str);
	}

	@Test
	public void format_date_in_java8 () {
		
		java.time.format.DateTimeFormatter formatter = 
				 java.time.format.DateTimeFormatter.ofPattern("MM/dd/yyyy");
		 
		LocalDate localDate = LocalDate.of(1967, Month.JANUARY, 15);
		
		String dateFirstSuperBowlWasPlayed = localDate.format(formatter);
		
		assertEquals("01/15/1967", dateFirstSuperBowlWasPlayed);
	}
	
	@Test
	public void format_date_in_java_with_joda () {
		
		DateTime dateFirstSuperBowlWasPlayed = new DateTime(1967, 1, 15, 0, 0);

		DateTimeFormatter fmt = DateTimeFormat.forPattern("MM/dd/yyyy");
		
		assertEquals("01/15/1967", dateFirstSuperBowlWasPlayed.toString(fmt));
	}
	
	@Test
	public void format_date_in_java_with_apachecommons () {
		Calendar cal = Calendar.getInstance();
		cal.set(Calendar.MONTH, Calendar.JANUARY);
		cal.set(Calendar.DAY_OF_MONTH, 15);
		cal.set(Calendar.YEAR, 1967);

		String dateFirstSuperBowlWasPlayed = DateFormatUtils.format(cal, "MM/dd/yyyy");
		assertEquals("01/15/1967", dateFirstSuperBowlWasPlayed);
	}

}