Date Formatting In Java With Time Zone

This tutorial will help you getting the current time, date and day in any given format for any particular time zone in java.
Listed below are some IDs for some common Time zones in the US:

Time Zone	Java Time Zone ID
Hawaiian Standard Time	US/Hawaii
Alaska Standard Time	US/Alaska
Pacific Standard Time	US/Pacific
Mountain Standard Time	US/Mountain
Central Standard Time	US/Central
Eastern Standard Time	US/Eastern

Java 6 makes available 575 different time zone IDs for places around the world.  It is recommended that Java Time zone IDs mentioned in the above table are used, instead of using three letter time zone abbreviations like “EST”, “PDT”, etc.  as they are not unique in their usage around the world.

For Example, CST can stand for both Central Standard Time and China Standard Time.

Though Java can still recognise these for compatibility with Java 1.1, Usage of these abbreviations in JREs may produce unpredictable results. Currently Java uses the “tz database” for listing of time zone related to a particular location.

Sample Code for obtaining the list of Time Zones in the US:

For the purpose of learning, “US/Eastern” has been used in the code in the below example.The functions used in the below complete code, takes in the values of the date format and the time zone. The user needs to decide the format in which the date/day/time value is required and the target time zone. For date formatting you can refer Date formatting in java.

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

public class ObtainDate
{
   public static void main(String[] args)
   {
      ObtainDate obtainDate = new ObtainDate();
      TimeZone timeZone = TimeZone.getTimeZone("US/Eastern");
      String dateFormat = "MMMM dd,yyyy G"; //MMMM dd,yyyy G
      String timeFormat = "hh:mm:ss.SSS a zzzz";
      String dayFormat = "EEEEEE";
      System.out.println("Todays Day:" + obtainDate.getTodaysDay(dayFormat,timeZone));
      System.out.println("Todays Date:" + obtainDate.getTodayDate(dateFormat,timeZone));
      System.out.println("Current Time:" + obtainDate.getCurrentTime(timeFormat,timeZone));
  }

  /**
   * Description - Method to Get Today's day
   * @author Chaitanya
   * @param dateFormat
   * @param TimeZone
   */
  public String getTodaysDay(String dayFormat, TimeZone timeZone)
  {
      Date date = new Date();
      /* Specifying the format */
      DateFormat requiredFormat = new SimpleDateFormat(dayFormat);
      /* Setting the Timezone */
      requiredFormat.setTimeZone(timeZone);
      /* Picking the day value in the required Format */
      String strCurrentDay = requiredFormat.format(date).toUpperCase();
      return strCurrentDay;
   }

   /**
    * Description - Method to Get Current time
    * @author Chaitanya
    * @param dateFormat
    * @param TimeZone
    */
   public String getCurrentTime(String timeFormat, TimeZone timeZone)
   {
      /* Specifying the format */ 
      DateFormat dateFormat = new SimpleDateFormat(timeFormat);
      /* Setting the Timezone */
      Calendar cal = Calendar.getInstance(timeZone);
      dateFormat.setTimeZone(cal.getTimeZone());
      /* Picking the time value in the required Format */
      String currentTime = dateFormat.format(cal.getTime());
      return currentTime;
   }

   /**
    * Description - Method to Get Today's date
    * @author Chaitanya
    * @param dateFormat
    * @param TimeZone
    */
   public String getTodayDate(String dateFormat, TimeZone timeZone)
   {
       Date todayDate = new Date();
       /* Specifying the format */
       DateFormat todayDateFormat = new SimpleDateFormat(dateFormat);
       /* Setting the Timezone */
       todayDateFormat.setTimeZone(timeZone);
       /* Picking the date value in the required Format */
       String strTodayDate = todayDateFormat.format(todayDate);
       return strTodayDate;
   }
}

Output:

Todays Day:THURSDAY
Todays Date:October 19,2017 AD
Current Time:12:15:44.232 PM Eastern Daylight Time

Steps involved:
The basic steps in the calculation of day/date/time in a particular time zone:

• Obtain a new Date object
• A date format object is created in Simple Date Format
• The required format is assigned to the date format object – For Eg: hh:mm:ss.SSS
• Set the required time zone to the date format object
• Pick the day/date/time value from the date format object by passing the date object created in the first step.

The following table provides the various date patterns and their significance in Java Timestamp Format:

Pattern	Denotes
yyyy	Current Year
MM	Current Month in number
MMM	Current Month abbreviated
MMMM	Current Month in Full
dd	Current Date of the month
DD	Current Day of the year
hh	Current Time’s Hour (12 Hour clock)
HH	Current Time’s Hour (24 Hour clock)
a	AM/PM
mm	Current Time’s Minute
ss	Current Time’s Second
SSS	Current Time’s Millisecond (the number of SSS can be incremented to obtain the fraction of the second)
G	Epoch
zzz	Time Zone abbreviated
zzzz	Time Zone in Full
EEEEEE	Current Day in Full
EEE	Current Day abbreviated

A reference like yyyy.MM.dd G hh:mm:ss would yield an output like 2011.11.07 AD 1:11:57 PM. At the same time yyyy.MMM.DD  G HH:mm.SSS would yield output of 2011.JUL.194 AD 23:11.938.

References:

• TimeStamp – JavaDoc
• DateConvert – JavaDoc
• TimeZones – wikipedia

Related Posts:

1. Java – DateFormat examples
2. Java – Validating Date Format
3. Java – Add Days to current Date
4. Java – Date Comparison
5. Java – Parse Date