As different countries do opt for different formats. So here the goal is simply to print dates of calendar in different years. The generic symbolic notation opted across the globe is:
| Symbolic Notation | Depicts |
|---|---|
| y | year |
| M | month in year |
| d | day in month |
| E | day of week |
Concept: Whenever it comes down to the date and time the primary goal is to Date Class. It is necessary to be imported into our program.
Date Class was introduced in java in JDK version 1.0 but was later improved in JDK 1.1 by introducing Calendar Class. It deprecated most Calendar Class as 4 out of 6 constructors are marked as deprecated and most of the methods inside it. These two JDK are outdated now and hence known as legacy API. Finally, in 2014 in JDK8 new date/Time API was introduced. it includes java.time package which is now the main API for a date, time, instants, and duration.
| Class | Description |
|---|---|
| Clock | A clock providing access t the current instant, date, and time using a time zone |
| Duration | A time-based amount of time, such as ‘34.5 seconds’ |
| Instant | An instantaneous point on the time-line |
| LocalDate | A date without a time zine, calendar year such as 2007-12-03 |
| LocalTime | A time without a time zone in the calendar system |
| MonthDay | A month day in the calendar system |
| OffsetTime | A time with an offset from Greenwich in the calendar system |
| Period | A data-based amount of time in the calendar system |
| Year | A year in the calendar system |
| ZonedDateTime | A date with a time zone in a calendar system |
| ZoneOffset | A time zone offset from Greenwich |
Package java.time.in JDK 8
There are different ways in which we can obtain the current date and time in java. Java doesn’t have a built-in Date class, though we can import java.time package to work with the time and date API. Some classes are as below:
- java.time.LocalDate– represents a date (year, month, day (yyyy-MM-dd)).
- java.time.LocalDateTime– represents both a date and a time (yyyy-MM-dd-HH-mm-ss-ns).
- java.time.format.DateTimeFormatter– formatter for displaying and parsing date-time objects.
When there is a need to display date and time in a different format, the ofPattern() method is used to accept all sorts of values. There are numerous formats that can be invoked later on can be mixed and match letters to achieve the required pattern.
Here the dealing will be with 3 types of formats:
- yyyy-MM-dd
- DD/MM/YY
- dd MMM yyyy
Below are the java programs for different date format.
Format 1: yyyy-MM-dd
Java
// Java Program to Display Dates in Different Format// Importing Classes/Filesimport java.io.*;// Importing speccificaly Time Class and functionalitiesimport java.time.*;class GFG { // Main driver method public static void main(String[] args) { // Create an object of LoacalDate type LocalDate date = LocalDate.now(); // .now() method to tore the current date // Print current date System.out.println(date); }} |
Output:
2020-11-03
Format 2: DD/MM/YY
Java
// Java Program to Display Dates in Different Format// Importing generic Classes/Filesimport java.io.*;// Importing specific Date and Time Classes/Filesimport java.time.*;import java.time.format.DateTimeFormatter;class GFG { // Main driver method public static void main(String[] args) { // Create date time object and store current time in // default format yy-mm-dd LocalDateTime date = LocalDateTime.now(); // Creating DateTimeFormatter object // to specify date format DateTimeFormatter myDateFormat = DateTimeFormatter.ofPattern("dd/MM/yyyy"); // Change date into your format and store it in // string object String formattedDate = date.format(myDateFormat); // Print formatted date System.out.println(formattedDate); }} |
Output:
03/11/2020
Format 3: Day, dd MMM yyyy
Java
// Java Program to Display Dates in Different Format// Importing generic Classes/Filesimport java.io.*;// Importing Date and time specific Classesimport java.time.*;import java.time.format.DateTimeFormatter;class GFG { // Main driver method public static void main(String[] args) { // Create date time object and store current time in // default format yy-mm-dd LocalDateTime date = LocalDateTime.now(); // Specify the date format // Note: more than 3 characters result in full name DateTimeFormatter myDateFormat = DateTimeFormatter.ofPattern( "EEEE, dd MMM yyyy"); // e.g- MMM = Oct and MMMM = October // Change date into req format and store it in // string object String formattedDate = date.format(myDateFormat); // Printing formatted date System.out.println(formattedDate); }} |
Output:
Tuesday, 03 Nov 2020
