A guide to how to use DateTimeFormatter to convert java 8 date's into string form in predefined and custom date patterns.
1. Overview
In this tutorial, you'll learn how to use DateTimeFormatter class to convert date to string in java 8.
As you know, DateTimeFormatter is also a final, an immutable and thread safe class.
What we'll learn here is
What are the predefined date formats in DateTimeFormatter class?
How to use custom or user defined date patterns for date parsing to string?
How to use DateTimeFormatter class with FormatStyle enum?
How to convert LocalDateTime to String?
How to convert LocalDate to String?
How to convert LocalTime to String?
How to convert ZonedDateTime to String?
2. DateTimeFormatter Supported Predefined and Custom Formats
Below are the examples how to get the builtin and create custom formats. Use DateTimeFormatter.ofPattern(String) method to define our own date pattern and it takes the string argument to store the custom pattern.
package com.javaprogramto.java8.dates.datetimeformatter;
import java.time.format.DateTimeFormatter;
public class DateTimeFormatterExample {
public static void main(String[] args) {
// Predefined formats
DateTimeFormatter predefinedFormat1 = DateTimeFormatter.BASIC_ISO_DATE;
DateTimeFormatter predefinedFormat2 = DateTimeFormatter.ISO_DATE;
DateTimeFormatter predefinedFormat3 = DateTimeFormatter.ISO_ZONED_DATE_TIME;
// Custom formats
DateTimeFormatter customFormat1 = DateTimeFormatter.ofPattern("yyyy-MMM");
DateTimeFormatter customFormat2 = DateTimeFormatter.ofPattern("yyyy-MM-dd 'at' hh:mm a");
DateTimeFormatter customFormat3 = DateTimeFormatter.ofPattern("yyyy-MM-dd z");
}
}
3. DateTimeFormatter With FormatStyle Enum
As always builtin formats does not enough to fulfil the human readable formats.
FormatStyle enum is defined withe 4 predefined formats FULL, LONG, MEDIUM and SHORT forms.
Step 1:
Get the right FormatStyle format.
Step 2:
Call DateTimeFormatter.ofLocalizedDate() and pass the FormatStyle to it as argument.
Step 3:
Create the LocalDateTime object using now() method and next call format() method on LocalDateTime instance by passing the formatter from the step 2.
package com.javaprogramto.java8.dates.datetimeformatter;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;
public class DateTimeFormatterFormatStyleExample {
public static void main(String[] args) {
FormatStyle full = FormatStyle.FULL;
DateTimeFormatter formatter = DateTimeFormatter.ofLocalizedDate(full);
LocalDateTime datetime = LocalDateTime.now();
String fullForm = datetime.format(formatter);
System.out.println("Full date form in string : "+fullForm);
}
}
Output:
Full date form in string : Thursday, November 26, 2020
4. DateTimeFormatter - Convert LocalDateTime to String
Next, Convert java 8 LocalDateTime to String format using DateTimeFormatter class in simple steps.
Step 1:
Create a custom date formatter using DateTimeFormatter.ofPattern() and pass the pattern to this method as "yyyy-MM-dd 'at' hh:mm a". Store the result into format variable.
Step 2:
Get the current date and time using LocalDateTime.now() and store the result in the datetime variable.
Step 3:
Finally, call datetime.format(formatter) method which returns the string which holds the date time value in our own format.
package com.javaprogramto.java8.dates.datetimeformatter;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
public class DateTimeFormatterLocalDateTimeToStringExample {
public static void main(String[] args) {
// Creating a custom formatter
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd 'at' hh:mm a");
// Getting current date time using LocalDateTime.now() method
LocalDateTime datetime = LocalDateTime.now();
// converting date to string
String fullForm = datetime.format(formatter);
// printing date string form
System.out.println("LocalDateTime form in string : " + fullForm);
}
}
Output:
LocalDateTime form in string : 2020-11-26 at 08:55 PM
5. DateTimeFormatter - Convert LocalDate to String
Next, Convert java 8 LocalDate to String format using DateTimeFormatter class in simple steps.
Step 1:
Create a custom date formatter using DateTimeFormatter.ofPattern() and pass the pattern as "yyyy-MMM" to this method. Store the result into format variable.
Step 2:
Get the current date and time using LocalDate.now() and store the result in the datetime variable.
Step 3:
Finally, call datetime.format(formatter) method which returns the string which holds the date time value in our own format.
package com.javaprogramto.java8.dates.datetimeformatter;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
public class DateTimeFormatterLocalDateToStringExample {
public static void main(String[] args) {
// Creating a custom formatter
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MMM");
// Getting current date time using LocalDate.now() method
LocalDate datetime = LocalDate.now();
// converting date to string
String fullForm = datetime.format(formatter);
// printing date string form
System.out.println("LocalDate form in string : " + fullForm);
}
}
Output:
LocalDate form in string : 2020-Nov
6. DateTimeFormatter - Convert LocalTime to String
Next, Convert java 8 LocalTime to String format "hh:ss a" using DateTimeFormatter class in simple steps.
Step 1:
Create a custom date formatter using DateTimeFormatter.ofPattern() and pass the pattern as "hh:ss a" to this method. Store the result into format variable.
Step 2:
Get the current date and time using LocalTime.now() and store the result in the datetime variable.
Step 3:
Finally, call datetime.format(formatter) method which returns the string which holds the date time value in our own format.
package com.javaprogramto.java8.dates.datetimeformatter;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
public class DateTimeFormatterLocalTimeToStringExample {
public static void main(String[] args) {
// Creating a custom formatter
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("hh:ss a");
// Getting current date time using LocalTime.now() method
LocalTime datetime = LocalTime.now();
// converting date to string
String fullForm = datetime.format(formatter);
// printing date string form
System.out.println("LocalTime form in string : " + fullForm);
}
}
Output:
LocalTime form in string : 09:03 PM
7. DateTimeFormatter - Convert ZonedDateTime to String
As steps as above but it converts ZonedDateTime to string format.
package com.javaprogramto.java8.dates.datetimeformatter;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
public class DateTimeFormatterZonedDateTimeToStringExample {
public static void main(String[] args) {
// Creating a custom formatter
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMM/dd/yyyy 'at' hh:mm a z");
// Getting current date time using ZonedDateTime.now() method
ZonedDateTime datetime = ZonedDateTime.now();
// converting date to string
String fullForm = datetime.format(formatter);
// printing date string form
System.out.println("ZonedDateTime form in string : " + fullForm);
}
}
Output:
ZonedDateTime form in string : Nov/26/2020 at 09:08 PM IST
8. Conclusion
In this article, We've seen how to use the DateTimeFormatter with different Java 8 DateTime API classes to convert them into String format.
Read Next
COMMENTS