In this post, I will guide you how to convert String to Date and format Date to String in Java.

It’s a very common case in which one has a need to create a Date object from a given String in a specified date pattern, for example:

String strDate = “25/03/1990”;

Here, the strDate string is in the format “dd/MM/yyyy” which is needed to be parsed to create a new Date object with the exact components (day, month and year). This is referred as date parsing.

One also needs to display a Date object as a String in a specified date pattern. This is referred as date formatting.

In Java, we can accomplish that by using the following two classes in the java.text package:

• DateFormat: an abstract class for date/time formatting.
• SimpleDateFormat: a concrete sub class of the DateFormat class. It implements the parsing and formatting dates in a locale-sensitive manner.

For example, the following code snippet tries to parse a String to a Date object with the date pattern “dd/MM/yyyy”:

String pattern = "dd/MM/yyyy";
DateFormat dateFormat = new SimpleDateFormat(pattern);

String strDate = "25/03/1990";

try {
	Date parsedDate = dateFormat.parse(strDate);
	System.out.println("The parsed date is: " + parsedDate);
} catch (ParseException e) {
	e.printStackTrace();
}

Output:

The parsed date is: Sun Mar 25 00:00:00 ICT 1990

And the following code tries to format a Date object as a String in the pattern “dd/MM/yyyy”:

String pattern = "dd/MM/yyyy";
DateFormat dateFormat = new SimpleDateFormat(pattern);

Date newDate = new Date();
String formattedDate = dateFormat.format(newDate);
System.out.println("The formatted date is: " + formattedDate);

Output:

The formatted date is: 26/03/2014

The above examples parse and format dates according to a fixed pattern. In case you want to parse and format dates according to user’s default locale or a specific locale, the following SimpleDateFormat’s factory methods would help:

• DateFormat.getDateInstance(): returns a date formatter with the default formatting style for the current locale.
• DateFormat.getDateInstance(int style, Locale aLocale): returns a date formatter with the given formatting style and the given locale.

Here’s an example of date formatting and parsing for the default locale:

DateFormat dateFormater = DateFormat.getInstance();
String formattedDate = dateFormater.format(new Date());
System.out.println("The formatted date is: " + formattedDate);

try {
	Date parsedDate = dateFormater.parse("3/31/14 12:00 AM");
	System.out.println("The parsed date is: " + parsedDate);
} catch (ParseException ex) {
	ex.printStackTrace();
}

Output:

The formatted date is: 3/27/14 11:43 AM
The parsed date is: Mon Mar 31 00:00:00 ICT 2014

Here’s an example of date formatting and parsing for French locale:

DateFormat dateFormatter = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.FRANCE);
String formattedDate = dateFormatter.format(new Date());
System.out.println("The formatted date is: " + formattedDate);

try {
	Date parsedDate = dateFormatter.parse("01 avril 2014");
	System.out.println("The parsed date is: " + parsedDate);
} catch (ParseException ex) {
	ex.printStackTrace();
}

Output:

The formatted date is: 27 mars 2014
The parsed date is: Tue Apr 01 00:00:00 ICT 2014

 

NOTE: When using the factory methods, we can set the date pattern as follows:

DateFormat dateFormat = DateFormat.getInstance();
SimpleDateFormat simpleDateFormatter = (SimpleDateFormat) dateFormat;
simpleDateFormatter.applyPattern("dd/MM/yyyy");

Then parse the date as same as previous code:

try {
	Date parsedDate = simpleDateFormatter.parse("27/03/1990");
	System.out.println("The parsed date is: " + parsedDate);
	
} catch (ParseException ex) {
	ex.printStackTrace();
}

This is the recommended way of using the date formatter in Java.

References:

• DateFormat class Javadoc
• SimpleDateFormat class Javadoc

  

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