How to format a date String into desirable Date format

I was trying to format a string into date.

For this I have written a code:-

Calendar cal = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
System.out.println(sdf.format( cal.getTime() ));

This is fine.. But now I want to convert a string into a date formatted like above.. For example

String dt="2010开发者_如何学Python-10-22";

And the output should be like this:- 2010-10-22T00:00:00

How do I do this?

String dt = "2010-10-22";

SimpleDateFormat sdfIn = new SimpleDateFormat("yyyy-MM-dd");
ParsePosition ps = new ParsePosition(0)
Date date = sdfIn.parse(dt, pos)

SimpleDateFormat sdfOut = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");

System.out.println(sdfOut.format( date ));

This should do it for you, remember to wrap it in a try-catch block just in case.

DateFormat dt = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss"); 
try
{
Date today = dt.parse("2010-10-22T00:00:00");                       
System.out.println("Your Date = " + dt.format(today));       
} catch (ParseException e)    
{
//This parse operation may not be successful, in which case you should handle the ParseException that gets thrown.
//Black Magic Goes Here
} 

If your input is going to be ISO, you could also look at using the Joda Time API, like so:

LocalDateTime localDateTime = new LocalDateTime("2010-10-22");
System.out.println("Formatted time: " + localDateTime.toString());

The same class you use for output formatting of dates can also be used to parse dates on input.

• SimpleDateFormat reference

To use your example, to parse the sample date:

String dt = "2010-10-22";
SimpleDateFormat dateFormatter = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(dateFormatter.parse(dt));

The fields that are not specified (ie. hour, minutes, etc) will be 0. So your same code can be used to format the date on output.

Date Format Example

Containing the Conversion of String Date object from one format to another