I have Date in this format (2012-11-17T00:00:00.000-05:00). I need to convert the date into this format mm/yyyy.
I tried this way, but I am getting this Exception.
Exception in thread "main" java.lang.IllegalArgumentException: Cannot format given Object as a Date
at java.text.DateFormat.format(Unknown Source)
at java.text.Format.format(Unknown Source)
at DateParser.main(DateParser.java:14)
Please see my code below:
import java.text.SimpleDateFormat;
import java.util.Date;
public class DateParser {
public static void main(String args[]) {
String MonthYear = null;
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("mm/yyyy");
String dateformat = "2012-11-17T00:00:00.000-05:00";
MonthYear = simpleDateFormat.format(dateformat);
System.out.println(MonthYear);
}
}
8 Answers
DateFormat.format only works on Date values.
You should use two SimpleDateFormat objects: one for parsing, and one for formatting. For example:
// Note, MM is months, not mm
DateFormat outputFormat = new SimpleDateFormat("MM/yyyy", Locale.US);
DateFormat inputFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSX", Locale.US);
String inputText = "2012-11-17T00:00:00.000-05:00";
Date date = inputFormat.parse(inputText);
String outputText = outputFormat.format(date);
EDIT: Note that you may well want to specify the time zone and/or locale in your formats, and you should also consider using Joda Time instead of all of this to start with - it's a much better date/time API.
java.time
I should like to contribute the modern answer. The SimpleDateFormat class is notoriously troublesome, and while it was reasonable to fight one’s way through with it when this question was asked six and a half years ago, today we have much better in java.time, the modern Java date and time API. SimpleDateFormat and its friend Date are now considered long outdated, so don’t use them anymore.
DateTimeFormatter monthFormatter = DateTimeFormatter.ofPattern("MM/uuuu");
String dateformat = "2012-11-17T00:00:00.000-05:00";
OffsetDateTime dateTime = OffsetDateTime.parse(dateformat);
String monthYear = dateTime.format(monthFormatter);
System.out.println(monthYear);
Output:
11/2012
I am exploiting the fact that your string is in ISO 8601 format, the international standard, and that the classes of java.time parse this format as their default, that is, without any explicit formatter. It’s stil true what the other answers say, you need to parse the original string first, then format the resulting date-time object into a new string. Usually this requires two formatters, only in this case we’re lucky and can do with just one formatter.
