Tyler DeWitt Tyler DeWitt - 1 month ago 7
Java Question

Java Unparsable date

I have a string with the format:

String dateString = "2014-03-17T20:05:49.2300963Z"


Trying this:

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'kk:mm:ss.SSSX");
Date date = df.parse(dateString);


Results in an
Unparsable date
exceptioon.

The docs: http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html indicate that
X
is used with
ISO 8601
when a single letter is used for the TimeZone.

EDIT
Re-reading the docs, I've switched up the
SimpleDateFormat
a little:

SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS");
dateString = dateString.replace("Z", "");


I take out the
Z
because I know the timezone, use
H
instead of
k
and add a couple more
S
for giggles.

Now the time is parsing, but incorrectly. Date is accurate, Time seems to be random.

EDIT 2
The problem is that java only allows millisecond accuracy, so
2300963
is being interpreted as 2300 seconds and 963 milliseconds. I'll need to format my string a little differently to get this to work.

EDIT 3
Turns out you can't have a fractional part of a second in Java. It has to be truncated to milliseconds. I ended up using a type made available to me by my database, but the general solution is to truncate the fractional part of the second to millisecond. I'll post example code of how to do that as an answer.

Answer

How to truncate the fractional seconds to milliseconds (because Java can't handle fractional seconds):

public String truncate(String dateString){
  int numberOfDigits = dateString.substring(dateString.indexOf("."), dateString.length() - 1).length();

  String justMilliSecondsDate = null;
  if (numberOfDigits == 3) {
    justMicrosDate = dateString;
    } 
  else if (numberOfDigits > 3) {
    justMilliSecondsDate = dateString.substring(0, dateString.length() - numberOfDigits + 3);
  } 
  else {
      justMilliSecondsDate = dateString;
      for (int i = numberOfDigits ; i < 3 ; i++) justMilliSecondsDate += "0";
  }

  return justMilliSecondsDate;
}