Converting Date Object from one format to another

guylikeme

See below output. I'm looking to convert the former date object to be in the latters format. Is there a way to do this in Java

START DATE IS

Sat Jan 17 20:30:42 GMT 1970

AND WE NEED IT TO BE

2016-02-12 23:56:15

pillphil

Is it a date object or a string?


SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy");
SimpleDateFormat output = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date d = sdf.parse(time);
String formattedTime = output.format(d);

https://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html

guylikeme

pillphil wrote: »

Is it a date object or a string?


SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy");
SimpleDateFormat output = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date d = sdf.parse(time);
String formattedTime = output.format(d);

https://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html

String. Thanks above seems to help.

What of i only have a long like below though...

public static String makeDateFromLong(long secondsSinceEpoch) {
Date date = new Date();
String dateAsString = "";
try {
date.setTime(secondsSinceEpoch);
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");
//date = simpleDateFormat.parse(date);
dateAsString = simpleDateFormat.format(date);
} catch (final Exception e) {
e.printStackTrace();
}
log.debug ("Returning " + dateAsString);
return dateAsString;
}

Seems to output "Returning 1970-01-17 20:30:43" when i pass it the secondsSinceEpoch of a date this year.

Im geussing that the commented parse bit needs a String but what to pass it

pillphil

guylikeme wrote: »

String. Thanks above seems to help.

What of i only have a long like below though...

public static String makeDateFromLong(long secondsSinceEpoch) {
Date date = new Date();
String dateAsString = "";
try {
date.setTime(secondsSinceEpoch);
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");
//date = simpleDateFormat.parse(date);
dateAsString = simpleDateFormat.format(date);
} catch (final Exception e) {
e.printStackTrace();
}
log.debug ("Returning " + dateAsString);
return dateAsString;
}

Seems to output "Returning 1970-01-17 20:30:43" when i pass it the secondsSinceEpoch of a date this year.

Im geussing that the commented parse bit needs a String but what to pass it

I think you are passing the seconds since epoch when you should be passing milliseconds since epoch.

guylikeme

You may be right. However, when i pass the milliseconds, i still get an odd date.


Outputting this

Raw date is 2016-02-12 23:56:15
1452642975000milliseconds since epoch for original start value
555000
After adding the two, start is 1452643530000
Date IS 2016-01-13 00:05:30 AND WE NEED IT TO BE 2016-02-12 23:56:15

Code is as follows in main

long startSinceEpoch = DateTimeUtil.getMillisSinceEpoch(start);
logger.debug(startSinceEpoch + "milliseconds since epoch for original start value");
long startMillisToAdjust = startSecondsToAdjust * 1000;
logger.debug("" + startMillisToAdjust);
long startAdjustedMillisSinceEpoch = startSinceEpoch + startMillisToAdjust;
logger.debug("After adding the two, start is " + startAdjustedMillisSinceEpoch);
String newStartDateFormatted = DateTimeUtil.makeDateFromLong(startAdjustedMillisSinceEpoch);
logger.debug("Date IS " + newStartDateFormatted + " AND WE NEED IT TO BE " + Constants.START_TIME);


The methods to parse date etc below

public static String makeDateFromString(String rawDate){
log.debug("Raw date is " + rawDate);
Date date = null;
String output = "";
try {
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");
date = simpleDateFormat.parse(rawDate);
output = simpleDateFormat.format(date);
} catch (final Exception e) {
e.printStackTrace(); }
return output;
}
public static long getMillisSinceEpoch(String rawDate){
log.debug("Raw date is " + rawDate);
Date date = null;
long secondsSinceEpoch = 0;
try {
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");
date = simpleDateFormat.parse(rawDate);

} catch (final Exception e) {
e.printStackTrace(); }
secondsSinceEpoch = date.getTime();
return secondsSinceEpoch;
}

public static String makeDateFromLong(long secondsSinceEpoch) {
Date date = new Date();
String dateAsString = "";
try {
date.setTime(secondsSinceEpoch);
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
dateAsString = simpleDateFormat.format(date);
date = simpleDateFormat.parse(dateAsString);


} catch (final Exception e) {
e.printStackTrace();
}
return dateAsString;
}

pillphil

The use of DD vs dd is causing the problem. D is the day in year, d is the day in month.