Java DateTime convert - java

I'm converting a specific datetime fromat by deducting -5 minutes from the current date I retrieve:
csvFileDate is a list of dates with format, yyyyMMddhhmm. Below is the code I'm using but its converting the date wrong:
private SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddhhmm");
private List<String> csvFileDates = new ArrayList<String>();
....
Collections.sort(csvFileDates);
String currDate = csvFileDates.get(csvFileDates.size() -1);
System.out.println("DATE1 " + currDate);
Calendar c = Calendar.getInstance();
c.setTime(dateFormat.parse(currDate));
c.add(Calendar.MINUTE, -5);
System.out.println("DATE2 " + c.getTime());
output:
DATE1 201505181208
DATE2 Mon May 18 00:03:00 SGT 2015
Another:
DATE1 201505181213
DATE2 Mon May 18 00:08:00 SGT 2015
Any idea why?

You have 24 hours time format. So you have to use uppercase H for hours:
H Hour in day (0-23)
h Hour in am/pm (1-12)
private SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmm");
See the documantation of SimpleDateFormat for more details.

Use HH instead of hh for hour of the day, as stated here

Related

How to get selected month last date last timestamp in java?

From the below java code I'm getting a month First & last dateTimestamp, but here i need last dateTimestamp as - "Mon Aug 31 23:59:59 IST 2015" instead of - "Mon Aug 31 00:00:00 IST 2015"?
Calendar cal = Calendar.getInstance();
int year = 2015;
int month = 07;
cal.set(cal.DATE,1);
cal.set(cal.YEAR,year);
cal.set(cal.MONTH, month);
String firstDate = (cal.getActualMinimum(cal.DATE) + "/" + (month+1) + "/" +year);
System.out.println("firstDate-->"+"\t"+firstDate);
String lastDate = (cal.getActualMaximum(cal.DATE) + "/" + (month+1) + "/" +year);
System.out.println("lastDate-->"+"\t"+lastDate);
DateFormat firstFormat = new SimpleDateFormat("dd/MM/yyyy");
Date beginDate = firstFormat.parse(firstDate);
System.out.println("BeginDate Timestamp"+ "\t" + beginDate);
DateFormat secoundFormat = new SimpleDateFormat("dd/MM/yyyy");
Date endDate = secoundFormat.parse(lastDate);
System.out.println("endDate Timestamp"+ "\t" + endDate);
Output:->
firstDate--> 1/8/2015
lastDate--> 31/8/2015
BeginDate Timestamp Sat Aug 01 00:00:00 IST 2015
endDate Timestamp Mon Aug 31 00:00:00 IST 2015
Please help me if we have any solution.
If I understand your question, it looks as if you want to pass a year and month into a method, and get back the last day of the passed month.
I would suggest consider (in this order):
which jdk you use
configuration of calendar
configuration of timezone (maybe)
using jodatime
As of 1.8 many JodaTime-like features have been added to the jdk- e.g. see https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html (If you arent using 1.8 you can use the joda lib, assuming your organization allows it)
Calendar.getInstance() gives a default TimeZone and a default Locale, which means the definitions of the running JVM. You may or may not need to consider this and implement more than just getInstance(). See API javadoc.
Assuming a Gregeorian Calendar (hey, you could be Bahaian and have 19 months in the year ...) , here is one partial implementation using JDK 1.7, JodaTime jar 2.2, validation-1.0.0.GA jar:
#Test
public void testDate() {
final String dateStringOfFirstDay = "1.7.2015";
final Date lastDayOfMonth = getLastDayOfMonth(dateStringOfFirstDay);
Assert.assertNotNull(lastDayOfMonth);
//more assertions ...
}
private Date getLastDayOfMonth(#NotNull String dateStringOfFirstDay) {
//further validation here necessary according to required date format
DateTime dt = DateTime.parse(dateStringOfFirstDay);
return dt.dayOfMonth().withMaximumValue().toDate();
}
The defintion of DateFormat/DateTimeFormat and further result assertions is left up to you.
Best of luck!
Guys I got a solution for my question!!!
I think it will help u too...
Calendar calendar = Calendar.getInstance();
int year=2015;
int month=7;
int date=31;
int hourOfDay=23;
int minute=59;
int second=59;
int milliSecond=999;
calendar.set(year, month, date, hourOfDay, minute, second);
calendar.set(calendar.MILLISECOND, milliSecond);
System.out.println("Time from Calendar: "+calendar.getTime());
long timeInMilliSeconds=calendar.getTimeInMillis();
System.out.println("timeInMilliSeconds from calendar: "+timeInMilliSeconds);
Timestamp timestamp=new Timestamp(timeInMilliSeconds);
System.out.println(timestamp);
The above program gives the last date last timestamp in a selected month.
getTimeInMillis() takes the time from Jan 01, 1970 to current time in Milliseconds.
Using those milliseconds i'm getting the Timestamp.
Thank you for your help guys!!!
OutPut:->
Time from Calendar: Mon Aug 31 23:59:59 IST 2015
timeInMilliSeconds from calendar: 1441045799999
2015-08-31 23:59:59.999

simpledateformat parse not parsing date properly

i am trying to print the date as : 2013/11/20 08 30 but it is printing as below after parsing the date through simpledateformat Wed Nov 20 14:00:00 IST 2013,
here i passed the HH and MM as 08 30 but after parsing it changed to 14:00:00
Can you please suggest
public class PrintDate {
public static void main(String[] args) {
System.out.println(getDate("2013/11/20","08","30"));
}
public static Date getDate(String date, String hour, String miniute) {
final SimpleDateFormat displayDateTimeFormat = new SimpleDateFormat("yyyy/MM/dd HH mm");
displayDateTimeFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
String paddedHour = hour.length() == 2 ? hour : "0" + hour;
int min = Integer.valueOf(miniute);
int remainder = min % 5;
int roundMinute = remainder > 2 ? min - remainder + 5 : min - remainder;
String minuteStr = String.valueOf(roundMinute);
String paddedMinuteStr = minuteStr.length() == 2 ? minuteStr : "0" + minuteStr;
String startDateStr = date + " " + paddedHour.toUpperCase() + " " + paddedMinuteStr;
Date startDate = null;
try {
startDate = displayDateTimeFormat.parse(startDateStr);
} catch (ParseException e) {
}
return startDate;
}
}
after parsing the date through simpledateformat Wed Nov 20 14:00:00 IST 2013, here i passed the HH and MM as 08 30 but after parsing it changed to 14:00:00
Yes, because you specified that you wanted it to be parsed as a UTC value. However, the Date itself has no concept of a time zone - it's just an instant in time. Date.toString() will always use the default time zone.
2013-11-20 08:30 UTC is the same instant in time as 2013-11-20 14:00 IST, so it's actually parsing it correctly - it's just the result of Date.toString() which is confusing you.
If you want to preserve the time zone as well, you'll have to do that separately - or (better) use Joda Time which is a much nicer date/time API, and has a DateTime class which represents an instant in time in a particular calendar system and time zone.
Just try below lines of code to get date in desired format -
Date date=new Date(2013-1900,10,20,8,30);
SimpleDateFormat dateFormat = new SimpleDateFormat("yyy/MM/dd K mm");
String strFormatDate = dateFormat.format(date);
Date dtFormatDate = dateFormat.parse(strFormatDate);
System.out.println("Formatted date in String:"+strFormatDate);
System.out.println("Formatted Date:"+dtFormatDate);
Just give K instead of HH in date format. You can give date as 14 30 then also this format will convert date as you desired.
Thanks

not getting proper date while parsing String date to Date

DateFormat formatter = new SimpleDateFormat("yy-mm-dd");
formatter.setLenient(false);
String[] dateStr = { "2013-12-27", "2013-01-03"};
for (int i = 0; i <= 1; i++) {
Date date = formatter.parse(dateStr[i]);
System.out.println("date is "+date);
}
result :
Sun Jan 27 00:12:00 IST 2013
Thu Jan 03 00:01:00 IST 2013
i am parsing string date in to Date.but it is giving me date Starting with month Jan regardless of what month i am passing to formatter constructor.
The format for your date would be yy-MM-dd. Update your format and check.
mm for minutes
MM for month
Use: "yy-MM-dd"
See here
once Silly Mistake
DateFormat formatter = new SimpleDateFormat("yy-MM-dd");
Format this line in your code

Date/time conversion/arithmetic

I've below code in Java 1.7:
DateFormat df = DateFormat.getInstance();
Date startDate = df.parse("07/28/12 01:00 AM, PST");
The above date time (07/28/12 01:00 AM, PST) is in the properties file which is configurable. If this date time is already passed, then I need to get the current date, set the time part from above string which is 01:00 AM PST in the current date & if this time is also already passed, then get the next day & set the time part from above string in it. The final object should be Date since I need to use it in Timer object.
How can I do this efficiently? Should I convert from date to Calendar or vice-versa? Can any one provide snippet?
You should look into the Calendar class. You can use constructs like:
Calendar cal = Calendar.getInstance();
cal.setTime(startDate);
cal.add(Calendar.DAY_OF_YEAR, 1);
It also has methods for checking if your startDate is before() or after() a new date (use the current time).
While writing of the built-in Java date/time structure, i would be remiss if i didnt plug Joda Time, considered by many to be superior to the native Java implementation.
EDIT:
It would be more efficient to show an example of the Date.compareTo() process, as the Calendar.before() and Calendar.after() require comparisons against other Calendar objects, which can be expensive to create.
take a look at the following:
DateFormat df = DateFormat.getInstance();
Date startDate = df.parse("07/28/12 01:00 AM, PST");
Calendar cal = Calendar.getInstance();
cal.setTime(startDate);
Date now = new Date();
if (startDate.compareTo(now)< 0) {
System.out.println("start date: " + startDate + " is before " + now);
Calendar nowCal = Calendar.getInstance();
nowCal.add(Calendar.DAY_OF_YEAR,1);
cal.set(Calendar.DAY_OF_YEAR, nowCal.get(Calendar.DAY_OF_YEAR));
} else if (startDate.compareTo(now) == 0) {
System.out.println("startDate: " +startDate + " is equal to " + now);
} else {
System.out.println("startDate: " + cal + " is after " + now);
}
System.out.println(cal.getTime());
I think this should work...your algorthim has my head spinning a little and I'm in a different time zone, so you original string didn't work :P
try {
DateFormat df = DateFormat.getInstance();
Date startDate = df.parse("28/07/2012 01:00 AM");
System.out.println("StartDate = " + startDate);
Date callDate = startDate;
Calendar today = Calendar.getInstance();
Calendar start = Calendar.getInstance();
start.setTime(startDate);
System.out.println("Today = " + today.getTime());
// If this date time is already passed
// Tue Jul 31 12:18:09 EST 2012 is after Sat Jul 28 01:00:00 EST 2012
if (today.after(start)) {
//then I need to get the current date, set the time part from above string in the current date
Calendar timeMatch = Calendar.getInstance();
timeMatch.setTime(startDate);
timeMatch.set(Calendar.DATE, today.get(Calendar.DATE));
timeMatch.set(Calendar.MONTH, today.get(Calendar.MONTH));
timeMatch.set(Calendar.YEAR, today.get(Calendar.YEAR));
//& if this time is also already passed, then get the next day & set the time part from above string in it
if (timeMatch.after(today)) {
timeMatch.add(Calendar.DATE, 1);
}
callDate = timeMatch.getTime();
}
System.out.println("CallDate = " + callDate);
} catch (ParseException exp) {
exp.printStackTrace();
}
This produces the following output
StartDate = Sat Jul 28 01:00:00 EST 2012
Today = Tue Jul 31 12:18:09 EST 2012
CallDate = Tue Jul 31 01:00:00 EST 2012

Compare date Java format problem

Trying to compare some dates in java but can't get the formatting right, where am i going wrong?
DateFormat df = new SimpleDateFormat("dd/mm/yyyy");
Date date1 = null, date2 = null, today = new Date();
date1 = (Date) df.parse(scan.next());
System.out.println(date1);
System.out.println(today);
if(date1.compareTo(today) < 0){
date1 = null;
System.out.println(start + " is not a valid date.. please try again!");
}
Please enter a start date:
10/04/2011
Mon Jan 10 00:04:00 GMT 2011
Tue Apr 05 22:27:44 BST 2011
I think you need MM, not mm
From the doc:
M Month in year
m Minute in hour
Change line 1 to be:
DateFormat df = new SimpleDateFormat("dd/MM/yyyy");
mm in SimpleDateFormat is the minutes. MM is the month. So your input is actaully January 10 2011 at 00:10:00
Check out http://download.oracle.com/javase/1.4.2/docs/api/java/text/SimpleDateFormat.html for abbreviations and javadoc.

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