Parsing date from Calendar in Java - java

I am having following function
public static Date parseDate(String date, String format) throws ParseException
{
SimpleDateFormat formatter = new SimpleDateFormat(format);
return formatter.parse(date);
}
I am using this as follows in my code
Calendar eDate = Calendar.getInstance();
eDate.add(Calendar.DAY_OF_MONTH,10);
Date date = null;
try {
date = parseDate(eDate.getTime().toString(),"yyyy-MM-dd hh-mm-ss");
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
But it is throwing -
java.text.ParseException: Unparseable date
What is the problem here?

The format is not stored in the Date. It is stored in the String. The Date#toString() returns a fixed format which is described in its Javadoc.
Do the formatting only at the moment you need to display a Date to a human as a String.
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.DAY_OF_MONTH, 10);
Date date = calendar.getTime();
String formattedDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(date);
System.out.println(formattedDate);
Note that MM stands for months and mm for minutes. See also SimpleDateFormat javadoc.

You'll be happy to hear that there's never a need to parse a date from a Calendar object: The way to pull a Date out of a Calendar is via the getTime() method.
EDIT:
To output the date in eDate in ISO style format:
final DateFormat isoFormat = new SimpleDateFormat("yyyy-MM-dd HH-mm-ss");
String formattedDate = isoFormat.format(eDate.getTime());
That's untested, but I think it should work.

You're currently formatting with the default format from java.util.Date, and then parsing with a potentially different format. You should also change your format string - it's currently using a 12 hour clock with no am/pm indicator, and minutes twice. I think you mean: "yyyy-MM-dd HH-mm-ss"

Don't use toString() for anything like that. toString() should be used only for debug messages.
Use DateFormat.format(..) to produce a string in a predictable form.

You're inserting a Zulu Timestamp (UNIX), getTime() returns the number of milliseconds since January 1, 1970, 00:00:00 GMT. Then you define the format as yyyy-mm-dd hh-mm-ss and try to parse the timestamp with this pattern. Which doesn't match.
You could use Date date = calendar.getTime(); and then format it via new SimpleDateFormat("yyyy-MM-dd HH-mm-ss").format(date);

you can simply use the date returned by the calendar, instead of transforming it into string and back into a date (apparently using a wrong date format). The date can be obtained by:
eDate.getTime()
There seems to be no need for SimpleDateFormat in your case.

Check the Date.toString() method.
The api states that it returns it in
the format:
dow mon dd hh:mm:ss zzz yyyy
which is:
Mon Jan 28 14:22:07 EST 2004
You are telling the parser to expect: 2004-01-28 14-22-07

eDate.getTime().toString()
returns a String representation of a date in this format:
dow mon dd hh:mm:ss zzz yyyy (see the java.util.Date API).
You are trying to parse a date using this format:
yyyy-mm-dd hh-mm-ss .
The code is correctly throwing the ParseException.

Related

Simpledateformat ignoring setTimeZone call [duplicate]

This question already has answers here:
Convert date to different timezone [duplicate]
(3 answers)
Closed 5 years ago.
I have the following code:
SimpleDateFormat sdf = new SimpleDateFormat(format, Locale.getDefault());
sdf.setTimeZone(TimeZone.getDefault());
return sdf.format(date);
When I call this code with a date object, then it returns the same date (as String obviously) without setting the timezone.
As I understood a java.util.Date object is timezone independent. So if I set the timezone on the SimpleDateFormat then it should change. But it doesn't.
If I check sdf.getTimeZone() then I see that my timezone is set correctly to UTC+03:00.
Does someone know how to solve this problem?
To get the TimeZone in UTC Format
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd-MM-YYY HH:mm:ss Z",Locale.ENGLISH);
simpleDateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
return simpleDateFormat.format(new Date());
the above format gives results as 22-10-2017 18:05:50 UTC.
To get the TimeZone in Local Format (TimeZone of Phone or device)
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd-MM-YYY HH:mm:ss Z",Locale.ENGLISH);
simpleDateFormat.setTimeZone(TimeZone.getDefault());
return simpleDateFormat.format(new Date());
or
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd-MM-YYY HH:mm:ss Z",Locale.ENGLISH);
return simpleDateFormat.format(new Date());
the above format gives results as 22-10-2017 18:05:50 UTC+5:30.(Hint:-For India)
or
the above format gives results as 22-10-2017 18:05:50 IST.(Hint:-For India)
Hint : - if u pass this formatted String to Date like below
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd-MM-YYY HH:mm:ss Z",Locale.ENGLISH);
simpleDateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
Date d = null;
try {
d =simpleDateFormat.parse("22-10-2017 18:05:50 UTC");
} catch (ParseException e) {
e.printStackTrace();
}
return d.toString();
the returned output will be same as device timezone i.e local Timezone or default timezone . (22-10-2017 18:05:50 UTC+5:30 or 22-10-2017 18:05:50 IST).
even though the above timezone set is UTC you will get output in Device Timezone Only , if You pass your Content Into Your Date Object.
I think, the better way is use Joda Time instead. It's has a ZZ attribute in format, which gives you what you want.
Usage is easy:
DateTimeFormatter fmt = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ssZZ").withLocale(Locale.RU);

SimpleDateFormat sets current day for parsed date

Is there any way to use the following simpleDateFormat:
final SimpleDateFormat simpleDateFormatHour = new SimpleDateFormat("HH:mm:ss z");
and when invoking:
simpleDateFormat.parse("12:32:21 JST");
to return current date on the Date object?
For these example, it will return:
Thu Jan 01 05:32:21 EET 1970
and not:
<<today>> 05:32:21 EET <<currentYear>>
as I need.
No, SimpleDateFormat needs explicity the date in the input string. If you're using Java 8, you can go with a LocalDateTime:
LocalDateTime localDateTime = LocalDate.now().atTime(5, 32, 21);
If you want to include a time-zone, you can use ZonedDateTime.
Construct another SimpleDateFormat to print today's date:
String today = new SimpleDateFormat("yyyy/MM/dd").print(new Date());
(Be careful here: you might want to set the time zone on the SimpleDateFormat, as "today" is different in different time zones).
Update the date format to include year, month and day:
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss z");
And then prepend the date string with the date you want:
simpleDateFormat.parse(today + " " + "12:32:21 JST");
A better solution using flexible default values (today instead of 1970-01-01) would be in Java-8 with the new built-in date-time-library located in package java.time:
String input = "12:32:21 JST";
String pattern = "HH:mm:ss z";
LocalDate today = LocalDate.now(ZoneId.of("Asia/Tokyo"));
DateTimeFormatter dtf =
new DateTimeFormatterBuilder().parseDefaulting(ChronoField.YEAR, today.getYear())
.parseDefaulting(ChronoField.MONTH_OF_YEAR, today.getMonthValue()).parseDefaulting(
ChronoField.DAY_OF_MONTH,
today.getDayOfMonth()
).appendPattern(pattern).toFormatter(Locale.ENGLISH);
ZonedDateTime zdt = ZonedDateTime.parse(input, dtf);
System.out.println(zdt); // 2016-12-23T12:32:21+09:00[Asia/Tokyo]
However, I still see a small bug related to the fact that this code makes a hardwired assumption about the used zone BEFORE parsing the real zone so please handle with care. Keep in mind that the current date depends on the zone. But maybe you only need to handle a scenario where just the Japan time is used by users.
Hint: You can also parse in two steps. First step with any kind of fixed default date in order to get the zone information of the text to be parsed. And then you can use this zone information for suggested solution above. An awkward but safe procedure.
You can use this code if you want to change only the year and the day
final SimpleDateFormat simpleDateFormatHour = new SimpleDateFormat("HH:mm:ss z");
Date date = simpleDateFormatHour.parse("12:32:21 JST");
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
calendar.set(Calendar.YEAR, Calendar.getInstance().get(Calendar.YEAR));
calendar.set(Calendar.DAY_OF_YEAR, Calendar.getInstance().get(Calendar.DAY_OF_YEAR));
date = calendar.getTime();

How to convert date strings from different TimeZones to Date object in one TimeZone

Im working on an RSS reader software. I get items with their pubDate (publish date) values as string, convert them to Date object, and put them to my DB. However, when I check my DB, I saw some interesting values such as the date of tomorrow.
I research this situation and found that it is about time zone value Z. For example when I get "Mon, 26 May 2014 21:24:29 -0500", it becomes "2014-05-27 05:24:29", the next day !
All I want is to get dates in any timezone and convert them to date in common timezone, such as my country's.
Here is my code :
public static String convert(String datestr) throws ParseException {
DateFormat formatter = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz");
Date date = formatter.parse(datestr);
SimpleDateFormat resultFormatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return resultFormatter.format(date);
}
And I use the method like that :
System.out.println(convert("Mon, 26 May 2014 21:24:29 -0500"));
The output is : 2014-05-27 05:24:29
Any idea ?
Since you haven't set a time zone, it's using your system's default.
Set a specific IANA time zone.
SimpleDateFormat resultFormatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
resultFormatter.setTimeZone(TimeZone.getTimeZone("America/New_York"));
return resultFormatter.format(date);
Looks like you passed a Date with timezone, but given a wrong format. If you are passing timezone like "-0500" you should rather use:
DateFormat formatter = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z");
Remember that the system will always display the date using the current, default timezone (TimeZone.getDefault()) unless you override it by:
resultFormatter.setTimeZone(...)
This is working as expected. The date is converted as per your system's timezone.
Check the UTC offset of your system and replace it in the sample date string and look at the output.
For e.g: India is UTC+5:30
String datestr="Mon, 26 May 2014 21:24:29 +0530";
output:
2014-05-26 21:24:29
Alternate solution
If you don't want to consider the timezone of the input date string then simply truncate this information and remove zzz from pattern as well as shown in below code:
String datestr = "Mon, 26 May 2014 21:24:29 -0530";
datestr = datestr.replaceAll("\\s[-+](\\d+)$", ""); // truncate the timezone info if not needed
DateFormat formatter = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss"); // remove zzz from the pattern
Date date = formatter.parse(datestr);
SimpleDateFormat resultFormatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
System.out.println(resultFormatter.format(date));

Date converter in JAVA [duplicate]

This question already has answers here:
How to parse a date? [duplicate]
(5 answers)
Closed 9 years ago.
I have date like Tue Mar 19 00:41:00 GMT 2013, how to convert it to 2013-03-19 06:13:00?
final DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
final Date date = bdate;
Date ndate = formatter.parse(formatter.format(date));
System.out.println(ndate);
gives the same date.
Use two SimpleDateFormat objects with appropriate formats and use the first to parse the string into a date and the second to format the date into a string again.
As the first answer says. First parse your date with SimpleDateFormat like this:
Date from = new SimpleDateFormat("E M d hh:mm:ss z yyyy").parse("Tue Mar 19 00:41:00 GMT 2013");
Then use that to format the resulting date object with another instance of SimpleDateFormat like this:
String to = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(from);
See the javadoc of SimpleDateFormat here. Hope that helps.
One major thing that the others have left out is dealing with the timezone (TZ). Anytime you use a SimpleDateFormat to go to/from a string representation of the date, you really need to be aware of what TZ you're dealing with. Unless you explicitly set the TZ on the SimpleDateFormat, it will use the default TZ when formatting/parsing. Unless you only deal with date strings in the default timezone, you'll run into problems.
Your input date is representing a date in GMT. Assuming that you also want the output to be formatted as GMT, you need to make sure to set the TZ on the SimpleDateFormat:
public static void main(String[] args) throws Exception
{
String inputDate = "Tue Mar 19 00:41:00 GMT 2013";
// Initialize with format of input
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy");
// Configure the TZ on the date formatter. Not sure why it doesn't get set
// automatically when parsing the date since the input includes the TZ name,
// but it doesn't. One of many reasons to use Joda instead
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
Date date = sdf.parse(inputDate);
// re-initialize the pattern with format of desired output. Alternatively,
// you could use a new SimpleDateFormat instance as long as you set the TZ
// correctly
sdf.applyPattern("yyyy-MM-dd HH:mm:ss");
System.out.println(sdf.format(date));
}
Use SimpleDateFormat in this way:
final DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
final Date date = new Date();
System.out.println(formatter.format(date));
If you do any calculations or parsing with dates please use JodaTime because the standard JAVA date support is really buggy

Calendar date to yyyy-MM-dd format in java

How to convert calendar date to yyyy-MM-dd format.
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, 1);
Date date = cal.getTime();
SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-dd");
String date1 = format1.format(date);
Date inActiveDate = null;
try {
inActiveDate = format1.parse(date1);
} catch (ParseException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
This will produce inActiveDate = Wed Sep 26 00:00:00 IST 2012. But what I need is 2012-09-26. My purpose is to compare this date with another date in my database using Hibernate criteria. So I need the date object in yyyy-MM-dd format.
A Java Date is a container for the number of milliseconds since January 1, 1970, 00:00:00 GMT.
When you use something like System.out.println(date), Java uses Date.toString() to print the contents.
The only way to change it is to override Date and provide your own implementation of Date.toString(). Now before you fire up your IDE and try this, I wouldn't; it will only complicate matters. You are better off formatting the date to the format you want to use (or display).
Java 8+
LocalDateTime ldt = LocalDateTime.now().plusDays(1);
DateTimeFormatter formmat1 = DateTimeFormatter.ofPattern("yyyy-MM-dd", Locale.ENGLISH);
System.out.println(ldt);
// Output "2018-05-12T17:21:53.658"
String formatter = formmat1.format(ldt);
System.out.println(formatter);
// 2018-05-12
Prior to Java 8
You should be making use of the ThreeTen Backport
The following is maintained for historical purposes (as the original answer)
What you can do, is format the date.
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, 1);
SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(cal.getTime());
// Output "Wed Sep 26 14:23:28 EST 2012"
String formatted = format1.format(cal.getTime());
System.out.println(formatted);
// Output "2012-09-26"
System.out.println(format1.parse(formatted));
// Output "Wed Sep 26 00:00:00 EST 2012"
These are actually the same date, represented differently.
Your code is wrong. No point of parsing date and keep that as Date object.
You can format the calender date object when you want to display and keep that as a string.
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, 1);
Date date = cal.getTime();
SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-dd");
String inActiveDate = null;
try {
inActiveDate = format1.format(date);
System.out.println(inActiveDate );
} catch (ParseException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
java.time
The answer by MadProgrammer is correct, especially the tip about Joda-Time. The successor to Joda-Time is now built into Java 8 as the new java.time package. Here's example code in Java 8.
When working with date-time (as opposed to local date), the time zone in critical. The day-of-month depends on the time zone. For example, the India time zone is +05:30 (five and a half hours ahead of UTC), while France is only one hour ahead. So a moment in a new day in India has one date while the same moment in France has “yesterday’s” date. Creating string output lacking any time zone or offset information is creating ambiguity. You asked for YYYY-MM-DD output so I provided, but I don't recommend it. Instead of ISO_LOCAL_DATE I would have used ISO_DATE to get this output: 2014-02-25+05:30
ZoneId zoneId = ZoneId.of( "Asia/Kolkata" );
ZonedDateTime zonedDateTime = ZonedDateTime.now( zoneId );
DateTimeFormatter formatterOutput = DateTimeFormatter.ISO_LOCAL_DATE; // Caution: The "LOCAL" part means we are losing time zone information, creating ambiguity.
String output = formatterOutput.format( zonedDateTime );
Dump to console…
System.out.println( "zonedDateTime: " + zonedDateTime );
System.out.println( "output: " + output );
When run…
zonedDateTime: 2014-02-25T14:22:20.919+05:30[Asia/Kolkata]
output: 2014-02-25
Joda-Time
Similar code using the Joda-Time library, the precursor to java.time.
DateTimeZone zone = new DateTimeZone( "Asia/Kolkata" );
DateTime dateTime = DateTime.now( zone );
DateTimeFormatter formatter = ISODateTimeFormat.date();
String output = formatter.print( dateTime );
ISO 8601
By the way, that format of your input string is a standard format, one of several handy date-time string formats defined by ISO 8601.
Both Joda-Time and java.time use ISO 8601 formats by default when parsing and generating string representations of various date-time values.
java.util.Date object can't represent date in custom format instead you've to use SimpleDateFormat.format method that returns string.
String myString=format1.format(date);
public static void main(String[] args) {
Calendar cal = Calendar.getInstance();
cal.set(year, month, date);
SimpleDateFormat format1 = new SimpleDateFormat("yyyy MM dd");
String formatted = format1.format(cal.getTime());
System.out.println(formatted);
}
In order to parse a java.util.Date object you have to convert it to String first using your own format.
inActiveDate = format1.parse( format1.format(date) );
But I believe you are being redundant here.
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, 7);
Date date = c.getTime();
SimpleDateFormat ft = new SimpleDateFormat("MM-dd-YYYY");
JOptionPane.showMessageDialog(null, ft.format(date));
This will display your date + 7 days in month, day and year format in a JOption window pane.
public static String ThisWeekStartDate(WebDriver driver) {
Calendar c = Calendar.getInstance();
//ensure the method works within current month
c.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
System.out.println("Before Start Date " + c.getTime());
Date date = c.getTime();
SimpleDateFormat dfDate = new SimpleDateFormat("dd MMM yyyy hh.mm a");
String CurrentDate = dfDate.format(date);
System.out.println("Start Date " + CurrentDate);
return CurrentDate;
}
public static String ThisWeekEndDate(WebDriver driver) {
Calendar c = Calendar.getInstance();
//ensure the method works within current month
c.set(Calendar.DAY_OF_WEEK, Calendar.SATURDAY);
System.out.println("Before End Date " + c.getTime());
Date date = c.getTime();
SimpleDateFormat dfDate = new SimpleDateFormat("dd MMM yyyy hh.mm a");
String CurrentDate = dfDate.format(date);
System.out.println("End Date " + CurrentDate);
return CurrentDate;
}
I found this code where date is compared in a format to compare with date field in database...may be this might be helpful to you...
When you convert the string to date using simpledateformat, it is hard to compare with the Date field in mysql databases.
So convert the java string date in the format using select STR_to_DATE('yourdate','%m/%d/%Y') --> in this format, then you will get the exact date format of mysql date field.
http://javainfinite.com/java/java-convert-string-to-date-and-compare/
My answer is for kotlin language.
You can use SimpleDateFormat to achieve the result:
val date = Date(timeInSec)
val formattedDate = SimpleDateFormat("yyyy-MM-dd", Locale("IN")).format(date)
for details click here.
OR
Use Calendar to do it for you:
val dateObject = Date(timeInMillis)
val calendarInstance = Calendar.getInstance()
calendarInstance.time = dateObject
val date = "${calendarInstance.get(Calendar.YEAR)}-${calendarInstance.get(Calendar.MONTH)}-${calendarInstance.get(Calendar.DATE)}"
For more details check this answer.
I don't know about y'all, but I always want this stuff as a one-liner. The other answers are fine and dandy and work great, but here is it condensed to a single line. Now you can hold less lines of code in your mind :-).
Here is the one Liner:
String currentDate = new SimpleDateFormat("yyyy-MM-dd").format(new Date());

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