SimpleDateFormat parse not honouring timezone - java

public static void main(String[] args) throws ParseException {
SimpleDateFormat dt = new SimpleDateFormat("MM dd yy");
dt.setLenient(false);
dt.setTimeZone(TimeZone.getTimeZone("Asia/Hong_Kong"));
Date date = dt.parse("05 14 16");
System.out.println(date);
}
Output: Fri May 13 21:30:00 IST 2016
If i try to use the output it is switching to one day before instead of the correct day.
Is this expected or an issue with the API?

This is expected and there is no bug in Java.
Class Date does not contain timezone information. A java.util.Date is nothing more than wrapper for a number of milliseconds since 01-01-1970, 00:00:00 GMT. It does not remember that the string that it was parsed from contained information about a timezone.
When you display a Date, for example by (implicitly) calling toString() on it as you are doing here:
System.out.println(date);
it will be printed in the default timezone of your system, which is IST in your case.
If you want to print it in a certain timezone, then format it using a SimpleDateFormat object, setting the desired timezone on the SimpleDateFormat object. For example:
DateFormat df = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss Z");
df..setTimeZone(TimeZone.getTimeZone("Asia/Hong_Kong"));
System.out.println(df.format(date));

Related

How to convert date from mm/dd/yyyy to mm dd, yyyy

I want to convert date from 07/02/2019 to July 07, 2019. My input value is 07/02/2019 I want to compare with target value July 07, 2019....Please help me on this...
public static void main(String[] args) throws ParseException {
String sDate1="07/01/2019";
java.util.Date date1=new SimpleDateFormat("MM/dd/yyyy").parse(sDate1);
System.out.println(date1);
Output:Mon Jul 01 00:00:00 IST 2019 which is not my expected value
Try this one.
SimpleDateFormat sdf = new SimpleDateFormat("dd/mm/yyyy");
SimpleDateFormat output = new SimpleDateFormat("MMMM dd, yyyy");
Date data = sdf.parse("07/02/2019");
String newDate = output.format(data);
System.out.println(newDate);
Here, you use:
java.util.Date date1=new SimpleDateFormat("MM/dd/yyyy").parse(sDate1);
to parse a date that comes in as String.
Then you print that date without any formatting information.
Thus the answer is quite simple: define a pattern for formatting a Date object as string! Same rules, same patterns. Just not parsing, but formatting for printing!
In other words: you already know the concept, you used a formatter to turn a String into a Date. Now simply turn that around, and provide a pattern to a formatter to turn a Date into a string!
Parse your input date
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MM/dd/uuuu");
LocalDate date = LocalDate.parse(sDate, formatter);
Similarly parse your target date
DateTimeFormatter targetFormatter = DateTimeFormatter.ofPattern("MMMM dd, uuuu", Locale.ENGLISH);
LocalDate targetDate = LocalDate.parse("July 07, 2019");
Or better yet, define your target date without using a string
LocalDate targetDate = LocalDate.of(2019, Month.JULY, 7);
Compare
if (date.equals(targetDate)) {
System.out.println("Same date");
}
LocalDate also have methods isBefore and isAfter.
This answer is entered from my tablet without trying the code out, so please forgive the typos.

SimpleDateFormat results in incorrect time

I have the following code
protected void amethod1() {
String strDate = "Thu May 18 16:24:59 UTC 2017";
String dateFormatStr = "EEE MMM dd HH:mm:ss zzz yyyy";
DateFormat dateFormat = new SimpleDateFormat(dateFormatStr);
Date formattedDate = null;
try {
formattedDate = dateFormat.parse(strDate);
} catch (ParseException e) {
e.printStackTrace();
}
}
The resulting value of formattedDate is- "Thu May 18 11:24:59 CDT 2017" .
I am testing this code in Chicago and the local timezone is CDT.
I am not able to understand why the time value changes from 16:24:59 to 11:24:59 even though. Am I missing something in the defined format of the date?
Class Date doesn't contain any timezone at all. It's just a number of milliseconds since 01.01.1970 00:00:00 GMT. If you try to see, what formattedDate contains with System.out.println or debugger, you'll get formatted date for your local timezone. 11:24:59 CDT and 16:24:59 UTC are the same time, so result is correct.
Is java.util.Date using TimeZone?
It is better to use jodatime or Java 8 Time API in order to better manage time and timezones.
First, you are getting the correct time. When Daylight Savings Time is in use in Chicago (which it is on May 18), the time is 11:24:59 when it’s 16:24:59 in UTC. So your Date value represents the same point in time. This is all you can expect from a Date.
I understand that you want not just a point in time, but also the UTC time zone. Since Axel P has already recommended Java 8 date and time API, I just wanted to fill in the details:
DateTimeFormatter parseFormatter = DateTimeFormatter.ofPattern(dateFormatStr, Locale.US);
ZonedDateTime dateTime = ZonedDateTime.parse(strDate, parseFormatter);
The result is
2017-05-18T16:24:59Z[UTC]
If you always want the UTC time zone, the Instant class is just right for it, so you will probably want to convert to it:
Instant instant = dateTime.toInstant();
Instants are always in UTC, popularly speaking.
SimpleDateFormat myFmt=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date now=new Date();
System.out.println(myFmt.format(now));
I hope I can help you. If you can,please adopt.Thank you
The resulting value of formattedDate is- "Thu May 18 11:24:59 CDT 2017" . Why? because your time zone running -5 hour from UTC time you will find in below link wiki time zone abbreviations, if you want result in same timezone you need to specify timezone in formater Hope you get my concern
https://en.wikipedia.org/wiki/List_of_time_zone_abbreviations
public static void amethod1() {
String strDate = "Thu May 18 16:24:59 UTC 2017";
String dateFormatStr = "EEE MMM dd HH:mm:ss zzz yyyy";
SimpleDateFormat dateFormat = new SimpleDateFormat(dateFormatStr);
dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
Date formattedDate = null;
try {
formattedDate = dateFormat.parse(strDate);
} catch (ParseException e) {
e.printStackTrace();
}
System.out.println("formattedDate: "+dateFormat.format(formattedDate));
}
You specified timezone, that's why after parsing time on current timezone (where you are), SimpleDateFormat sets UTC timezone. When you try to output your date, it is displayed on your current timezone
It appears you would need to specify the TimeZone as well when you format the Date For eg. .TimeZone.setDefault(TimeZone.getTimeZone("PST"));
Have a look at this discussion TimeZone
The output of a Date depends on the format specified, where you can specify the timezone, as shown in the example below:
protected void amethod2() {
String strDate = "Thu May 18 16:24:59 UTC 2017";
String dateFormatStr = "EEE MMM dd HH:mm:ss zzz yyyy";
DateFormat dateFormat = new SimpleDateFormat(dateFormatStr);
Date formattedDate = null;
try {
formattedDate = dateFormat.parse(strDate);
} catch (ParseException e) {
e.printStackTrace();
}
System.out.println("Date: " + formattedDate);
// Thu May 18 17:24:59 BST 2017, BST is my system default timezone
// Set the time zone to UTC for the calendar of dateFormat
dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
System.out.println("Date in timezone UTC: " + dateFormat.format(formattedDate));
// Thu May 18 16:24:59 UTC 2017
// Set the time zone to America/Chicago
dateFormat.setTimeZone(TimeZone.getTimeZone("America/Chicago"));
System.out.println("Date in timezone America/Chicago: " + dateFormat.format(formattedDate));
// Thu May 18 11:24:59 CDT 2017
}
As for the IDs, such as "UTC" and "America/Chicago" in the example, you can get a complete list of them via TimeZone.getAvailableIDs(). You can print them out to have a look:
Arrays.stream(java.util.TimeZone.getAvailableIDs()).forEach(System.out::println);
And you'll have:
Africa/Abidjan
Africa/Accra
Africa/Addis_Ababa
Africa/Algiers
Africa/Asmara
Africa/Asmera
Africa/Bamako
Africa/Bangui
Africa/Banjul
Africa/Bissau
Africa/Blantyre
...

I am getting java.text.ParseException

In the below code getting parsing error:please help.
DateFormat converter = new SimpleDateFormat("dd/MM/yyyy:HH:mm:ss");
converter.setTimeZone(TimeZone.getTimeZone("GMT"));
SimpleDateFormat formatter = new SimpleDateFormat("E, MMM dd yyyy");
Date date = formatter.parse(converter.format(new Date()));
I will try to explain what JB Nizet and others tried in the comments. In a simplified manner to make it understandable.
A Date is nothing else but a long which represents the time since epoch and a nice toString() method. Basically.
So if you create a Date date = new Date(); it sets the date's time value to System.currentTimeMillis();, nothing more, nothing less.
The interesting thing is that the Unix time is already "in UTC (=GMT)", if you want to say so.
If you now print the date like this
Date date = new Date();
System.out.println(date);
you implicitly call date.toString();.
This toString() can be seen as follows:
public String toString() {
return new SimpleDateFormat("E MMM dd HH:mm:ss z YYYY").format(this);
}
The SimpleDateFormat uses by default YOUR timezone. But it doesn't change the value of the date at all, it just prints it in another way.
If you now want to see the date in GMT you can simply set the SimpleDateFormat yourself:
Date date = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("E MMM dd HH:mm:ss z YYYY");
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
System.out.println(sdf.format(date));
To push it further you could now write a simple static method somewhere to print dates in specific timezones:
public static void printDate(Date date) {
printDate(date, "GMT");
}
public static void printDate(Date date, String timeZone) {
printDate(date, TimeZone.getTimeZone(timeZone));
}
public static void printDate(Date date, TimeZone timeZone) {
SimpleDateFormat sdf = new SimpleDateFormat("E MMM dd HH:mm:ss z YYYY");
sdf.setTimeZone(timeZone);
System.out.println(sdf.format(date));
}
To see what we all are talking about (that the timestamp does never change) you can print both:
public static void printDate(Date date, TimeZone timeZone) {
SimpleDateFormat sdf = new SimpleDateFormat("E MMM dd HH:mm:ss z YYYY");
sdf.setTimeZone(timeZone);
System.out.println(sdf.format(date) + " has the timestamp " + date.getTime());
}
If we now do some simple tests we see these results:
Local Time:
Sat Feb 22 16:08:12 CET 2014 has the timestamp 1393081692749
GMT:
Sat Feb 22 15:08:12 GMT 2014 has the timestamp 1393081692749
PST:
Sat Feb 22 07:08:12 PST 2014 has the timestamp 1393081692749
As you can see the times are all correct for their timezones, and the timestamp itself is always the same.
So to answer your question: Your simple new Date();, as it's already written in the comments, already achieves what you want: the Date is always in UTC (which equals GMT).

How to get Current Date using GMT in android?

I want Current Date in GMT wise Timezone.I used following code.
public static Date getGMTDate(String dateFormat) throws ParseException
{
SimpleDateFormat dateFormatGmt = new SimpleDateFormat(dateFormat);
dateFormatGmt.setTimeZone(TimeZone.getTimeZone("GMT"));
// Local time zone
SimpleDateFormat dateFormatLocal = new SimpleDateFormat(dateFormat);
// Time in GMT
return dateFormatLocal.parse(dateFormatGmt.format(new Date()));
}
//call above function.
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
date = getGMTDate("yyyy-MM-dd HH:mm:ss");
when i will change my device date then time is display in GMT formate but Date is not display in GMT timezone.its display of device's date.
but I want Current GMT Date.
This may works
SimpleDateFormat dateFormatGmt = new SimpleDateFormat("dd:MM:yyyy HH:mm:ss");
dateFormatGmt.setTimeZone(TimeZone.getTimeZone("GMT"));
System.out.println(dateFormatGmt.format(new Date())+"");
Specify the format, and you will get it in GMT!
EDIT: You can also check This
I changed your method as below
public static String getGMTDate() {
DateFormat dateFmt = SimpleDateFormat.getDateTimeInstance(SimpleDateFormat.MEDIUM, SimpleDateFormat.MEDIUM);
dateFmt.setTimeZone(TimeZone.getTimeZone("GMT"));
// Time in GMT
return dateFmt.format(new Date());
}
And got the following date (which is same as what you wanted I believe)
07-18 10:41:54.525: D/test(6996): GMT Date is: **Jul 18, 2013 10:41:03 AM**
So simply call this method and it will return the GMT date in string format.
EDIT 1:
you are setting GMT time zone and not GMT Date. You are not trying to understand your code. When you called new Data() it returned your device date, and then you formatted it for the corresponding GMT date and time. So if your change your device date to 16th July then your code (or even my code) will return the GMT equivalent of 16th July time. If you want 18th July GMT time even when your device's date is 16th July 2000, then I don't think you can do it without getting it from some network entity.
EDIT 2:
You should look at this SO reference to a similar kind of problem and it may serve you well.
Output: 2016-08-01 14:37:48 UTC
final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z");
dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
Works fine.

Exception in parsing date format [duplicate]

This question already has answers here:
Date Format JAVA
(5 answers)
Closed 9 years ago.
I have a date in the following format
//input date
Thu Jun 06 2013 00:00:00 GMT+0530 (India Standard Time)
//output date format
I want to change this to "dd-mm-yyyy, hh:mm:ss".
I get the input date format from db. I have to change that into output date format which i will be showing it in a grid.
I tried the following code.
DateFormat outputDate = new SimpleDateFormat("dd-mm-yyyy, hh:mm:ss");
try
{
Date date = outputDate.parse(facade.getDate.toString()); **//getting exception here**
outputDate = new SimpleDateFormat("dd-mm-yyyy, hh:mm:ss");
Date date1 = new SimpleDateFormat("dd-mm-yyyy, hh:mm:ss").parse(outputDate
.format(date));
facade.setDate(date1);
}catch (ParseException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
I am getting
java.text.ParseException: Unparseable date: "2013-06-06 00:00:00.0".
Any help..
"2013-06-06 00:00:00.0" does not match "dd-mm-yyyy, hh:mm:ss" your format should be "dd-MM-yyyy hh:mm:ss" instead
But, looking at your code I'm guessing facade.getDate is actually a java.sql.Timestamp which inherits from java.util.Date so you can directly pass it to the format like so
new SimpleDateFormat("dd-MM-yyyy, hh:mm:ss").format(facade.getDate)
Here's some code which works for me:
import java.text.*;
import java.util.*;
public class Test {
public static void main(String[] args) throws Exception {
String input = "Thu Jun 06 2013 00:00:00 GMT+0530 (India Standard Time)";
DateFormat inputFormat = new SimpleDateFormat("E MMM dd yyyy HH:mm:ss 'GMT'z",
Locale.ENGLISH);
Date date = inputFormat.parse(input);
DateFormat outputFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss",
Locale.ENGLISH);
outputFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
String output = outputFormat.format(date);
System.out.println(output);
}
}
Things to consider:
You need to work out your output time zone. Currently I've got it set to UTC, but that may not be what you want.
You really need to take a step back and think things through. You've clearly got two different formats - you're trying to convert from one to the other. So creating three different SimpleDateFormat objects all with the same format is never going to work.
You need to read documentation carefully... in SimpleDateFormat, M means month and m means minute; h uses the 12-hour clock and H uses the 24-hour clock.
This is assuming you actually need to start with a string though. If getDate is already a Date or a Timestamp, you can ignore the first part - just use the output part of the above code. You should avoid unnecessary string conversions wherever possible.
Note that dd-MM-yyyy is a slightly unusual format - are you sure you don't actually want yyyy-MM-dd which is more common (and sortable)?
DateFormat outputDate = new SimpleDateFormat("yyyy-dd-mm hh:mm:ss");
try {
Date date = outputDate.parse("2013-06-06 00:00:00.0");
System.out.println(new SimpleDateFormat("dd-mm-yyyy, hh:mm:ss").format(date));
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
works well, line 1 was incorrect. Your SimpleDateFormat.parse needs to be in the exact format of the input date. Then you want to output it in a different format so you make another one and set the format then call SimpleDateFormat.format(date) and I put a println on it.
Fault is here
DateFormat outputDate = new SimpleDateFormat("dd-mm-yyyy, hh:mm:ss");
pattern should be equals to Thu Jun 06 2013 00:00:00 GMT+0530 (India Standard Time). not to your out put strings pattern.
#Test
public void test() throws ParseException {
SimpleDateFormat sdf_org = new SimpleDateFormat("E MMM dd yyyy HH:mm:ss 'GMT'Z", Locale.ENGLISH);
Date d = sdf_org.parse("Thu Jun 06 2013 00:00:00 GMT+0530");
SimpleDateFormat sdf_target = new SimpleDateFormat("yyyy-mm-dd HH:mm:ss.SSS");
System.out.println(sdf_target.format(d));
}
output console : 2013-30-06 03:30:00.000

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