Hi looking for a sample code which will return a RandomDateTime as 1968-02-03 23:02:03 over a range (1960,1970).
YYYY-MM-DD HH:MM:SS.
my code is returning timezone in between which I don't want.
...
java.time
Random rand = new Random();
LocalDateTime minInclusive = LocalDateTime.of(1960, Month.JANUARY, 1, 0, 0);
LocalDateTime maxExclusive = LocalDateTime.of(1971, Month.JANUARY, 1, 0, 0);
int seconds = Math.toIntExact(ChronoUnit.SECONDS.between(minInclusive, maxExclusive));
int choice = rand.nextInt(seconds);
LocalDateTime randomDateTime = minInclusive.plusSeconds(choice);
System.out.println(randomDateTime);
Example output (from running just now):
1960-12-05T19:05:28
I am using LocalDateTime because you said you wanted no time zone, but you risk getting a non-exisitng time, typically a time in the spring gap when the clocks are turned forward when sumer time (DST) begins. To avoid this risk, use ZonedDateTime and specify the time zone. The code will be very similar to the above.
Calling between on ChronoUnit.SECONDS calculates elapsed time as whole seconds.
The call to Math.toIntExact is a safer way to go from a 64-bit long to an 32-bit int. Throws an exception if the value overflows.
The output from printing randomDateTime is in ISO 8601 format. If you want a different format (for example, without the T in the middle), you may format it using a DateTimeFormatter. Search for how.
Link: Oracle tutorial: Date Time explaining how to use java.time.
You can get Randon date using ThreadLocalRandom class.
Here is quick fix for you. Please check following code.
Input :
Enter the Start Date: dd/mm/yyyy
01/01/1960
Enter the End Date: dd/mm/yyyy
01/01/1970
Output :
1969-04-18 06:30:54
Scanner input = null;
try {
input = new Scanner(System.in);
System.out.println("Enter the Start Date: dd/mm/yyyy");
String begin = new String();
begin = input.nextLine();
SimpleDateFormat startFormat = new SimpleDateFormat("dd/mm/yyyy");
Date startDate = startFormat.parse(begin);
System.out.println("Enter the End Date: dd/mm/yyyy");
String end = new String();
end = input.nextLine();
SimpleDateFormat endFormat = new SimpleDateFormat("dd/mm/yyyy");
Date endDate = endFormat.parse(end);
Date randomDate = new Date(ThreadLocalRandom.current()
.nextLong(startDate.getTime(), endDate.getTime()));
String pattern = "yyyy-MM-dd hh:mm:ss";
SimpleDateFormat simpleDateFormat = new SimpleDateFormat(pattern);
String randomDateFormat = simpleDateFormat.format(randomDate);
System.out.println(randomDateFormat);
}
catch (Exception ex) {
ex.printStackTrace();
}finally{
input.close();
}
Hope this solution works.
Related
I have to parse the following String into a more readable date format.
String date = "20190112151605.0Z";
However, I've never encountered the Z before. I know it has to do with the time zone but when I try to use my usual code I get a java.lang.NumberFormatException.
My code is as follows:
String whenChanged = "20190112151605.0Z";
long DIFF_NET_JAVA_FOR_DATE_AND_TIMES = 11644473600000L;
long adDate1 = Long.parseLong(whenChanged);
long adLongDate1 = ( adDate1 / 10000 ) - DIFF_NET_JAVA_FOR_DATE_AND_TIMES;
Date lastLogonDate1 = new Date(adLongDate1);
String format2 = new SimpleDateFormat("MM/dd/yyyy
HH:mma'Z'").format(lastLogonDate1);
Any help would be great. Thanks
This will do the trick. The Z means UTC time zone
DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyyMMddHHmmss.Sz");
ZonedDateTime parsed = ZonedDateTime.parse("20190112151605.0Z", fmt);
System.out.println(parsed); // prints 2019-01-12T15:16:05
See DateTimeFormatter
Is it necessary for you to do anything with these time zones?
If not you could do
if(whenChanged.contains('Z')){
whenChanged = whenChanged.substring(0,date.indexOf('Z'));
}
I have a date that keeps giving me an error of
java.text.ParseException: Unparseable date: " 5 April 2017 "
All other dates (without word months) work fine
The code I am using is below:
VisitDate=VisitDate.trim();
if (VisitDate.matches(".*[a-z].*")){
SimpleDateFormat changeDate = new SimpleDateFormat("dd_MMM_yy", Locale.UK);
//Convert the string to a date
Date date = changeDate.parse(VisitDate);
//Reformat the date the way I like it
SimpleDateFormat dt1 = new SimpleDateFormat("dd_MM_yy");
//Convert back into a string
try {
VisitDate=dt1.format(date);
if(VisitDate==null){
SimpleDateFormat dt2 = new SimpleDateFormat("dd MM yy");
//Convert back into a string
VisitDate=dt2.format(date);
if(VisitDate==null){
SimpleDateFormat dt3 = new SimpleDateFormat("dd MMMM yy");
//Convert back into a string
VisitDate=dt3.format(date);
if(VisitDate==null){
SimpleDateFormat dt4 = new SimpleDateFormat("d_MMM_yy");
//Convert back into a string
VisitDate=dt4.format(date);
if(VisitDate==null){
SimpleDateFormat dt5 = new SimpleDateFormat("d_MMMM_yy");
//Convert back into a string
VisitDate=dt5.format(date);
if(VisitDate==null){
SimpleDateFormat dt6 = new SimpleDateFormat("dd_MMM_yy");
//Convert back into a string
VisitDate=dt6.format(date);
if(VisitDate==null){
SimpleDateFormat dt7 = new SimpleDateFormat("dd_MMM_yyyy");
//Convert back into a string
VisitDate=dt7.format(date);
if(VisitDate==null){
SimpleDateFormat dt8 = new SimpleDateFormat("dd_MMMM_yyyy");
//Convert back into a string
VisitDate=dt8.format(date);
if(VisitDate==null){
VisitDate=VisitDate.replaceAll("\\s", "");
SimpleDateFormat dt9 = new SimpleDateFormat("dd MMMM yyyy");
//Convert back into a string
VisitDate=dt9.format(date);
}
}
}
}
}
}
}
}
} catch (Exception e) {
Logger.error(e+"->No visit Date frmo here with the original date as: "+date);
}
}
Happy to read your expressed interest in the modern date and time classes, here’s just a snippet to get you started:
String visitDate = " 5 April 2017 ";
DateTimeFormatter parseFormatter
= DateTimeFormatter.ofPattern("d MMMM uuuu", Locale.UK);
visitDate = visitDate.trim();
LocalDate date = LocalDate.parse(visitDate, parseFormatter);
// reformat to the string we like
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd_MM_uu");
visitDate = date.format(formatter);
The result is
05_04_17
I have spelled visitDate with a small v since the Java coding conventions recommend that variable names begin with a small letter.
The uu is subtle and probably something you can ignore. It’s a signed year where 0 equals 1 BC, -1 equals 2 BC and so forth. Assuming none of your dates are that old, you can use u and y interchangeably.
I believe that neither SimpleDateFormat.format() nor LocalDate.format() will ever return null, so all your null checks are superfluous.
Link for further reading: Oracle tutorial: Trail: Date Time
You only have one SimpleDateFormatter being used for parsing:
SimpleDateFormat changeDate = new SimpleDateFormat("dd_MMM_yy", Locale.UK);
//Convert the string to a date
Date date = changeDate.parse(VisitDate);
It is using the format dd_MMM_yy, however you are passing 4 digits for the year.
The rest of your SimpleDateFormatters are being used for formatting to a string, not parsing from a string. Only the first one will be called, since it will be able to produce a string given a valid date, and the following null checks will stop any other formatters from being used.
You have the input string to parse like this: " 5 April 2017 ". But you have no pattern match for this input
First please trim the space of input string
Second please change the format of your string or add another pattern to parse this string, because you have month April with 5 letter, but you have no pattern with MMMMM. Usually the month will be shorten to 3 letter like: April -> Apr, March -> Mar ...
I am trying to take date in string and its input format string and converting the date in output format. However after conversion into Date, the java code increases the number of hours by one. I am not able to understand what causes the bug.
My Code:
try {
DateFormat outputFormat = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss");
DateFormat inputFormat = new SimpleDateFormat(format);
Date date = inputFormat.parse(parameterValue);
parameterValue = outputFormat.format(date);
return parameterValue;
} catch (ParseException ex) {
// take action
}
format string: ddMMMyyyy / hh:mm z
Input Date: 07DEC2015 / 10:02 GMT
Output Date: 07/12/2015 11:02:00
outputFormat.setTimeZone(TimeZone.getTimeZone("GMT"));
resolved it.
If you don't want to use timezone, in java 8 you can use LocalDate/LocalTime/LocalDateTime:
LocalDateTime localDateTimeInstance = LocalDateTime.parse(dateToBeConverted, DateTimeFormatter.ofPattern(formatOfDateToBeConverted));
return localDateTimeInstance.format("dd/MM/yyyy hh:mm:ss");
/*
Also check out ZoneDate, ZoneTime (for timezone)
Checkout - LocalDate, LocalTime
*/
I am working on android app with achartengine where I am making a TimeSeries linegraph. I have stored all my variables inside an Arraylist. Since I need correct date object to insert in the time axis of my chart I am using,
int count = list.size();
Date[] dt = new Date[count];
for(int i=0;i<count;i++){
long a = Long.parseLong(list.get(i).get("time"));
dt[i] = new Date(a);
}
Here long a has the timestamp . With above piece of code. I am able to get dt as 09-Apr-2014 but I need the date to be shown as 09-Apr 12:55 . How can I do that,
I tried using the folllowing
SimpleDateFormat sdfDate = new SimpleDateFormat("MM-dd HH:mm");
Date now = new Date();
String strDate = sdfDate.format(now);
But Since strDate is a string I cannot use it as dt[i] = strDate which will throws an error as one is Date and another is String.
How can I solve this ?
Thanks
You can solve it this way:
dt[i] = sdfDate.parse(strDate);
If you really just need the date strings, you can do this:
int count = list.size();
String[] dt = new String[count];
for (int i = 0; i < count; i++) {
long a = Long.parseLong(list.get(i).get("time"));
Date d = new Date(a);
SimpleDateFormat dateFormat = new SimpleDateFormat("MM-dd HH:mm");
dt[i] = dateFormat.format(d);
}
Or, if you actually need the Date array, just format the dates on the fly as you need them.
Your question is misguided - you are showing how you create Date objects in the code, yet what you want to fix is how you show them.
The Date array will have dates precisely to the millisecond. The default toString() method of the Date objects shows only the day, that's why you're not seeing the time.
It is inherently the UIs responsibility to decide on the format of time that it is going to print, hence you should pass the Date array to the UI (or up to the point of printing) and format them there.
The DateFormat can do both (date to string representation and back):
DateFormat formatter = new SimpleDateFormat( "dd-MM-yyyy HH:mm:ss" );
Date to String:
Date date = new Date();
String sDate = formatter.format( time );
String to Date:
Date date = formatter.parse(sDate );
When you store the date, you should store it as precise as possible (milliseconds). For displaying it as a string, you can use whatever format you want.
I've been struggling for a while with this piece of code for an Android app and I can't get the hang of it. I've read and tried every solution I found on stackoverflow and other places, but still no luck.
What I want to do is have a function to convert a string like "17.08.2012 05:35:19:7600000" to a UTC date and a function that takes an UTC date and converts it to a string like that.
String value = "17.08.2012 05:35:19:7600000";
DateFormat df = new SimpleDateFormat("dd.MM.yyyy HH:mm:ss:SSSSSSS");
try
{
Date today = df.parse(value);
System.out.println("Today = " + df.format(today) + " " + today.toGMTString());
}
catch (ParseException e)
{
e.printStackTrace();
}
This results in : Today = 17.08.2012 07:41:59:0000000 17 Aug 2012 04:41:59 GMT which are both wrong.
I tried setting SDF's timezone to UTC, no luck.
Another thing that I noticed: if I do df.setLenient(false);
It gives me : java.text.ParseException: Unparseable date: "17.08.2012 05:35:19:7600000" .
If anyone can provide me with some explanations / sample code, I would be very grateful. Thanks in advance
The result you are getting is absolutely right.
Let's analyze this:
17.08.2012 05:35:19:7600000
17: Day of month (17th)
08: Month of year (August)
2012: Year (2012)
05: Hour of day (5am)
35: Minute of hour (:35)
19: Second of minute (:19)
7600000: Milliseconds of second (7,600,000)
Now, the way the VM sees this is that you are declaring the time of day as 5:35:19am, then adding 7,600,000 milliseconds to it. 7,600,000 milliseconds = 7,600 seconds = 2 hours, 6 minutes, 40 seconds. 5:35:19am + 02:06:40 = 7:41:59am (and 0 milliseconds). This is the result you are getting. (It also appears that you are not setting the timezone properly, so the GMT string is 3 hours behind your result.)
If you want to retain the :7600000, to my knowledge this is not possible. As this can be simplified into seconds, the VM will automatically reduce it into the other time increments. The milliseconds (the SSSS) should be for storing values <1000.
I'd suggest you create a new SimpleDateFormat for your output; but remember that the milliseconds will be absorbed into the other times (since they are all stored as a single long in the Date object).
private String convertDate(String cdate)
{
SimpleDateFormat dateFormat = new SimpleDateFormat("dd.MM.yyyy HH:mm:ss:SSSSSSS");
SimpleDateFormat postFormater = new SimpleDateFormat("yyyy-MM-dd");
Date convertedDate;
try
{
convertedDate = dateFormat.parse(cdate);
cdate = postFormater.format(convertedDate);
}
catch (ParseException e)
{
Toast.makeText(getApplicationContext(),e.toString(),Toast.LENGTH_SHORT).show();
}
return cdate;
}
Try this.
This is what you need (but it will loose millisecond information):
"dd.MM.yyyy HH:mm:ss.'000000'"
If you used "dd.MM.yyyy HH:mm:ss.SSSSSS", then would get three leading zeros for your milliseconds.
If you used "dd.MM.yyyy HH:mm:ss.SSS'000'", then you could format a date, but not parse any date.
Try it out:
public static void main(String[] args) throws ParseException {
printDate("dd.MM.yyyy HH:mm:ss.SSS");//02.05.2010 21:45:58.073
printDate("dd.MM.yyyy HH:mm:ss.SSSSSS");//02.05.2010 21:45:58.000073
printDate("dd.MM.yyyy HH:mm:ss.SSS'000'");//02.05.2010 21:45:58.073000
printDate("dd.MM.yyyy HH:mm:ss.'000000'");//02.05.2010 21:45:58.000000
tryToParseDate("dd.MM.yyyy HH:mm:ss.SSS");//good
tryToParseDate("dd.MM.yyyy HH:mm:ss.SSSSSS");//good
tryToParseDate("dd.MM.yyyy HH:mm:ss.SSS'000'");//bad
tryToParseDate("dd.MM.yyyy HH:mm:ss.'000000'");//good
}
private static void printDate(String formatString) {
Date now = new Date();
SimpleDateFormat format = new SimpleDateFormat(formatString);
String formattedDate = format.format(now);
// print that date
System.out.println(formattedDate);
}
private static void tryToParseDate(String formatString) {
Date now = new Date();
SimpleDateFormat format = new SimpleDateFormat(formatString);
String formattedDate = format.format(now);
// try to parse it again
try {
format.parse(formattedDate);
System.out.println("good");
} catch (ParseException e) {
System.out.println("bad");
}
}
To drop the nanoseconds, use:
new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.")
Update: java.time
The Question and other Answers use terrible date-time classes that are now legacy. These flawed classes were years ago supplanted by the modern java.time classes defined in JSR 310. Avoid Calendar, DateFormat, Date, etc.
Define a formatting pattern with DateTimeFormatter.
String input = "17.08.2012 05:35:19:7600000";
DateTimeFormatter f = DateTimeFormatter.ofPattern( "dd.MM.uuuu HH:mm:ss:SSSSSSS" );
Parse.
LocalDateTime ldt = LocalDateTime.parse( input , f ) ;
A LocalDateTime object represents a date with a time of day, but lacks the context of a time zone or offset from UTC.
If you are certain the input text is intended to represent a moment as seen in UTC, having an offset of zero hours-minutes-seconds, then assign a ZoneOffset to produce an OffsetDateTime object.
OffsetDateTime odt = ldt.atOffset( ZoneOffset.UTC ) ;
See this code run live at Ideone.com.
ISO 8601
I suggest you educate the publisher of your data about the use of ISO 8601 standard formats when serializing date-time values to text.
The java.time classes use ISO 8601 formats by default when parsing/generating text.