In my application i want get some data from server and i should cast date and time!
I receive date and time with this format end_date: "2020-04-08 13:11:14" from server.
I want get now date and time from my device and to calculate with above date (end_date), if this time under 24h i should show for example 15 hour later, but if this time more than 24h i should show 2 days later!
But i don't know how can i it?
Can you help me with send code or send to me other tutorials?!
I searched that but I didn't find anything.
java.time
The modern approach uses java.time classes.
Parse the input string as a LocalDateTime.
To parse, replace the SPACE in the middle with a T to comply with ISO 8601 standard.
String input = "2020-04-08 13:11:14".replace( " " , "T" ) ;
LocalDateTime ldt = LocalDateTime.parse( input ) ;
Your input lacks an indicator of any time zone or offset-from-UTC. So we do not know if this was meant to be 1 PM in Tokyo Japan, 1 PM in Toulouse France, or 1 PM in Toledo Ohio US. So you cannot reliably compare this to the current date and time.
If you want to presume this string was meant to tell time in your time zone, then assign a time zone to get a ZonedDateTime.
ZoneId z = ZoneId.of( "Asia/Tokyo" ) ;
ZonedDateTime then = ldt.atZone( z ) ;
Capture the current moment in the same zone.
ZonedDateTime now = ZonedDateTime.now( z ) ;
Calculate 24 hours later.
ZonedDateTime twentyFourHoursFuture = now.plusHours( 24 ) ;
Compare.
boolean within24Hours = then.isBefore( twentyFourHoursFuture ) ;
Determine elapsed time using the Duration class.
Duration duration = Duration.between( then , now ) ;
If you want to trust the JVM’s current default time zone, call ZoneId.systemDefault. Beware that this default can be changed by other Java code during execution of your app.
ZoneId z = ZoneId.systemDefault() ;
About java.time
The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.
Where to obtain the java.time classes?
Java SE 8, Java SE 9, Java SE 10, Java SE 11, and later - Part of the standard Java API with a bundled implementation.
Java 9 adds some minor features and fixes.
Java SE 6 and Java SE 7
Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
Later versions of Android bundle implementations of the java.time classes.
For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….
The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.
Try using the datetime library, or you can see this answer.
Also if you can choose, it's a good habit to pass the times in UTC from/to the server, it'll save some localization and timezone troubles.
Related
i have a Date field expiryDate with value Thu Nov 21 00:00:00 IST 2019 But i am trying to get the endDate time to the before to the day by removing a millisecond from the time as Thu Nov 20 23:59:59 IST 2019
do we have any methods to remove a millisecond from the given Date.
java.time
Avoid the terrible date-time classes that are now legacy as of JSR 310. Now supplanted by the modern java.time classes.
You can easily convert back and forth. Call new conversion methods addd to the old classes.
Instant instant = myJavaUtilDate.toInstant() ;
And back again.
java.util.Date myJavaUtilDate = Date.from( instant ) ;
Subtract a millisecond.
Instant oneMilliEarlier = instant.minusMillis( 1 ) ;
Half-Open
But I suggest you not take this approach. Do not track a span of time by its last moment.
Your attempt to track the last moment of the day is problematic. You are losing that last millisecond of time. Doing so leaves a gap until the first moment of the next day. And when switching to a finer time slicing such as microseconds used by some systems such as databases like Postgres, and the nanoseconds used by other software such as the java.time classes, you have a worse problem.
A better approach is the Half-Open approach commonly used in date-time handling. The beginning of a span-of-time is inclusive while the ending is exclusive.
So an entire day starts at the first moment of the day, typically at 00:00:00 (but not always!), and runs up to, but does not include, the first moment of the next day.
ZoneId z = ZoneId.of( "Asia/Kolkata" ) ;
ZonedDateTime zdt = ZonedDateTime.now( z ) ;
ZonedDateTime start = zdt.toLocalDate().atStartOfDay( z ) ;
ZonedDateTime stop = start.plusDays( 1 ) ;
Tip: For working with such spans of time, add the ThreeTen-Extra library to access the Interval class.
About java.time
The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.
Where to obtain the java.time classes?
Java SE 8, Java SE 9, Java SE 10, Java SE 11, and later - Part of the standard Java API with a bundled implementation.
Java 9 adds some minor features and fixes.
Java SE 6 and Java SE 7
Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
Later versions of Android bundle implementations of the java.time classes.
For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….
The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.
yes. i just tried with the above mehtod getTime() returns milliseconds to the given date.
and substracting a millisecond is giving me a correct output.
new Date(milliseconds) giving me the Date format.
Thanks #Elliott Frisch
I want to get the current time in milliseconds. I'm using System.currentTimeMillis() but this returns the date as well as the time. I simply want "15:03" in milliseconds, not the date too.
Note that I want an integer and not a formatted string. If it was 08:30, this is the equivalent to 30600 seconds, which is in turn equivalent to 30600000 milliseconds. This is the value I want
tl;dr
Duration.between( todayStart , now ).toMillis()
Details
Get the current moment in the wall-clock time used by the people of a certain region (a time zone).
ZoneId z = ZoneId.of( “Africa/Tunis” ) ;
ZonedDateTime now = ZonedDateTime.now( z ) ;
Get the first moment of the day. Do not assume this is 00:00:00. Let java.time determine.
ZonedDateTime todayStart = now.toLocalDate().atStartOfDay( z ) ;
Represent the delta between them, the span of time unattached to the timeline, as a Duration.
Duration d = Duration.between( todayStart , now ) ;
A Duration has a resolution of nanoseconds. That is finer than the milliseconds you desire. A convenience method will ignore any microseconds or nanoseconds for you.
long millisSinceStartOfToday = d.toMillis() ;
About java.time
The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.
Where to obtain the java.time classes?
Java SE 8, Java SE 9, and later
Built-in.
Part of the standard Java API with a bundled implementation.
Java 9 adds some minor features and fixes.
Java SE 6 and Java SE 7
Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
Later versions of Android bundle implementations of the java.time classes.
For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….
The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.
Use the LocalTime class:
long millis = LocalTime.now().toNanoOfDay() / 1_000_000;
Basil Bourque correctly points out that it isn’t always this simple: a Daylight Saving Time change (such as will occur in most of the US this Sunday) can mean that, for example, there may not be eight hours between midnight and 8 AM.
You can account for this by using a ZonedDateTime, which accounts for all calendar information, including DST changeovers:
ZonedDateTime now = ZonedDateTime.now();
ZonedDateTime start = now.truncatedTo(ChronoUnit.DAYS);
long millis = ChronoUnit.MILLIS.between(start, now);
Since you are interested in the millis since midnight in the GMT timezone, the easiest approach is probably:
int millis = LocalTime.now(ZoneOffset.UTC).get(ChronoField.MILLI_OF_DAY);
I am trying to send a date via JSON using a format like "date":"2018-01-03" but in my Java code I get 2018-01-03 02:00:00 and not 2018-01-03 00:00:00 as I would expect. Seems like it is adding some timezone to my date. Is this alright or am I missing something?
To represent a date-only value, use a date-only type rather than a date+time-of-day type.
LocalDate
LocalDate represents a date without a time-of-day and without a time zone.
LocalDate ld = LocalDate.of( "2018-01-03" ) ;
ZonedDateTime
To get the first moment of the day, specify a time zone.
ZoneId z = ZoneId.of( "Asia/Kolkata" ) ;
ZonedDateTime zdt = ld.atStartOfDay( z ) ;
Instant
To view that same moment in UTC, extract an Instant object from the ZonedDateTime.
Instant instant = zdt.toInstant() ;
These topics have been discussed many many times already. Search Stack Overflow for more info.
About java.time
The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
Where to obtain the java.time classes?
Java SE 8, Java SE 9, and later
Built-in.
Part of the standard Java API with a bundled implementation.
Java 9 adds some minor features and fixes.
Java SE 6 and Java SE 7
Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
The ThreeTenABP project adapts ThreeTen-Backport (mentioned above) for Android specifically.
See How to use ThreeTenABP….
The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.
From the Java API "The class Date represents a specific instant in time, with millisecond precision." When you create a Date you automatically get a date with a time. If you want to send just the date you have some options: 1. Convert the date to a string on the server side using the desired format. 2. On the client side ignore the time. 3. On the server side, zero the time fields, using methods such as setMinutes(0). But please note that these methods are deprecated in favor of Calendar methods, and further the old Date and Calendar classes are replaced by the Java 8 date and time classes.
I am getting getTimestampMillis() from a SmsMessage sms and trying to convert that to MM/dd/yy hh:mm a.
I am using the code below, which works except it returns an hour ahead. Example it is 6-28-15 9:22 pm, the code returns 6-28-15 10:22 pm. I have read this is a java bug because London didnt observe GMT in 1970, or something similar. Is there a fix, or workaround that doesn't require me to subtract an hour in the summer and then change the code back after DST?
long time = currentMessage.getTimestampMillis();
Log.i(TAG, "time stamp in millis= "+time);
Time date = new Time(time);
DateFormat format = new SimpleDateFormat("MM/dd/yy hh:mm a");
String timestamp = format.format(date);
Log.i(TAG, "Human readable timestamp= "+timestamp);
tl;dr
Instant.ofEpochMilli( millisSinceEpoch )
GMT represents mean solar time, and is practically synonymous with UTC. Do not confuse this with the time zone Europe/London which has observed Daylight Saving Time (DST).
java.time
Never use java.sql.Time, DateFormat, or any of the legacy date-time classes bundled with the earliest versions of Java.
The modern solution uses java.time classes.
I assume your count of milliseconds was since the epoch reference of first moment of 1970 in UTC, 1970-01-01T00:00Z.
long millisSinceEpoch = currentMessage.getTimestampMillis();
Convert to a Instant object.
Instant instant = Instant.ofEpochMilli( millisSinceEpoch ) ;
An Instant is always in UTC, by definition. So you will not have any surprises from Daylight Saving Time (DST).
Generate text in standard ISO 8601 format.
String output = instant.toString() ;
You did not specify your example value of epoch milliseconds. But we can work backwards to deduce it.
// Example it is 6-28-15 9:22
LocalDate ld = LocalDate.of( 2015 , Month.JUNE , 28 ) ;
LocalTime lt = LocalTime.of( 9 , 22 ) ;
LocalDateTime ldt = LocalDateTime.of( ld , lt ) ;
OffsetDateTime odt = ldt.atOffset( ZoneOffset.UTC ) ;
Instant instant = odt.toInstant() ;
long epochMilli = instant.toEpochMilli() ;
1435483320000
See this code run live at IdeOne.com.
About java.time
The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes. Hibernate 5 & JPA 2.2 support java.time.
Where to obtain the java.time classes?
Java SE 8, Java SE 9, Java SE 10, Java SE 11, and later - Part of the standard Java API with a bundled implementation.
Java 9 brought some minor features and fixes.
Java SE 6 and Java SE 7
Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
Later versions of Android (26+) bundle implementations of the java.time classes.
For earlier Android (<26), a process known as API desugaring brings a subset of the java.time functionality not originally built into Android.
If the desugaring does not offer what you need, the ThreeTenABP project adapts ThreeTen-Backport (mentioned above) to Android. See How to use ThreeTenABP….
UTC and GMT are two different things. UTC does not experience DST, whereas GMT does. Two steps:
1. Find out what time standard your host is actually using (java will be using this).
2. Probably just ignore that completely, and explicitly declare which timezone you want to use.
And if you find that playing with timezones is tedious, annoying, and confusing, consider using library joda-time. It's much more versatile and pleasant to use than built-in java stuff.
I have a Date object in Java. Sometimes the date's year is set to 17. When I go to output it using a SimpleDateFormat, it gets printed out as 0017. All my years are going to be in the 2000's. Is there a way to check if the year is belowe a certain value and then add 2000 to it if it is? Then once you do that, how do you recreate the Date object to use the new year? Seems like everything in the Date object is deprecated.
I would use a Calendar:
Date myDate = new Date();
Calendar cal = Calendar.getInstance();
cal.setTime(myDate);
int year = cal.get(Calendar.YEAR);
if(year < 2000)
cal.add(Calendar.YEAR, 2000); // add two thousand years
If you use Calendar or Joda Time (a better choice) you can get and set the year (or other fields)
Your year shouldn't be 17 in the first place. I would try to correct the problem at source rather than patch it later.
First of all, Date.getYear returns CurrentYear - 1900, not 2000, and it looks like you'll want to do that increment every time.
But since it's deprecated, you shouldn't use it in the first place, if possible. The API recommends you use the calendar class instead: http://docs.oracle.com/javase/1.4.2/docs/api/java/util/Calendar.html
java.time
If by Date you mean java.util.Date, that terribly designed class in now obsolete, years ago supplanted by the java.time classes defined in JSR 310.
Convert to its replacement, Instant, using new methods added to the old classes.
Instant instant = myJavaUtilDate.toInstant() ;
Both Instant and java.util.Date represent a moment in UTC. For any given moment, both time-of-day and date vary around the globe by zone. If you want to see the date through the wall-clock time of a particular time zone, apply ZoneId to get a ZonedDateTime.
ZoneID z = ZoneId.of( "Asia/Tokyo" ) ;
ZonedDatetTime zdt = instant.atZone( z ) ;
Now interrogate for the year.
int year = zdt.getYear() ;
Adjust. If that date in the different year is not valid (February 29 in non leap year), the ZonedDateTime class adjusts.
if( year < 1000 ) {
zdt = zdt.withYear( year + 2000 ) ; // You might also want to check for negative numbers. I'll omit that from this demo.
}
About java.time
The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.
Where to obtain the java.time classes?
Java SE 8, Java SE 9, Java SE 10, Java SE 11, and later - Part of the standard Java API with a bundled implementation.
Java 9 adds some minor features and fixes.
Java SE 6 and Java SE 7
Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
Later versions of Android bundle implementations of the java.time classes.
For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….
The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.