I tried like below, but in both the cases it is showing same time? What i am doing wrong.
LocalDateTime currentTime = LocalDateTime.now(ZoneId.of("UTC"));
Instant instant = currentTime.toInstant(ZoneOffset.UTC);
Date currentDate = Date.from(instant);
System.out.println("Current Date = " + currentDate);
currentTime.plusHours(12);
Instant instant2 = currentTime.toInstant(ZoneOffset.UTC);
Date expiryDate = Date.from(instant2);
System.out.println("After 12 Hours = " + expiryDate);
"Current Date" Time is showing Same as "After 12 Hours"...
The documentation of LocalDateTime specifies the instance of LocalDateTime is immutable, for example plusHours
public LocalDateTime plusHours(long hours)
Returns a copy of this LocalDateTime with the specified number of
hours added.
This instance is immutable and unaffected by this method call.
Parameters:
hours - the hours to add, may be negative
Returns:
a LocalDateTime based on this date-time with the hours added, not null
Throws:
DateTimeException - if the result exceeds the supported date range
So, you create a new instance of LocalDateTime when you execute plus operation, you need to assign this value as follows:
LocalDateTime nextTime = currentTime.plusHours(12);
Instant instant2 = nextTime.toInstant(ZoneOffset.UTC);
Date expiryDate = Date.from(instant2);
System.out.println("After 12 Hours = " + expiryDate);
I hope it can be helpful for you.
From the java.time package Javadoc (emphasis mine):
The classes defined here represent the principal date-time concepts,
including instants, durations, dates, times, time-zones and periods.
They are based on the ISO calendar system, which is the de facto world
calendar following the proleptic Gregorian rules. All the classes are
immutable and thread-safe.
Since every class in the java.time package is immutable, you need to capture the result:
LocalDateTime after = currentTime.plusHours(12);
...
This is simple, you can use
LocalDateTime's method "plusHours(numberOfHours)
Like This
localDateTime.plusHours(numberOfHours);
Related
My entity has createdAt field which is filled by #CreatedDate when the entity is created. This property is of Date type.
class MyEntity {
#CreatedDate
private Date createdAt;
}
I would like to filter out all entities in a List that are in a range from startDate to endDate. The problem is that when I used findAllByCreatedAtBetween(Date startDate, Date endDate); it worked but not for all cases. When the entity is created i.e.: 2019-10-25 14:15:23 I would like to get it also when the user will type as #RequestParam startDate from 2019-10-24 00:00 endDate to 2019-10-25 14:15 and also take this entity. How could I ignore everything that is behind minutes? Is there a way, because when I pass those values as startDate and endDate the entity isn't found, to find it I have to change 14:15 to 14:16.
You can set any parameter without others in LocalDateTime. For example you want handle without minute. You can set your search date parameter like this:
LocalDateTime localDateTime= myDate.atTime(14,15);//The first parameter is for Hour and other one is for minute.
You can find more detail here: Java Time LocalDateTime At Time Functions
I have a requirement to save the current UTC date with time in an Oracle column of type TIMESTAMP WITH TIMEZONE. this is from a Spring Boot service with JPA and Hibernate
I have enabled the following in my application yml
jpa:
hibernate:
ddl-auto: none
show-sql: true
properties:
hibernate:
dialect: org.hibernate.dialect.Oracle12cDialect
jdbc:
time_zone: UTC
and the Entity class field looks like
#Column(name = "last_user_edit_date", columnDefinition = "TIMESTAMP WITH TIME ZONE")
#JsonFormat(pattern = "yyyy-MM-dd'T'HH:mm:ss.SSSZ")
private ZonedDateTime lastUserEditDate;
While setting date I am using
obj.setLastUserEditDate(ZonedDateTime.of(LocalDateTime.now(), ZoneId.of("UTC")));
The above is working fine with respect to the actual date value. The only problem is in the database it is saving the UTC time but mentions MST (my local timezone) as the timezone. For eg a value saved is
12-SEP-19 09.50.53.820000000 PM AMERICA/DENVER
Here the 9.50 PM is actually the UTC time but the timezone comes as AMERICA/DENVER. What i want is
12-SEP-19 09.50.53.820000000 PM UTC
How can i achieve this Spring JPA and with Java 8 classes?
Thanks
LocalDateTime is the wrong class
The LocalDateTime class is not capable of tracking a moment in time. I cannot imagine a scenario where calling LocalDateTime.now() makes sense. Read the Javadoc before using a class.
Track a moment: Instant, OffsetDateTime, ZonedDateTime
To track a moment, use Instant (always in UTC), OffsetDateTime (a moment with an offset-from-UTC), or ZonedDateTime (a moment as seen in a particular region).
Oddly, JDBC 4.2 requires support for OffsetDateTime yet leaves the most common two classes, Instant & ZonedDateTime, optional.
So, to capture the current moment in UTC for JDBC work:
OffsetDateTime odt = OffsetDateTime.now( ZoneOffset.UTC ) ;
Or the longer:
Instant instant = instant.now() ; // Capture current moment in UTC.
OffsetDateTime odt = instant.atOffset( ZoneOffset.UTC ) ;
Send to database:
myPreparedStatement.setObject( … , odt ) ;
Retrieve from database:
OffsetDateTime odt = myResultSet.getObject( … , OffsetDateTime.class ) ;
JPA
I do not use JPA. But it looks this Question has you covered, JPA Storing OffsetDateTime with ZoneOffset. And see this post, What’s new in JPA 2.2 – Java 8 Date and Time Types.
Other time zones & offsets
only problem is in the database it is saving the UTC time but mentions MST
This documentation for Oracle Database seems to say that TIMESTAMP WITH TIME ZONE type does record the incoming data’s time zone or offset-from-UTC. Some other databases such as Postgres adjust incoming values to UTC (an offset of zero hours-minutes-seconds).
To get UTC, retrieve the OffsetDateTime as seen above, and call toInstant method to produce a Instant object which is always in UTC. Or produce another OffsetDateTime that is definitely in UTC:
OffsetDateTime odtUtc = odt.withOffsetSameInstant( ZoneOffset.UTC ) ;
I am trying to get LocalDateTime in certain format for my spring data jpa entity column.
I am not getting last 3 digits of millis/micros. I am not sure exactly what to call it.
I am always getting 000 for last 3 SSS portion even If I format
final String YYYY_MM_DD_HH_MM_SS_SSSSSS = "yyyy-MM-dd-HH.mm.ss.SSSSSS";
ZonedDateTime zdtAtUtc = ZonedDateTime.now(ZoneId.of("UTC"));
LocalDateTime ldt = zdtAtUtc.toLocalDateTime();
DateTimeFormatter destFormatter = DateTimeFormatter.ofPattern(YYYY_MM_DD_HH_MM_SS_SSSSSS);
System.out.println(zdtAtUtc);
System.out.println(zdtAtUtc.format(destFormatter));
System.out.println(ldt);
Output
2019-07-30T15:23:18.232Z[UTC]
2019-07-30-15.23.18.232000
2019-07-30T15:23:18.232
This is clock precision in Java 8.
If you'll check the code of now() method, it use behind an instant obtained like this:
Instant now = clock.instant();
In Java 8 output for this instant:
2019-08-02T20:44:35.722Z
In later versions:
2019-08-02T20:39:27.343408800Z
So if you need more precision, you need to switch to a newer version of java.
With Joda library, you can do
DateTimeFormat.forPattern("yyyy").parseLocalDate("2008")
that creates a LocalDate at Jan 1st, 2008
With Java8, you can try to do
LocalDate.parse("2008",DateTimeFormatter.ofPattern("yyyy"))
but that fails to parse:
Text '2008' could not be parsed: Unable to obtain LocalDate from TemporalAccessor: {Year=2008},ISO of type java.time.format.Parsed
Is there any alternative, instead of specifically writing sth like
LocalDate.ofYearDay(Integer.valueOf("2008"), 1)
?
LocalDate parsing requires that all of the year, month and day are specfied.
You can specify default values for the month and day by using a DateTimeFormatterBuilder and using the parseDefaulting methods:
DateTimeFormatter format = new DateTimeFormatterBuilder()
.appendPattern("yyyy")
.parseDefaulting(ChronoField.MONTH_OF_YEAR, 1)
.parseDefaulting(ChronoField.DAY_OF_MONTH, 1)
.toFormatter();
LocalDate.parse("2008", format);
String yearStr = "2008";
Year year = Year.parse(yearStr);
System.out.println(year);
Output:
2008
If what you need is a way to represent a year, then LocalDate is not the correct class for your purpose. java.time includes a Year class exactly for you. Note that we don’t even need an explicit formatter since obviously your year string is in the default format for a year. And if at a later point you want to convert, that’s easy too. To convert into the first day of the year, like Joda-Time would have given you:
LocalDate date = year.atDay(1);
System.out.println(date);
2008-01-01
In case you find the following more readable, use that instead:
LocalDate date = year.atMonth(Month.JANUARY).atDay(1);
The result is the same.
If you do need a LocalDate from the outset, greg449’s answer is correct and the one that you should use.
I didn't get you
but from the title I think you want to parse a String to a localdate so this is how you do it
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("d/MM/yyyy");
String date = "16/08/2016";
//convert String to LocalDate
LocalDate localDate = LocalDate.parse(date, formatter);
From a java.util.Date( a timestamp), how can I get the hour of day?
In joda.time I use getHourOfDay().
There are multiple solutions for this. If you wish to use the Java 8 classes from java.time the following you need to covert a Date to one of the DateTime classes. The following can be used to convert a Date to a ZonedDateTime where you then can get the hour:
Date date = new Date();
// Convert to java 8 ZonedDateTime
Date date = new Date();
final ZonedDateTime dateTime = date.toInstant()
.atZone(ZoneId.systemDefault());
// Get the hour
int hour = dateTime.getHour();
Quite verbose as you have noticed but the simple reason for this is that a Date is sort of an Instant
Despite its name, java.util.Date represents an instant on the time-line, not a "date". The actual data stored within the object is a long count of milliseconds since 1970-01-01T00:00Z (midnight at the start of 1970 GMT/UTC).
Another approach is simply to get the field from a Calendar instance.
final Calendar instance = Calendar.getInstance();
instance.setTime(date);
final int hourOfDay = instance.get(Calendar.HOUR_OF_DAY);