java-time – Row Coding

JPA support for Java 8 new date and time API

by Tarik

For Hibernate 5.X just add <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-java8</artifactId> <version>${hibernate.version}</version> </dependency> and @NotNull @Column(name = “date_time”, nullable = false) protected LocalDateTime dateTime; will work without any additional effort. See https://hibernate.atlassian.net/browse/HHH-8844 UPDATE: Please have a look at Jeff Morin comment: since Hibernate 5.2.x it is enough <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>5.2.1.Final</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-…</artifactId> <version>4.3.1.RELEASE</version> </dependency> See …

Java 8 Convert given time and time zone to UTC time

by Tarik

You are looking for ZonedDateTime class in Java8 – a complete date-time with time-zone and resolved offset from UTC/Greenwich. In terms of design, this class should be viewed primarily as the combination of a LocalDateTime and a ZoneId. The ZoneOffset is a vital, but secondary, piece of information, used to ensure that the class represents …

LocalDateTime to ZonedDateTime

by Tarik

Postgres has no such data type as TIMESTAMP. Postgres has two types for date plus time-of-day: TIMESTAMP WITH TIME ZONE and TIMESTAMP WITHOUT TIME ZONE. These types have very different behavior with regard to time zone information. The WITH type uses any offset or time zone information to adjust the date-time to UTC, then disposes …

Java 8 – DateTimeFormatter and ISO_INSTANT issues with ZonedDateTime

by Tarik

The ISO_INSTANT formatter is documented here – “This is a special case formatter intended to allow a human readable form of an Instant”. As such, this formatter is intended for use with an Instant not a ZonedDateTime. Formatting When formatting, ISO_INSTANT can format any temporal object that can provide ChronoField.INSTANT_SECONDS and ChronoField.NANO_OF_SECOND. Both Instant and …

Convert between LocalDate and XMLGregorianCalendar

by Tarik

Converting from LocalDate to XMLGregorianCalendar: LocalDate date = LocalDate.now(); GregorianCalendar gcal = GregorianCalendar.from(date.atStartOfDay(ZoneId.systemDefault())); XMLGregorianCalendar xcal = DatatypeFactory.newInstance().newXMLGregorianCalendar(gcal); Converting back is simpler: xcal.toGregorianCalendar().toZonedDateTime().toLocalDate();

Why does the Duration class not have ‘toSeconds()’ method?

by Tarik

Let’s look at what the docs say: This class models a quantity or amount of time in terms of seconds and nanoseconds. That basically means that the unit used to store the amount of time represented is seconds. For example, to store the duration 5 minutes and 10 nanoseconds, 300 (seconds) and 10 (nanoseconds) are …

How to format a ZonedDateTime to a String?

by Tarik

You can use java.time.format.DateTimeFormatter. https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html Here there is an example ZonedDateTime date = ZonedDateTime.now(); System.out.println(DateTimeFormatter.ofPattern(“dd/MM/yyyy – hh:mm”).format(date));

How to create Java time instant from pattern?

by Tarik

The string “9999-12-31” only contains information about a date. It does not contain any information about the time-of-day or offset. As such, there is insufficient information to create an Instant. (Other date and time libraries are more lenient, but java.time avoids defaulting these values) Your first choice is to use a LocalDate instead of an …

Java 8 LocalDate – How do I get all dates between two dates?

by Tarik

Assuming you mainly want to iterate over the date range, it would make sense to create a DateRange class that is iterable. That would allow you to write: for (LocalDate d : DateRange.between(startDate, endDate)) … Something like: public class DateRange implements Iterable<LocalDate> { private final LocalDate startDate; private final LocalDate endDate; public DateRange(LocalDate startDate, LocalDate …

`uuuu` versus `yyyy` in `DateTimeFormatter` formatting pattern codes in Java?

by Tarik

Within the scope of java.time-package, we can say: It is safer to use “u” instead of “y” because DateTimeFormatter will otherwise insist on having an era in combination with “y” (= year-of-era). So using “u” would avoid some possible unexpected exceptions in strict formatting/parsing. See also this SO-post. Another minor thing which is improved by …