Module tools.jackson.databind
Package tools.jackson.databind.ext.javatime

Class JavaTimeInitializer

java.lang.Object
tools.jackson.databind.ext.javatime.JavaTimeInitializer
All Implemented Interfaces:
Serializable
public final class JavaTimeInitializer extends Object implements Serializable
Class that registers capability of deserializing and serializing (reading and writing) java.time values with the Jackson core.

In Jackson 3, the module is embedded in databind and handlers are automatically registered: approach is similar to one used by full JacksonModules.

Most java.time types are serialized as numbers (integers or decimals as appropriate) if the DateTimeFeature.WRITE_DATES_AS_TIMESTAMPS feature is enabled (or, for Duration, DateTimeFeature.WRITE_DURATIONS_AS_TIMESTAMPS), and otherwise are serialized in standard ISO-8601 string representation. ISO-8601 specifies formats for representing offset dates and times, zoned dates and times, local dates and times, periods, durations, zones, and more. All java.time types have built-in translation to and from ISO-8601 formats.

Granularity of timestamps is controlled through the companion features DateTimeFeature.WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS and DateTimeFeature.READ_DATE_TIMESTAMPS_AS_NANOSECONDS. For serialization, timestamps are written as fractional numbers (decimals), where the number is seconds and the decimal is fractional seconds, if WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS is enabled (it is by default), with resolution as fine as nanoseconds depending on the underlying JDK implementation. If WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS is disabled, timestamps are written as a whole number of milliseconds. At deserialization time, decimal numbers are always read as fractional second timestamps with up-to-nanosecond resolution, since the meaning of the decimal is unambiguous. The more ambiguous integer types are read as fractional seconds without a decimal point if READ_DATE_TIMESTAMPS_AS_NANOSECONDS is enabled (it is by default), and otherwise they are read as milliseconds.

Some exceptions to this standard serialization/deserialization rule:

  • Period, which always results in an ISO-8601 format because Periods must be represented in years, months, and/or days.
  • Year, which only contains a year and cannot be represented with a timestamp.
  • YearMonth, which only contains a year and a month and cannot be represented with a timestamp.
  • MonthDay, which only contains a month and a day and cannot be represented with a timestamp.
  • ZoneId and ZoneOffset, which do not actually store dates and times but are supported with this module nonetheless.
  • LocalDate, LocalTime, LocalDateTime, and OffsetTime, which cannot portably be converted to timestamps and are instead represented as arrays when WRITE_DATES_AS_TIMESTAMPS is enabled.
See Also: