This post shows sample Kotlin codes that use the Java 8 Date and Time API (java.time).

Requirements

These are Software applications used for this post.

IntelliJ IDEA Ultimate 2016.3
- The Community Edition may be enough but we have not tried it.
Kotlin Version 1.1
Windows 10 Enterprise

Using java.time.LocalDate

package com.turreta.kotlin.java.time

import java.time.LocalDate

/**
 * Created by Turreta.com on 17/6/2017.
 */
fun main(args: Array<String>) {

    var localDateNow: LocalDate = LocalDate.now()

    val localDate: LocalDate = LocalDate.of(2015, 6, 6)

    println("Current Date: " + localDateNow)
    println("Some Date:" + localDate)
}

package com.turreta.kotlin.java.time

import java.time.LocalDate

/**

* Created by Turreta.com on 17/6/2017.

fun main(args: Array<String>) {

var localDateNow: LocalDate = LocalDate.now()

val localDate: LocalDate = LocalDate.of(2015, 6, 6)

println("Current Date: " + localDateNow)

println("Some Date:" + localDate)

}

Outputs:

Current Date: 2017-06-17
Some Date:2015-06-06

1 2	Current Date: 2017-06-17 Some Date:2015-06-06

Using java.time.LocalDateTime

package com.turreta.kotlin.java.time

import java.time.LocalDateTime

/**
 * Created by Turreta.com on 17/6/2017.
 */
fun main(args: Array<String>) {

    // Current date/time
    var localDateTimeNow: LocalDateTime = LocalDateTime.now()

    // June 6, 2015 8:30:10 AM
    val localDateTime: LocalDateTime = LocalDateTime.of(2015, 6, 6, 8, 30, 10)

    println("Current Date/time: " + localDateTimeNow)
    println("Some Date/time: " + localDateTime)
}

package com.turreta.kotlin.java.time

import java.time.LocalDateTime

/**

* Created by Turreta.com on 17/6/2017.

fun main(args: Array<String>) {

// Current date/time

var localDateTimeNow: LocalDateTime = LocalDateTime.now()

// June 6, 2015 8:30:10 AM

val localDateTime: LocalDateTime = LocalDateTime.of(2015, 6, 6, 8, 30, 10)

println("Current Date/time: " + localDateTimeNow)

println("Some Date/time: " + localDateTime)

}

Outputs:

Current Date/time: 2017-06-17T12:59:20.547
Some Date/time: 2015-06-06T08:30:10

1 2	Current Date/time: 2017-06-17T12:59:20.547 Some Date/time: 2015-06-06T08:30:10

Using java.time.LocalTime

package com.turreta.kotlin.java.time

import java.time.LocalTime

/**
 * Created by Turreta.com on 17/6/2017.
 */
fun main(args: Array<String>) {

    // Current time
    var localTimeNow: LocalTime = LocalTime.now()

    // 8:30:10 AM
    val localTime: LocalTime = LocalTime.of(8, 30, 10)

    println("Current time: " + localTimeNow)
    println("Some time: " + localTime)
}

package com.turreta.kotlin.java.time

import java.time.LocalTime

/**

* Created by Turreta.com on 17/6/2017.

fun main(args: Array<String>) {

// Current time

var localTimeNow: LocalTime = LocalTime.now()

// 8:30:10 AM

val localTime: LocalTime = LocalTime.of(8, 30, 10)

println("Current time: " + localTimeNow)

println("Some time: " + localTime)

}

Outputs:

Current time: 13:02:30.968
Some time: 08:30:10

1 2	Current time: 13:02:30.968 Some time: 08:30:10

Using java.time.Duration

Note that java.time.Duration works with classes that store both date and time. Depending on how we use Duration, it works with classes too that only store time.

package com.turreta.kotlin.java.time

import java.time.Duration
import java.time.LocalDateTime

/**
 * java.time.Duration example in Kotlin
 *
 * @author Turreta.com
 */
fun main(args: Array<String>) {

    // specificDateTime = February 2, 2017 9:00 AM
    var specificDateTime: LocalDateTime = LocalDateTime.of(2017, 2, 1, 9, 0, 0 )

    println(specificDateTime)

    // specificDateTime + 5 days
    println(specificDateTime.plus(Duration.ofDays(5)))

}

package com.turreta.kotlin.java.time

import java.time.Duration

import java.time.LocalDateTime

/**

* java.time.Duration example in Kotlin

* @author Turreta.com

fun main(args: Array<String>) {

// specificDateTime = February 2, 2017 9:00 AM

var specificDateTime: LocalDateTime = LocalDateTime.of(2017, 2, 1, 9, 0, 0 )

println(specificDateTime)

// specificDateTime + 5 days

println(specificDateTime.plus(Duration.ofDays(5)))

}

Outputs:

2017-02-01T09:00
2017-02-06T09:00

1 2	2017-02-01T09:00 2017-02-06T09:00

Using java.time.Period

Note that java.time.Period works with both classes that store date/time and date only. However. it will not work with classes that store time only.

package com.turreta.kotlin.java.time

import java.time.LocalDate
import java.time.LocalDateTime
import java.time.Period

/**
 * java.time.Period example in Kotlin
 *
 * @author Turreta.com
 */
fun main(args: Array<String>) {

    // specificDateTime = February 2, 2017 9:00 AM
    var specificDateTime: LocalDateTime = LocalDateTime.of(2017, 2, 1, 9, 0, 0 )

    println(specificDateTime)

    // specificDateTime - 5 days
    println(specificDateTime.minus(Period.ofDays(5)))

    // specifiDateOnly = July 4, 2020
    var specificDateOnly = LocalDate.of(2020, 7, 4)

    println(specificDateOnly)

    // specificDateOnly +  1 year
    println(specificDateOnly.plus(Period.ofDays(1)))

}

package com.turreta.kotlin.java.time

import java.time.LocalDate

import java.time.LocalDateTime

import java.time.Period

/**

* java.time.Period example in Kotlin

* @author Turreta.com

fun main(args: Array<String>) {

// specificDateTime = February 2, 2017 9:00 AM

var specificDateTime: LocalDateTime = LocalDateTime.of(2017, 2, 1, 9, 0, 0 )

println(specificDateTime)

// specificDateTime - 5 days

println(specificDateTime.minus(Period.ofDays(5)))

// specifiDateOnly = July 4, 2020

var specificDateOnly = LocalDate.of(2020, 7, 4)

println(specificDateOnly)

// specificDateOnly + 1 year

println(specificDateOnly.plus(Period.ofDays(1)))

}

Outputs:

2017-02-01T09:00
2017-01-27T09:00
2020-07-04
2020-07-05

2017-02-01T09:00

2017-01-27T09:00

2020-07-04

2020-07-05

Using java.time.temporal.ChronoUnit

package com.turreta.kotlin.java.time

import java.time.LocalDateTime
import java.time.temporal.ChronoUnit

/**
 * Created by Turreta.com on 17/6/2017.
 */
fun main(args: Array<String>) {

    // January 5, 2010 9:30:45 AM
    var startLocalDateTime: LocalDateTime = LocalDateTime.of(2010, 1, 5, 9, 30, 45)

    // June 6, 2015 8:30:10 AM
    val endLocalDateTime: LocalDateTime = LocalDateTime.of(2015, 6, 6, 8, 30, 10)

    println("Years: " + ChronoUnit.YEARS.between(startLocalDateTime, endLocalDateTime))

    println("Months: " + ChronoUnit.MONTHS.between(startLocalDateTime, endLocalDateTime))
    println("Weeks: " + ChronoUnit.WEEKS.between(startLocalDateTime, endLocalDateTime))
    println("Days: " + ChronoUnit.DAYS.between(startLocalDateTime, endLocalDateTime))
    println("Hours: " + ChronoUnit.HOURS.between(startLocalDateTime, endLocalDateTime))
    println("Minutes: " + ChronoUnit.MINUTES.between(startLocalDateTime, endLocalDateTime))
    println("Seconds: " + ChronoUnit.SECONDS.between(startLocalDateTime, endLocalDateTime))
    println("ms: " + ChronoUnit.MILLIS.between(startLocalDateTime, endLocalDateTime))
    println("ns: " + ChronoUnit.NANOS.between(startLocalDateTime, endLocalDateTime))
}

package com.turreta.kotlin.java.time

import java.time.LocalDateTime

import java.time.temporal.ChronoUnit

/**

* Created by Turreta.com on 17/6/2017.

fun main(args: Array<String>) {

// January 5, 2010 9:30:45 AM

var startLocalDateTime: LocalDateTime = LocalDateTime.of(2010, 1, 5, 9, 30, 45)

// June 6, 2015 8:30:10 AM

val endLocalDateTime: LocalDateTime = LocalDateTime.of(2015, 6, 6, 8, 30, 10)

println("Years: " + ChronoUnit.YEARS.between(startLocalDateTime, endLocalDateTime))

println("Months: " + ChronoUnit.MONTHS.between(startLocalDateTime, endLocalDateTime))

println("Weeks: " + ChronoUnit.WEEKS.between(startLocalDateTime, endLocalDateTime))

println("Days: " + ChronoUnit.DAYS.between(startLocalDateTime, endLocalDateTime))

println("Hours: " + ChronoUnit.HOURS.between(startLocalDateTime, endLocalDateTime))

println("Minutes: " + ChronoUnit.MINUTES.between(startLocalDateTime, endLocalDateTime))

println("Seconds: " + ChronoUnit.SECONDS.between(startLocalDateTime, endLocalDateTime))

println("ms: " + ChronoUnit.MILLIS.between(startLocalDateTime, endLocalDateTime))

println("ns: " + ChronoUnit.NANOS.between(startLocalDateTime, endLocalDateTime))

}

Outputs:

Years: 5
Months: 65
Weeks: 282
Days: 1977
Hours: 47470
Minutes: 2848259
Seconds: 170895565
ms: 170895565000
ns: 170895565000000000

Years: 5

Months: 65

Weeks: 282

Days: 1977

Hours: 47470

Minutes: 2848259

Seconds: 170895565

ms: 170895565000

ns: 170895565000000000

Download the codes

https://github.com/Turreta/Kotlin-Using-Java-8-Date-and-Time-API

Kotlin – Using Java 8 Date and Time API

Requirements

Using java.time.LocalDate

Using java.time.LocalDateTime

Using java.time.LocalTime

Using java.time.Duration

Using java.time.Period

Using java.time.temporal.ChronoUnit

Download the codes

References

Requirements

Using java.time.LocalDate

Using java.time.LocalDateTime

Using java.time.LocalTime

Using java.time.Duration

Using java.time.Period

Using java.time.temporal.ChronoUnit

Download the codes

References

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