Kotlin DateTimeFormatter

The DateTimeFormatter class in Kotlin provides a mechanism to format and parse dates and times. It is used to format a date in a given format and also to parse a string and convert it into a date. In this article, we'll discuss how to use the DateTimeFormatter class in Kotlin.

Formatting a Date

To format a date, you need to create an instance of the DateTimeFormatter class with the desired format. Then, you can use the format method to format the date. Here's an example:

import java.time.LocalDate
import java.time.format.DateTimeFormatter

fun main() {
    val date = LocalDate.now()
    val formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy")
    val formattedDate = formatter.format(date)
    println(formattedDate)
}

In this example, we create a LocalDate object representing the current date. Then, we create an instance of the DateTimeFormatter class with the pattern "dd/MM/yyyy" to format the date as "day/month/year". We use the format method to format the date and store the result in the formattedDate variable. Finally, we print the formatted date using println.

The output of this program will be something like this:

12/06/2021

Parsing a String

To parse a string into a date, you need to create an instance of the DateTimeFormatter class with the same format as the string. Then, you can use the parse method to parse the string into a date. Here's an example:

import java.time.LocalDate
import java.time.format.DateTimeFormatter

fun main() {
    val dateString = "12/06/2021"
    val formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy")
    val parsedDate = LocalDate.parse(dateString, formatter)
    println(parsedDate)
}

In this example, we create a string representing the date "12/06/2021". Then, we create an instance of the DateTimeFormatter class with the pattern "dd/MM/yyyy" to parse the string into a date. We use the parse method to parse the string and store the result in the parsedDate variable. Finally, we print the parsed date using println.

The output of this program will be something like this:

2021-06-12

Conclusion

In this article, we discussed how to use the DateTimeFormatter class in Kotlin. We learned how to format a date using a given format and how to parse a string into a date using the same format. The DateTimeFormatter class is very useful when working with dates and times in Kotlin, and it provides a lot of flexibility in terms of formatting and parsing.