Section 1.1: ISO_LOCAL_DATE_TIME

The ISO_LOCAL_DATE_TIME formatter is designed to format or parse dates without any offset, exemplified by the string 2024-08-03T10:15:30. It adheres to the ISO-8601 standards for local date-time representation.

Converting String to LocalDateTime:

String dateTimeStr = "2024-08-03T10:15:30";

LocalDateTime dateTime = LocalDateTime.parse(dateTimeStr, DateTimeFormatter.ISO_LOCAL_DATE_TIME);

System.out.println(dateTime);

Converting LocalDateTime to String:

LocalDateTime dateTime = LocalDateTime.now();

String formattedDate = dateTime.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME);

System.out.println(formattedDate);

Section 1.2: ISO_OFFSET_DATE_TIME

This formatter is used for date-time values that include an offset from Greenwich/UTC time, such as 2024-08-03T10:15:30+01:00. It is particularly useful for representing time in relation to the UTC/GMT offset.

Converting String to OffsetDateTime:

String offsetDateTimeStr = "2024-04-03T10:15:30+01:00";

OffsetDateTime offsetDateTime = OffsetDateTime.parse(offsetDateTimeStr, DateTimeFormatter.ISO_OFFSET_DATE_TIME);

System.out.println(offsetDateTime);

Converting OffsetDateTime to String:

OffsetDateTime offsetDateTime = OffsetDateTime.now();

String formattedDate = offsetDateTime.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME);

System.out.println(formattedDate);

Description: This video demonstrates how to utilize the DateTimeFormatter class in Java, focusing on various formatting options and use cases.

Section 1.3: ISO_ZONED_DATE_TIME

When you need to include timezone information in your output, ISO_ZONED_DATE_TIME is the appropriate formatter. It produces strings like 2024-04-03T10:15:30+01:00[Europe/Paris].

Converting String to ZonedDateTime:

String zonedDateTimeStr = "2024-04-03T10:15:30+01:00[Europe/Paris]";

ZonedDateTime zonedDateTime = ZonedDateTime.parse(zonedDateTimeStr, DateTimeFormatter.ISO_ZONED_DATE_TIME);

System.out.println(zonedDateTime);

Converting ZonedDateTime to String:

ZonedDateTime zonedDateTime = ZonedDateTime.now();

String formattedDate = zonedDateTime.format(DateTimeFormatter.ISO_ZONED_DATE_TIME);

System.out.println(formattedDate);

Section 1.4: ISO_DATE_TIME

This formatter combines the features of ISO_LOCAL_DATE_TIME and ISO_OFFSET_DATE_TIME, accommodating optional offsets and zones. It can interpret various formats like 2024-04-03T10:15:30, 2024-04-03T10:15:30+01:00, and 2024-04-03T10:15:30+01:00[Europe/Paris].

Converting String to LocalDateTime (with optional offset):

String dateTimeStr = "2024-04-03T10:15:30+01:00";

LocalDateTime dateTime = LocalDateTime.parse(dateTimeStr, DateTimeFormatter.ISO_DATE_TIME);

System.out.println(dateTime);

Converting LocalDateTime to String (with optional offset):

LocalDateTime dateTime = LocalDateTime.now();

String formattedDate = dateTime.format(DateTimeFormatter.ISO_DATE_TIME);

System.out.println(formattedDate);

Section 1.5: ISO_INSTANT

ISO_INSTANT is tailored for parsing and formatting timestamps in UTC, such as 2024-04-03T10:15:30Z. It provides a straightforward representation of a point in time.

Converting String to Instant:

String instantStr = "2024-04-03T10:15:30Z";

Instant instant = Instant.parse(instantStr, DateTimeFormatter.ISO_INSTANT);

System.out.println(instant);

Converting Instant to String:

Instant instant = Instant.now();

String formattedDate = DateTimeFormatter.ISO_INSTANT.format(instant);

System.out.println(formattedDate);

Section 1.6: Custom Formatting

In addition to the predefined constants, DateTimeFormatter allows for the creation of custom patterns using the ofPattern method. For instance, if you wish to format a date as dd/MM/yyyy HH:mm:ss, you can do so as follows:

Converting String to LocalDateTime with Custom Format:

String customDateTimeStr = "03/04/2024 10:15:30";

DateTimeFormatter customFormatter = DateTimeFormatter.ofPattern("dd/MM/yyyy HH:mm:ss");

LocalDateTime customDateTime = LocalDateTime.parse(customDateTimeStr, customFormatter);

System.out.println(customDateTime);

Converting LocalDateTime to String with Custom Format:

LocalDateTime customDateTime = LocalDateTime.now();

DateTimeFormatter customFormatter = DateTimeFormatter.ofPattern("dd/MM/yyyy HH:mm:ss");

String formattedDate = customDateTime.format(customFormatter);

System.out.println(formattedDate);