Скачать или смотреть How to Parse and Format Dates with LocalDateTime in Java 8

Summary: Learn how to effectively parse and format dates using the LocalDateTime class in Java 8. This guide covers essential methods and examples to help you handle date and time operations efficiently.
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Java 8 introduced the java.time package, which includes the LocalDateTime class. This class is essential for handling dates and times without timezone information. Parsing and formatting dates are common tasks that are simplified with the new date-time API. This guide will show you how to use LocalDateTime to parse and format dates in Java 8.

Parsing Dates with LocalDateTime

Parsing dates refers to converting a string representation of a date into a LocalDateTime object. The DateTimeFormatter class is used to define the format of the input string.

Example: Parsing a String to LocalDateTime

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In this example:

dateString is the string representation of the date.

DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm") creates a formatter matching the date string pattern.

LocalDateTime.parse(dateString, formatter) parses the string into a LocalDateTime object.

Formatting Dates with LocalDateTime

Formatting dates is the process of converting a LocalDateTime object into a string representation. Again, DateTimeFormatter is used to define the desired format.

Example: Formatting a LocalDateTime to a String

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In this example:

LocalDateTime.now() gets the current date and time.

DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm") creates a formatter with the desired output pattern.

dateTime.format(formatter) converts the LocalDateTime object into a formatted string.

Common DateTime Patterns

Here are some common patterns you might use with DateTimeFormatter:

yyyy-MM-dd HH:mm:ss for full date and time.

yyyy/MM/dd for date with slashes.

dd-MM-yyyy HH:mm for day-month-year and hour-minute format.

Handling Exceptions

Parsing and formatting dates can throw DateTimeParseException if the input string does not match the expected pattern. It is a good practice to handle these exceptions to ensure robustness.

Example: Handling DateTimeParseException

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This example includes a try-catch block to handle DateTimeParseException, ensuring the program does not crash due to format issues.

Conclusion

Java 8's LocalDateTime class, combined with DateTimeFormatter, provides a powerful way to parse and format dates. By understanding the common patterns and handling exceptions, you can effectively manage date and time operations in your Java applications.