Conversion from 12 hours time to 24 hours time in java

Question

In my app, I have a requirement to format 12 hours time to 24 hours time. What is the method I have to use?

For example, time like 10

Answer 1

java.time

In Java 8 and later it could be done in one line using class java.time.LocalTime.

In the formatting pattern, lowercase hh means 12-hour clock while uppercase HH means 24-hour clock.

Code example:

String result =                                       // Text representing the value of our date-time object.
    LocalTime.parse(                                  // Class representing a time-of-day value without a date and without a time zone.
        "03:30 PM" ,                                  // Your `String` input text.
        DateTimeFormatter.ofPattern(                  // Define a formatting pattern to match your input text.
            "hh:mm a" ,
            Locale.US                                 // `Locale` determines the human language and cultural norms used in localization. Needed here to translate the `AM` & `PM` value.
        )                                             // Returns a `DateTimeFormatter` object.
    )                                                 // Return a `LocalTime` object.
    .format( DateTimeFormatter.ofPattern("HH:mm") )   // Generate text in a specific format. Returns a `String` object.
;

See this code run live at IdeOne.com.

15:30

See Oracle Tutorial.