Converting XX:XX AM/PM to 24 Hour Clock

Question

I have searched google and I cannot find out how you can take a string: xx:xx AM/PM (ex. 3:30 PM) and change it so that it is now in 24 hours.

So for example the previous time would be "15:30". I have looked into simply using if then statements to manipulate the string, however it seems very tedious. Is there any easy way to do this?

Input: 3:30 PM
Expected Output:  15:30

Answer 1

Try

  String time = "3:30 PM";

    SimpleDateFormat date12Format = new SimpleDateFormat("hh:mm a");

    SimpleDateFormat date24Format = new SimpleDateFormat("HH:mm");

    System.out.println(date24Format.format(date12Format.parse(time)));

output:

15:30

Answer 2

try this: 

String string = "3:35 PM";
    Calendar calender = Calendar.getInstance();
    DateFormat format = new SimpleDateFormat( "hh:mm aa");
    Date date;
    date = format.parse( string );
    calender.setTime(date);

    System.out.println("Hour: " + calender.get(Calendar.HOUR_OF_DAY));
    System.out.println("Minutes: " + calender.get(Calendar.MINUTE))

;

works fine and same result as what you would like.

Answer 3

Here is a link to the SimpleDateFormat Javadoc

This is the way to go :

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;


public class TimeParsing {

    public static void main(String[] args) {
        try {
            // Declare a date format for parsing
            SimpleDateFormat dateParser = new SimpleDateFormat("h:mm a");

            // Parse the time string
            Date date = dateParser.parse("3:30 PM");

            // Declare a date format for printing
            SimpleDateFormat dateFormater = new SimpleDateFormat("HH:mm");

            // Print the previously parsed time
            System.out.println(dateFormater.format(date));

        } catch (ParseException e) {
            System.err.println("Cannot parse this time string !");
        }
    }
}

Console output is : 15:30

Answer 4

SimpleDateFormat inFormat = new SimpleDateFormat("hh:mm aa");
SimpleDateFormat outFormat = new SimpleDateFormat("HH:mm");
String time24 = outFormat.format(inFormat.parse(yourTimeString));

also you can read more about converting times here http://deepeshdarshan.wordpress.com/2012/08/17/how-to-change-time-from-12-hour-format-to-24-hour-format-in-java/

Answer 5

Mine did not work till I added Locale like this:

SimpleDateFormat date12Format = new SimpleDateFormat("hh:mm aa", Locale.US);

Answer 6

You can easily use this method to convert AM/PM time to 24-hour format. Simply pass 12Hour format time to this method.

public static String convert_AM_PM_TimeTo_24(String ampmtime){
    SimpleDateFormat sdf = new SimpleDateFormat("hh:mm a");
    Date testTime = null;
    try {
        testTime = sdf.parse(ampmtime);
        SimpleDateFormat formatter = new SimpleDateFormat("HH:mm:ss");
        String newFormat = formatter.format(testTime);
        return newFormat;
    }catch(Exception ex){
        ex.printStackTrace();
        return ampmtime;
    }
}