How to set time to 24 hour format in Calendar

Question

I need to set the time on the current date. The time string is always in 24 hour format but the result I get is wrong:

  SimpleDateFormat df = new SimpleDate         


        

Answer 1

Here you will get all kinds of time related problems. I hope this will solve your problem.

public class MyClass {

    public static void main(String[] args) {


        Calendar cal = Calendar.getInstance();

        // To get the current hour
        int hour = cal.get(Calendar.HOUR_OF_DAY);
        System.out.println("hour: " + hour);

        // To get the current time in 12 hours format
        SimpleDateFormat sdf = new SimpleDateFormat("hh:mm a",Locale.US);
        String a = sdf.format(cal.getTime());
        System.out.println("Time: " + a);

        // To get the desired time in 12 hours format from 23 hours format
        cal.set(Calendar.HOUR_OF_DAY, 24);
        SimpleDateFormat sdf1 = new SimpleDateFormat("hh:mm a",Locale.ENGLISH);
        String a1 = sdf1.format(cal.getTime());
        System.out.println("Time: " + a1);

        /*  H Hour in day (0-23) 
            k Hour in day (1-24) 
        */

        //To get the desired time in 24 hours format as 0-23 or 1-24
        cal.set(Calendar.HOUR_OF_DAY, 24);
        SimpleDateFormat sdf2 = new SimpleDateFormat("HH:mm",Locale.ENGLISH);
        SimpleDateFormat sdf3 = new SimpleDateFormat("kk:mm",Locale.ENGLISH);
        String a2 = sdf2.format(cal.getTime());
        String a3 = sdf3.format(cal.getTime());
        System.out.println("Time: " + a2);
        System.out.println("Time: " + a3);

        //For example, time like 12:30 PM. How can i convert to 24 hours time in java?

        SimpleDateFormat bigFormat = new SimpleDateFormat("kk:mm");
        SimpleDateFormat smallFormat = new SimpleDateFormat("hh:mm a");

        Date date = null;
        try {
            date = smallFormat.parse("12:30 AM");
        } catch (ParseException e) {
            e.printStackTrace();
        }        
        System.out.println(smallFormat.format(date) + " = " + bigFormat.format(date));

    }

}

Answer 2

use SimpleDateFormat df = new SimpleDateFormat("HH:mm"); instead

UPDATE

@Ingo is right. is's better use setTime(d1);

first method getHours() and getMinutes() is now deprecated

I test this code

SimpleDateFormat df = new SimpleDateFormat("hh:mm");
  Date d1 = df.parse("23:30");
  Calendar c1 = GregorianCalendar.getInstance();
  c1.setTime(d1);
  System.out.println(c1.getTime());

and output is ok Thu Jan 01 23:30:00 FET 1970

try this

SimpleDateFormat df = new SimpleDateFormat("KK:mm aa");
  Date d1 = df.parse("10:30 PM");
  Calendar c1 = GregorianCalendar.getInstance(Locale.US);
  SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");  
  c1.setTime(d1);
  String str = sdf.format(c1.getTime());
  System.out.println(str);

Answer 3

You can set the calendar to use only AM or PM using

calendar.set(Calendar.AM_PM, int);

0 = AM

1 = PM

Hope this helps