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

Try this:

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

public class Main {
   public static void main(String [] args) throws Exception {
       SimpleDateFormat displayFormat = new SimpleDateFormat("HH:mm");
       SimpleDateFormat parseFormat = new SimpleDateFormat("hh:mm a");
       Date date = parseFormat.parse("10:30 PM");
       System.out.println(parseFormat.format(date) + " = " + displayFormat.format(date));
   }
}

which produces:

10:30 PM = 22:30

See: http://download.oracle.com/javase/1.5.0/docs/api/java/text/SimpleDateFormat.html

Answer 2

Try This

public static String convertTo24Hour(String Time) {
    DateFormat f1 = new SimpleDateFormat("hh:mm a"); //11:00 pm
    Date d = null;
    try {
        d = f1.parse(Time);
    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    DateFormat f2 = new SimpleDateFormat("HH:mm");
    String x = f2.format(d); // "23:00"

    return x;
}

Answer 3

   static String timeConversion(String s)
   {
    String s1[]=s.split(":");
    char c[]=s1[2].toCharArray();
    if(s1[2].contains("PM"))
    {
        int n=Integer.parseInt(s1[0]);
        n=n+12;
        return n+":"+s1[1]+":"+c[0]+c[1];
    }
    else``
    return s1[0]+":"+s1[1]+":"+c[0]+c[1];
     }

Answer 4

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

public class Main {
   public static void main(String [] args){
       try {
            DateFormat parseFormat = new SimpleDateFormat("dd-MM-yyyy hh:mm:ss a");
            String sDate = "22-01-2019 9:0:0 PM";
            Date date = parseFormat.parse(sDate);
            SimpleDateFormat displayFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
            sDate = displayFormat.format(date);
            LOGGER.info("The required format : " + sDate);
           } catch (Exception e) {}
      }
}

Answer 5

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.

Answer 6

Try this to calculate time difference between two times.

first it will convert 12 hours time into 24 hours then it will take diff between two times

String a = "09/06/18 01:55:33 AM";
            String b = "07/06/18 05:45:33 PM";
            String [] b2 = b.split(" ");
            String [] a2 = a.split(" ");
            SimpleDateFormat displayFormat = new SimpleDateFormat("HH:mm:ss");
            SimpleDateFormat parseFormat = new SimpleDateFormat("hh:mm:ss a");
            String time1 = null ;
            String time2 = null ;
            if ( a.contains("PM") && b.contains("AM")) {
                 
                 Date date = parseFormat.parse(a2[1]+" PM");
                 time1 = displayFormat.format(date);
                 time2 = b2[1];
            }else if (b.contains("PM") && a.contains("AM")) {
                Date date = parseFormat.parse(a2[1]+" PM");
                time1 = a2[1];
                time2 = displayFormat.format(date);
            }else if (a.contains("PM") && b.contains("PM")){
                Date datea = parseFormat.parse(a2[1]+" PM");
                Date dateb = parseFormat.parse(b2[1]+" PM");
                time1 = displayFormat.format(datea);
                time2 = displayFormat.format(dateb);
            }   
            System.out.println(time1);
            System.out.println(time2);      
            SimpleDateFormat format = new SimpleDateFormat("HH:mm:ss");
            Date date1 = format.parse(time1);
            Date date2 = format.parse(time2);
            long difference = date2.getTime() - date1.getTime(); 
            System.out.println(difference);
            System.out.println("Duration: "+DurationFormatUtils.formatDuration(difference, "HH:mm"));

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