Java - Know the day of the week of the given String

Question

In android,I have a String of that format "2015-03-30T12:30:00" and I want to know which day of the week it is.

Testing with the device on the same day, with that function dayOfweek = 5 and dayOfWeek2 = 2 why?

if I try to create a new Date with year , month , day Its say is deprecated...

public int devolverDia(String hora)
{
    hora = hora.substring(0, 10);
    String weekdays[] = new DateFormatSymbols(Locale.ENGLISH).getWeekdays();
    Calendar c = Calendar.getInstance();

    int year = Integer.parseInt(hora.substring(0, 4));
    int month = Integer.parseInt(hora.substring(5, 7));
    int day = Integer.parseInt(hora.substring(8, 10));

    c.set(Calendar.YEAR, year);
    c.set(Calendar.MONTH, month);
    c.set(Calendar.DAY_OF_MONTH, day);

    int dayOfWeek = c.get(Calendar.DAY_OF_WEEK);


    c.setTime(new Date());
    int dayOfWeek2 = c.get(Calendar.DAY_OF_WEEK);


    return dayOfWeek;
}

Answer 1

The reason that you don't get the date that you expect is that the line

c.set(Calendar.MONTH, month);

expects a month number from 0 (for January) to 11 (for December). If you replace it with

c.set(Calendar.MONTH, month - 1);

this code will work.

However, a much better solution would be to use the parse method of the SimpleDateFormat class to convert your String to a Date.

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
c.setTime(format.parse(hora));