Question

How to find previous date if current date is given as a String? Below is given my code. Is there any shorter solution?

   private static String previousDay(String date) {
        String[] ymd = date.split("-");
        int year = Integer.parseInt(ymd[0]);
        int month = Integer.parseInt(ymd[1]);
        int day = Integer.parseInt(ymd[2]);
        String newDate = "";
        if (day > 1 & month > 1)
            newDate = year+"-"+month+"-"+(day-1);
        else if (day == 1 & month > 1) {
            Calendar calendar = new GregorianCalendar(year,month-1, 1);
            int daysInMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
            newDate = year+"-"+(month-1)+"-"+daysInMonth;
        } else if (day == 1 & month == 1) {
            Calendar calendar = new GregorianCalendar(year,12, 1);
            int daysInMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
            newDate = year+"-"+12+"-"+daysInMonth;
        }
        return newDate;
    }

Answer 1

You need to convert your String to Date, in order to do date calculations. You can use Calender to find previous day. From your code, I assume, your date format is yyyy-MM-dd.

String input = "2009-09-30";
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
Date myDate = dateFormat.parse(input);
Calendar cal1 = Calendar.getInstance();
cal1.setTime(myDate);
cal1.add(Calendar.DAY_OF_YEAR, -1);
Date previousDate = cal1.getTime();