I want to do something like:
Date date = new Date(); // current date
date = date - 300; // substract 300 days from current date and I want to use this "date"
How to do it?
@JigarJoshi it's the good answer, and of course also @Tim recommendation to use .joda-time.
I only want to add more possibilities to subtract days from a java.util.Date
.
Apache-commons
One possibility is to use apache-commons-lang. You can do it using DateUtils
as follows:
Date dateBefore30Days = DateUtils.addDays(new Date(),-30);
Of course add the commons-lang
dependency to do only date subtract it's probably not a good options, however if you're already using commons-lang
it's a good choice. There is also convenient methods to addYears
,addMonths
,addWeeks
and so on, take a look at the api here.
Java 8
Another possibility is to take advantage of new LocalDate
from Java 8 using minusDays(long days)
method:
LocalDate dateBefore30Days = LocalDate.now(ZoneId.of("Europe/Paris")).minusDays(30);
I would really recommend you to use the DateTime library found here: https://www.joda.org/joda-time/
It's one of my very first dependencies I add to almost every single Java Project I build.
If you have some legacy code requiring Dates or Calendars you can convert it back from DateTimes.
So subtracting 300 days would be as easy as:
Date date = new Date(); // Or where ever you get it from
Date daysAgo = new DateTime(date).minusDays(300).toDate();
Java 8 Time API:
Instant now = Instant.now(); //current date
Instant before = now.minus(Duration.ofDays(300));
Date dateBefore = Date.from(before);
With Java 8 it's really simple now:
LocalDate date = LocalDate.now().minusDays(300);
A great guide to the new api can be found here.
As you can see HERE there is a lot of manipulation you can do. Here an example showing what you could do!
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Calendar cal = Calendar.getInstance();
//Add one day to current date.
cal.add(Calendar.DATE, 1);
System.out.println(dateFormat.format(cal.getTime()));
//Substract one day to current date.
cal = Calendar.getInstance();
cal.add(Calendar.DATE, -1);
System.out.println(dateFormat.format(cal.getTime()));
/* Can be Calendar.DATE or
* Calendar.MONTH, Calendar.YEAR, Calendar.HOUR, Calendar.SECOND
*/
I have created a function to make the task easier.
For 7 days after dateString:
dateCalculate(dateString,"yyyy-MM-dd",7);
To get 7 days upto dateString:
dateCalculate(dateString,"yyyy-MM-dd",-7);
public static String dateCalculate(String dateString, String dateFormat, int days) {
Calendar cal = Calendar.getInstance();
SimpleDateFormat s = new SimpleDateFormat(dateFormat);
try {
cal.setTime(s.parse(dateString));
} catch (ParseException e) {
e.printStackTrace();
}
cal.add(Calendar.DATE, days);
return s.format(cal.getTime());
}
You can easily subtract with calendar with SimpleDateFormat
public static String subtractDate(String time,int subtractDay) throws ParseException {
Calendar cal = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm", Locale.ENGLISH);
cal.setTime(sdf.parse(time));
cal.add(Calendar.DATE,-subtractDay);
String wantedDate = sdf.format(cal.getTime());
Log.d("tag",wantedDate);
return wantedDate;
}
c1.set(2017, 12 , 01); //Ex: 1999 jan 20 //System.out.println("Date is : " + sdf.format(c1.getTime()));
c1.add(Calendar.MONTH, -2); // substract 1 month
System.out.println
("Date minus 1 month : "
+ sdf.format(c1.getTime()));
来源:https://stackoverflow.com/questions/11882926/how-to-subtract-x-day-from-a-date-object-in-java