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How do I add 2 weeks to a Date in java? [duplicate]

This question already has answers here:
Modify the week in a Calendar
(4 answers)
Closed 5 years ago.
I am getting a Date from the object at the point of instantiation, and for the sake of outputting I need to add 2 weeks to that date. I am wondering how I would go about adding to it and also whether or not my syntax is correct currently.
Current Java:
private final DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
private Date dateOfOrder;
private void setDateOfOrder()
{
//Get current date time with Date()
dateOfOrder = new Date();
}
public Date getDateOfOrder()
{
return dateOfOrder;
}
Is this syntax correct? Also, I want to make a getter that returns an estimated shipping date, which is 14 days after the date of order, I'm not sure how to add and subtract from the current date.

Use Calendar and set the current time then user the add method of the calendar
try this:
int noOfDays = 14; //i.e two weeks
Calendar calendar = Calendar.getInstance();
calendar.setTime(dateOfOrder);
calendar.add(Calendar.DAY_OF_YEAR, noOfDays);
Date date = calendar.getTime();

I will show you how we can do it in Java 8. Here you go:
public class DemoDate {
public static void main(String[] args) {
LocalDate today = LocalDate.now();
System.out.println("Current date: " + today);
//add 2 week to the current date
LocalDate next2Week = today.plus(2, ChronoUnit.WEEKS);
System.out.println("Next week: " + next2Week);
}
}
The output:
Current date: 2016-08-15
Next week: 2016-08-29
Java 8 rocks !!

Use Calendar
Date date = ...
Calendar c = Calendar.getInstance();
c.setTime(date);
c.add(Calendar.WEEK_OF_MONTH, 2);
date = c.getTime();

Try this to add two weeks.
long date = System.currentTimeMillis() + 14 * 24 * 3600 * 1000;
Date newDate = new Date(date);

if pass 14 to this addDate method it will add 14 to the current date and return
public String addDate(int days) throws Exception {
final DateFormat dateFormat1 = new SimpleDateFormat(
"yyyy/MM/dd HH:mm:ss");
Calendar c = Calendar.getInstance();
c.setTime(new Date()); // Now use today date.
c.add(Calendar.DATE, addDays); // Adding 5 days
return dateFormat1.format(c.getTime());
}

Using the Joda-Time library will be easier and will handle Daylight Saving Time, other anomalies, and time zones.
java.util.Date date = new DateTime( DateTimeZone.forID( "America/Denver" ) ).plusWeeks( 2 ).withTimeAtStartOfDay().toDate();

If you are on java 8 you can use new date time api http://docs.oracle.com/javase/8/docs/api/java/time/LocalDateTime.html#plusWeeks-long-
if you are on java 7 or more old version of java you should use old api http://docs.oracle.com/javase/8/docs/api/java/util/Calendar.html#add-int-int-

Java code for date functions [duplicate]

This question already has answers here:
How can I increment a date by one day in Java?
(32 answers)
How to subtract X day from a Date object in Java?
(10 answers)
Closed 8 years ago.
Can any one help me with the code for adding some number of days to any date..?
For example today is 11-04-2014. I want 15-04-2014 + 3 days output:18-04-2014.
My question is not adding dates to current date..

With Java 8, you can write:
import java.time.LocalDate;
LocalDate date = LocalDate.of(2014, 4, 11);
LocalDate newDate = date.plusDays(3);
System.out.println(newDate); // Prints 2014-04-14
Its that simple.

String dateString = "11-04-2014" // Say you have a date in String format
SimpleDateFormat format = new SimpleDateFormat("MM-dd-yyyy"); // Create an instance of SimpleDateFormat with the right format.
Date date = format.parse(dateString); // Then parse the string, this will need a try catch statement.
Calendar calendar = Calendar.getInstance(); // Get an instance of the calendar.
calendar.setTime(date); // Set the time of the calendar to the parsed date
calendar.add(Calendar.DATE, 3); // Add the days to the calendar
String outputFormat = format.format(calendar.getTime());

import java.util.Calendar;
import java.text.SimpleDateFormat;
public class A {
public static void main(String[] args) {
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd/MM/yyyy");
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_MONTH, 1);
calendar.set(Calendar.MONTH, 1);
calendar.set(Calendar.YEAR, 2012);
calendar.add(Calendar.DAY_OF_MONTH, 3);
System.out.println(simpleDateFormat.format(calendar.getTime()));
}
}

You can use the calendar function:
Calendar cal = Calendar.getInstance();
cal.setTime(dateInstance);
cal.add(Calendar.DATE, NO_OF_DAYS_TO_ADD);
Date addedDays = cal.getTime();
DateInstance is the date you are using. addedDays can be formatted using SimpleDateFormat to display in any date format that you would like to use.

How to display last six dates, java.util.Date?

I went to display the current date and the six (6) last dates
example :
02/11/2012
01/11/2012
31/10/2012
30/10/2012
29/10/2012
28/10/2012
to get the current day in JAVA I used :
Date date = Calendar.getInstance().getTime();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
System.out.println("current day : "+sdf.format(date));
but how do I decrement the days ?

You can use the Calendar#add method to substract a day, like:
SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
Calendar cal = Calendar.getInstance();
Date date=cal.getTime();
System.out.println(sdf.format(date)); //remove line to display only the last 5 days
for (int i=0;i<5;i++){
cal.add(Calendar.DAY_OF_MONTH,-1);
date=cal.getTime();
System.out.println(sdf.format(date));
}
Like Jon Skeet (soon Mr. 500k :) ) suggested, I too find the Joda Time API more cleaner and appropriate, even for such simple tasks:
DateTime dt = new DateTime();
for (int i = 0; i < 6; i++) {
System.out.println(dt.toString("yyyy/MM/dd"));
dt = dt.minusDays(1);
}

Calendar c = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
System.out.println("current day : "+sdf.format(c.getTime()));
// decrement 1 day
c.add(Calendar.DAY_OF_MONTH, -1);
// getTime() returns a java.util.Date
System.out.println("the day before : "+sdf.format(c.getTime()));
// getTimeInMillis() returns a long, which can be used to construct a java.sql.Date
System.out.println("the day before : "+sdf.format(new java.sql.Date(c.getTimeInMillis()));
And so on...

How to get last month/year in java?

How do I find out the last month and its year in Java?
e.g. If today is Oct. 10 2012, the result should be Month = 9 and Year = 2012. If today is Jan. 10 2013, the result should be Month = 12 and Year = 2012.

Your solution is here but instead of addition you need to use subtraction
c.add(Calendar.MONTH, -1);
Then you can call getter on the Calendar to acquire proper fields
int month = c.get(Calendar.MONTH) + 1; // beware of month indexing from zero
int year = c.get(Calendar.YEAR);

java.time
Using java.time framework built into Java 8:
import java.time.LocalDate;
LocalDate now = LocalDate.now(); // 2015-11-24
LocalDate earlier = now.minusMonths(1); // 2015-10-24
earlier.getMonth(); // java.time.Month = OCTOBER
earlier.getMonth.getValue(); // 10
earlier.getYear(); // 2015

Use Joda Time Library. It is very easy to handle date, time, calender and locale with it and it will be integrated to java in version 8.
DateTime#minusMonths method would help you get previous month.
DateTime month = new DateTime().minusMonths (1);

you can use the Calendar class to do so:
SimpleDateFormat format = new SimpleDateFormat("yyyy.MM.dd HH:mm");
Calendar cal = Calendar.getInstance();
cal.add(Calendar.MONTH, -1);
System.out.println(format.format(cal.getTime()));
This prints : 2012.09.10 11:01 for actual date 2012.10.10 11:01

The simplest & least error prone approach is... Use Calendar's roll() method. Like this:
c.roll(Calendar.MONTH, false);
the roll method takes a boolean, which basically means roll the month up(true) or down(false)?

YearMonth class
You can use the java.time.YearMonth class, and its minusMonths method.
YearMonth lastMonth = YearMonth.now().minusMonths(1);
Calling toString gives you output in standard ISO 8601 format: yyyy-mm
You can access the parts, the year and the month. You may choose to use the Month enum object, or a mere int value 1-12 for the month.
int year = lastMonth.getYear() ;
int month = lastMonth.getMonthValue() ;
Month monthEnum = lastMonth.getMonth() ;

private static String getPreviousMonthDate(Date date){
final SimpleDateFormat format = new SimpleDateFormat("dd-MM-yyyy");
Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.set(Calendar.DAY_OF_MONTH, 1);
cal.add(Calendar.DATE, -1);
Date preMonthDate = cal.getTime();
return format.format(preMonthDate);
}
private static String getPreToPreMonthDate(Date date){
final SimpleDateFormat format = new SimpleDateFormat("dd-MM-yyyy");
Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.add(Calendar.MONTH, -1);
cal.set(Calendar.DAY_OF_MONTH,1);
cal.add(Calendar.DATE, -1);
Date preToPreMonthDate = cal.getTime();
return format.format(preToPreMonthDate);
}

You need to be aware that month is zero based so when you do the getMonth you will need to add 1. In the example below we have to add 1 to Januaray as 1 and not 0
Calendar c = Calendar.getInstance();
c.set(2011, 2, 1);
c.add(Calendar.MONTH, -1);
int month = c.get(Calendar.MONTH) + 1;
assertEquals(1, month);

You get by using the LocalDate class.
For Example:
To get last month date:
LocalDate.now().minusMonths(1);
To get starting date of last month
LocalDate.now().minusMonths(1).with(TemporalAdjusters.firstDayOfMonth());
Similarly for Year:
To get last year date:
LocalDate.now().minusYears(1);
To get starting date of last year :
LocalDate.now().minusYears(1).with(TemporalAdjusters.lastDayOfYear());

Here's the code snippet.I think it works.
Calendar cal = Calendar.getInstance();
SimpleDateFormat simpleMonth=new SimpleDateFormat("MMMM YYYY");
cal.add(Calendar.MONTH, -1);
System.out.println(simpleMonth.format(prevcal.getTime()));

Find Missing Dates Between Two Dates

I got a list of dates as String
for example date1->'11-11-2010' and date2->'12-01-2011'
I want to print all the dates between these two dates..
I tried to work with cal.add() but am not able to set my date1 to my cal.. if i do so i get null p

below code should do the trick for you.
String date1 = "11-11-2010";
String date2 = "12-01-2011";
SimpleDateFormat format = new SimpleDateFormat("MM-dd-yyyy");
Calendar calendar1 = Calendar.getInstance();
calendar1.setTime(format.parse(date1));
Calendar calendar2 = Calendar.getInstance();
calendar2.setTime(format.parse(date2));
Date currentDate = calendar1.getTime();
while(!currentDate.equals(cal2.getTime())){
calendar1.add(Calendar.DAY_OF_MONTH, 1);
currentDate = cal1.getTime();
System.out.println(currentDate);
}