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I was trying to add current time into previous date. But it was adding in current date with time not with previous date.
see my bellow code:
Date startUserDate = ;//this is my previous date object;
startUserDate.setTime(new Date().getTime());// here i'm trying to add current time in previous date.
System.out.println("current time with previous Date :"+startUserDate);
In previous date there is no time and i want to add current time in previous date.I can do this, please help me out.
Use calendar object
Get instance of calendar object and set your past time to it
Date startUserDate = ;
Calendar calendar = Calendar.getInstance();
calendar.settime(startUserDate);
Create new calendar instance
Calendar cal = Calendar.getInstance();
cal.settime(new Date());
format the date to get string representation of time of current date
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
String currentdate = sdf.format(cal.getTime());
split that string to get hour minute and second object
String hh = expiry.split(":")[0];
String mm = expiry.split(":")[1];
String ss = expiry.split(":")[2];
add it to the previous calendar object
calendar .add(Calendar.HOUR_OF_DAY, hh);
calendar .add(Calendar.MINUTE, mm);
calendar .add(Calendar.SECOND, ss);
this date will have current time added to your date
Date newDate = calendar.getTime;
Use Calendar:
first set the date/time of the first calendar object to the old date
object use as second Calendar object to set the current time on the
first calendar object then convert it back to date
as follow:
//E.g. for startUserDate
Date startUserDate = new Date(System.currentTimeMillis() - (24L * 60L * 60L * 1000L) - (60L * 60L * 1000L));//minus 1 day and 1 hour
Calendar calDateThen = Calendar.getInstance();
Calendar calTimeNow = Calendar.getInstance();
calDateThen.setTime(startUserDate);
calDateThen.set(Calendar.HOUR_OF_DAY, calTimeNow.get(Calendar.HOUR_OF_DAY));
calDateThen.set(Calendar.MINUTE, calTimeNow.get(Calendar.MINUTE));
calDateThen.set(Calendar.SECOND, calTimeNow.get(Calendar.SECOND));
startUserDate = calDateThen.getTime();
System.out.println(startUserDate);
The second Calendar object calTimeNow can be replaced with Calendar.getInstance() where it is used.
You can do it using DateFormat and String, here's the solution that you need:
Code:
DateFormat df = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
String timeString = df.format(new Date()).substring(10); // 10 is the beginIndex of time here
DateFormat df2 = new SimpleDateFormat("MM/dd/yyyy");
String startUserDateString = df2.format(startUserDate);
startUserDateString = startUserDateString+" "+timeString;
// you will get this format "MM/dd/yyyy HH:mm:ss"
//then parse the new date here
startUserDate = df.parse(startUserDateString);
Explanation:
Just convert the current date to a string and then extract the time from it using .substring() method, then convert your userDate to a string concatenate the taken time String to it and finally parse this date to get what you need.
Example:
You can see it working in this ideone DEMO.
Which takes 02/20/2002 in input and returns 02/20/2002 04:36:14 as result.
java.time
I recommend that you use java.time, the modern Java date and time API, for your date and time work.
ZoneId zone = ZoneId.systemDefault();
LocalDate somePreviousDate = LocalDate.of(2018, Month.NOVEMBER, 22);
LocalTime timeOfDayNow = LocalTime.now(zone);
LocalDateTime dateTime = somePreviousDate.atTime(timeOfDayNow);
System.out.println(dateTime);
When I ran the code just now — 16:25 in my time zone — I got this output:
2018-11-22T16:25:53.253892
If you’ve got an old-fashioned Date object, start by converting to a modern Instant and perform further conversion from there:
Date somePreviousDate = new Date(1_555_555_555_555L);
LocalDate date = somePreviousDate.toInstant().atZone(zone).toLocalDate();
LocalTime timeOfDayNow = LocalTime.now(zone);
LocalDateTime dateTime = date.atTime(timeOfDayNow);
2019-04-18T16:25:53.277947
If conversely you need the result as an old-fashioned Date, also convert over Instant:
Instant i = dateTime.atZone(zone).toInstant();
Date oldfasionedDate = Date.from(i);
System.out.println(oldfasionedDate);
Thu Nov 22 16:25:53 CET 2018
Link
Oracle tutorial: Date Time explaining how to use java.time.
The getTime method returns the number of milliseconds since 1970/01/01 so to get the time portion of the date you can either use a Calendar object or simply use modula arithmetic (using the above milliseconds value and the MAX millseconds in a day) to extract the time portion of the Date.
Then when you have the time you need to add it to the second date,
but seriously, use http://docs.oracle.com/javase/7/docs/api/java/util/Calendar.html
and use things like get (HOUR) and get (MINUTE) etc. which then you can use with set (HOUR, val)
You need to use Calendar class to perform addition to Dateobject. Date's setTime() will set that time in Date object but not add i.e it will overwrite previous date. new Date().getTime() will not return only time portion but time since Epoch. Also, how did you manipulated , startUserDate to not have any time (I mean , was it via Calendar or Formatter) ?
See Answer , Time Portion of Date to calculate only time portion,
long MILLIS_PER_DAY = 24 * 60 * 60 * 1000;
Date now = Calendar.getInstance().getTime();
long timePortion = now.getTime() % MILLIS_PER_DAY;
then you can use something like, cal.add(Calendar.MILLISECOND, (int)timePortion); where cal is Calendar object corresponding to your startUserDate in your code.
Calendar calendar = Calendar.getInstance();
calendar.setTime(startUserDate );
//new date for current time
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
String currentdate = sdf.format(new Date());
String hhStr = currentdate.split(":")[0];
String mmStr = currentdate.split(":")[1];
String ssStr = currentdate.split(":")[2];
Integer hh = 0;
Integer mm = 0;
Integer ss = 0;
try {
hh = Integer.parseInt(hhStr);
mm = Integer.parseInt(mmStr);
ss = Integer.parseInt(ssStr);
}catch(Exception e) {e.printStackTrace();}
calendar.set(Calendar.HOUR_OF_DAY, hh);
calendar.set(Calendar.MINUTE, mm);
calendar.set(Calendar.SECOND, ss);
startUserDate = calendar.getTime();
Good day, quick question, Am trying to compare if 2 dates are the same day for the same time zone (city)Anyone have any idea why the following code holds and the other doesn't, can't seem to understand why.
SimpleDateFormat fmt = new SimpleDateFormat("EEE dd,MMM");
Date newparsetemp = fmt.parse(parsedate);
Date currentdateparse = fmt.parse(currentdate);
if(currentdateparse.equals(newparsetemp)){
//code executes
}
but if i do use this, the if condition doesn't hold
SimpleDateFormat fmt = new SimpleDateFormat("yyyyMMdd");
Date newparsetemp = fmt.parse(parsedate);
Date currentdateparse = fmt.parse(currentdate);
if(currentdateparse.equals(newparsetemp)){
//does not
}
Consider using Joda-Time's LocalDate.
Date data1 = ...
Date date2 = ...
new LocalDate(date1).equals(new LocalDate(date2))
Better yet just skip Date and use LocalDate instead.
Comparing after formatting to a string is an odd thing to do. Try this instead:
Calendar cal = GregorianCalendar.getInstance();
cal.setTime(parsedate);
Calendar cal2 = GregorianCalendar.getInstance();
cal2.setTime(currentdate);
cal2.set(Calendar.HOUR, 0);
cal2.set(Calendar.MINUTE, 0);
cal2.set(Calendar.SECOND, 0);
cal2.set(Calendar.MILLISECOND, 0);
cal.set(Calendar.HOUR, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);
System.out.println(cal.equals(cal2) ? "true" : "false");
Your comment about timezones needs clarification. Did you mean to say
compare if 2 dates are the same day for different time zones?
If you mean "comparing only the day of week", have you tried comparing the result of Calendar.get(Calendar.DAY_OF_WEEK) instead?
do you agree that there is a chance that two different dates from different years, in the same month and day, can match the same day of the week?
and that there's no chance of two different dates match the same day, month and year?
I've actually done this not too long ago in one of my Android apps,
public boolean isSameDay(Event otherEvent) {
if(otherEvent == null) return false;
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm");
try {
Calendar otherEventDate = Calendar.getInstance();
otherEventDate.setTime(format.parse(otherEvent.getStartTime()));
Calendar thisEventDate = Calendar.getInstance();
thisEventDate.setTime(format.parse(getStartTime()));
return (otherEventDate.get(Calendar.DAY_OF_MONTH) == thisEventDate.get(Calendar.DAY_OF_MONTH) &&
otherEventDate.get(Calendar.DAY_OF_YEAR) == thisEventDate.get(Calendar.DAY_OF_YEAR));
} catch(ParseException e) {
System.out.println(e.toString());
e.printStackTrace();
}
return false;
}
Here's the code as I did it, I'm just checking if the two events are occurring the same day. If you wish to add some more precision you'll just have to add this for yourself.
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?
Java 8 and later
With Java 8's date time API change, Use LocalDate
LocalDate date = LocalDate.now().minusDays(300);
Similarly you can have
LocalDate date = someLocalDateInstance.minusDays(300);
Refer to https://stackoverflow.com/a/23885950/260990 for translation between java.util.Date <--> java.time.LocalDateTime
Date in = new Date();
LocalDateTime ldt = LocalDateTime.ofInstant(in.toInstant(), ZoneId.systemDefault());
Date out = Date.from(ldt.atZone(ZoneId.systemDefault()).toInstant());
Java 7 and earlier
Use Calendar's add() method
Calendar cal = Calendar.getInstance();
cal.setTime(dateInstance);
cal.add(Calendar.DATE, -30);
Date dateBefore30Days = cal.getTime();
#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);
Simply use this to get date before 300 days, replace 300 with your days:
Date date = new Date(); // Or where ever you get it from
Date daysAgo = new DateTime(date).minusDays(300).toDate();
Here,
DateTime is org.joda.time.DateTime;
Date is java.util.Date
Java 8 Time API:
Instant now = Instant.now(); //current date
Instant before = now.minus(Duration.ofDays(300));
Date dateBefore = Date.from(before);
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
*/
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.
In Java 8 you can do this:
Instant inst = Instant.parse("2018-12-30T19:34:50.63Z");
// subtract 10 Days to Instant
Instant value = inst.minus(Period.ofDays(10));
// print result
System.out.println("Instant after subtracting Days: " + value);
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 may also be able to use the Duration class. E.g.
Date currentDate = new Date();
Date oneDayFromCurrentDate = new Date(currentDate.getTime() - Duration.ofDays(1).toMillis());
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;
}
I want to get the Date in MM/DD/YY format from a timestamp.
I have used the below method but it does not gives proper output
final Calendar cal = Calendar.getInstance();
cal.setTimeInMillis(Long.parseLong(1306249409));
Log.d("Date--",""+cal.DAY_OF_MONTH);
Log.d("Month--",""+cal.MONTH);
Log.d("Year--",""+cal.YEAR);
But its gives the output like below
Date--5
Month--2
Year--1
The correct date is 24 May 2010 for Timestamp - 1306249409
Note - Timestamp is received by a webservice which is used in my application.
Better Approach
Simply Use SimpleDateFormat
new SimpleDateFormat("MM/dd/yyyy").format(new Date(timeStampMillisInLong));
Mistake in your Approach
DAY_OF_MONTH ,MONTH, .. etc are just constant int value used by Calendar class
internally
You can get the date represented by cal by cal.get(Calendar.DATE)
Use the SimpleDateFormat
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date date = new Date();
String time = sdf.format(date);
What's wrong:
Calendar.DAY_OF_MONTH, Calendar.MONTH etc are static constants used to access those particular fields. (They will remain constant, no matter what setTimeInMillis you provide.)
How to solve it:
To get those particular fields you can use the .get(int field)-method, like this:
Log.d("Month--",""+cal.get(Calendar.MONTH));
As others have pointed out there are more convenient methods for formatting a date for logging. You could use for instance the SimpleDateFormat, or, as I usually do when logging, a format-string and String.format(formatStr, Calendar.getInstance()).
Date date = new Date(System.currentTimeMillis());
SimpleDateFormat formatter = new SimpleDateFormat("MM/dd/yy");
String s = formatter.format(date);
System.out.println(s);
TimeZone utc = TimeZone.getTimeZone("UTC"); // avoiding local time zone overhead
final Calendar cal = new GregorianCalendar(utc);
// always use GregorianCalendar explicitly if you don't want be suprised with
// Japanese Imperial Calendar or something
cal.setTimeInMillis(1306249409L*1000); // input need to be in miliseconds
Log.d("Date--",""+cal.get(Calendar.DAY_OF_MONTH));
Log.d("Month--",""+cal.get(Calendar.MONTH) + 1); // it starts from zero, add 1
Log.d("Year--",""+cal.get(Calendar.YEAR));
Java uses the number of milliseconds since 1st January 1970 to represent times. If you compute the time represented by 1306249409 milliseconds, you'll discover that it's only 362 days, so your assumptions are wrong.
Moreover, cal.DAY_OF_MONTH holds a constant. Use cal.get(Calendar.DAY_OF_MONTH) to get the day of month (same for other parts of the date).
use String.format which is able to convert long (milliseconds) to date/time string in different formats:
String str;
long time = 1306249409 * 1000L; // milliseconds
str = String.format("%1$tm/%1$td/%1$ty", time); // 05/24/11
str = String.format("%tF", time); // 2011-05-24 (ISO 8601)
str = String.format("Date--%td", time); // Date--24
str = String.format("Month--%tm", time); // Month--05
str = String.format("Year--%ty", time); // Year--11
documentation: format string.
I have a String Object in format yyyyMMdd.Is there a simple way to get a String with previous date in the same format?
Thanks
I would rewrite these answers a bit.
You can use
DateFormat dateFormat = new SimpleDateFormat("yyyyMMdd");
// Get a Date object from the date string
Date myDate = dateFormat.parse(dateString);
// this calculation may skip a day (Standard-to-Daylight switch)...
//oneDayBefore = new Date(myDate.getTime() - (24 * 3600000));
// if the Date->time xform always places the time as YYYYMMDD 00:00:00
// this will be safer.
oneDayBefore = new Date(myDate.getTime() - 2);
String result = dateFormat.format(oneDayBefore);
To get the same results as those that are being computed by using Calendar.
Here is how to do it without Joda Time:
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class Main {
public static String previousDateString(String dateString)
throws ParseException {
// Create a date formatter using your format string
DateFormat dateFormat = new SimpleDateFormat("yyyyMMdd");
// Parse the given date string into a Date object.
// Note: This can throw a ParseException.
Date myDate = dateFormat.parse(dateString);
// Use the Calendar class to subtract one day
Calendar calendar = Calendar.getInstance();
calendar.setTime(myDate);
calendar.add(Calendar.DAY_OF_YEAR, -1);
// Use the date formatter to produce a formatted date string
Date previousDate = calendar.getTime();
String result = dateFormat.format(previousDate);
return result;
}
public static void main(String[] args) {
String dateString = "20100316";
try {
// This will print 20100315
System.out.println(previousDateString(dateString));
} catch (ParseException e) {
System.out.println("Invalid date string");
e.printStackTrace();
}
}
}
You can use:
Calendar cal = Calendar.getInstance();
//subtracting a day
cal.add(Calendar.DATE, -1);
SimpleDateFormat s = new SimpleDateFormat("yyyyMMdd");
String result = s.format(new Date(cal.getTimeInMillis()));
It's much harder than it should be in Java without library support.
You can parse the given String into a Date object using an instance of the SimpleDateFormat class.
Then you can use Calendar's add() to subtract one day.
Then you can use SimpleDateFormat's format() to get the formatted date as a String.
The Joda Time library a much easier API.
This is an old question, and most existing answers pre-date Java 8. Hence, adding this answer for Java 8+ users.
Java 8 introduced new APIs for Date and Time to replace poorly designed, and difficult to use java.util.Date and java.util.Calendar classes.
To deal with dates without time zones, LocalDate class can be used.
String dateString = "20200301";
// BASIC_ISO_DATE is "YYYYMMDD"
// See below link to docs for details
LocalDate date = LocalDate.parse(dateString, DateTimeFormatter.BASIC_ISO_DATE);
// get date for previous day
LocalDate previousDate = date.minusDays(1);
System.out.println(previousDate.format(DateTimeFormatter.BASIC_ISO_DATE));
// prints 20200229
Docs:
DateTimeFormatter.BASIC_ISO_DATE
LocalDate
use SimpleDateFormat to parse the String to Date, then subtract one day. after that convert the date to String again.
HI,
I want to get 20 days previous, to current date,
Calendar cal = Calendar.getInstance();
Calendar xdate = (Calendar)cal.clone();
xdate.set(Calendar.DAY_OF_YEAR, - 20);
System.out.println(" Current Time "+ cal.getTime().toString());
System.out.println(" X Time "+ xdate.getTime().toString());
I had some UN Expected result, When i tried on Jan 11th,
Current Time Tue Jan 11 12:32:16 IST 2011
X Time Sat Dec 11 12:32:16 IST 2010
Calendar cal = Calendar.getInstance();
Calendar xdate = (Calendar)cal.clone();
xdate.set(Calendar.DAY_OF_YEAR,cal.getTime().getDate() - 20 );
System.out.println(" Current Time "+ cal.getTime().toString());
System.out.println(" X Time "+ xdate.getTime().toString());
This code solved my Problem.
If you are willing to use the 3rd-party utility, Joda-Time, here is some example code using Joda-Time 2.3 on Java 7. Takes just two lines.
String dateAsString = "20130101";
org.joda.time.LocalDate someDay = org.joda.time.LocalDate.parse(dateAsString, org.joda.time.format.DateTimeFormat.forPattern("yyyymmdd"));
org.joda.time.LocalDate dayBefore = someDay.minusDays(1);
See the results:
System.out.println("someDay: " + someDay );
System.out.println("dayBefore: " + dayBefore );
When run:
someDay: 2013-01-01
dayBefore: 2012-12-31
This code assumes you have no time zone. Lacking a time zone is rarely a good thing, but if that's your case, that code may work for you. If you do have a time zone, use a DateTime object instead of LocalDate.
About that example code and about Joda-Time…
// © 2013 Basil Bourque. This source code may be used freely forever by anyone taking full responsibility for doing so.
// Joda-Time - The popular alternative to Sun/Oracle's notoriously bad date, time, and calendar classes bundled with Java 7 and earlier.
// http://www.joda.org/joda-time/
// Joda-Time will become outmoded by the JSR 310 Date and Time API introduced in Java 8.
// JSR 310 was inspired by Joda-Time but is not directly based on it.
// http://jcp.org/en/jsr/detail?id=310
// By default, Joda-Time produces strings in the standard ISO 8601 format.
// https://en.wikipedia.org/wiki/ISO_8601
you can create a generic method which takes
- Date (String) (current date or from date),
- Format (String) (your desired fromat) and
- Days (number of days before(-ve value) or after(+ve value))
as input and return your desired date in required format.
following method can resolve this problem.
public String getRequiredDate(String date , String format ,int days){
try{
final Calendar cal = Calendar.getInstance();
cal.setTime(new SimpleDateFormat(format).parse(date));
cal.add(Calendar.DATE, days);
SimpleDateFormat sdf = new SimpleDateFormat(format);
date = sdf.format(cal.getTime());
}
catch(Exception ex){
logger.error(ex.getMessage(), ex);
}
return date;
}
}
In Java 8 we can use directly for this purpose
LocalDate todayDate = LocalDate.now();
By default it provide the format of 2021-06-07, with the help of formater we can change this also
LocalDate previousDate = todayDate.minusDays(5);
Calendar cal2 = Calendar.getInstance();
cal2.add(Calendar.YEAR, -1);
Date dt2 = new Date(cal2.getTimeInMillis());
System.out.println(dt2);