How to Check If a Date Object Equals Yesterday

How to check if a date Object equals yesterday?

Calendar c1 = Calendar.getInstance(); // today
c1.add(Calendar.DAY_OF_YEAR, -1); // yesterday

Calendar c2 = Calendar.getInstance();
c2.setTime(getDateFromLine(line)); // your date

if (c1.get(Calendar.YEAR) == c2.get(Calendar.YEAR)
  && c1.get(Calendar.DAY_OF_YEAR) == c2.get(Calendar.DAY_OF_YEAR)) {

This will also work for dates like 1st of January.

Get yesterday's date using Date

Update

There has been recent improvements in datetime API with JSR-310.

Instant now = Instant.now();
Instant yesterday = now.minus(1, ChronoUnit.DAYS);
System.out.println(now);
System.out.println(yesterday);

https://ideone.com/91M1eU

Outdated answer

You are subtracting the wrong number:

Use Calendar instead:

private Date yesterday() {
    final Calendar cal = Calendar.getInstance();
    cal.add(Calendar.DATE, -1);
    return cal.getTime();
}

Then, modify your method to the following:

private String getYesterdayDateString() {
        DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
        return dateFormat.format(yesterday());
}

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See

• IDEOne Demo

Elegantly check if a given date is yesterday

PHP:

$isYesterday = date('Ymd', $timestamp) == date('Ymd', strtotime('yesterday'));

Calculate the date yesterday in JavaScript

var date = new Date();

date ; //# => Fri Apr 01 2011 11:14:50 GMT+0200 (CEST)

date.setDate(date.getDate() - 1);

date ; //# => Thu Mar 31 2011 11:14:50 GMT+0200 (CEST)

check if datetime variable is today, tomorrow or yesterday

final now = DateTime.now();
final today = DateTime(now.year, now.month, now.day);
final yesterday = DateTime(now.year, now.month, now.day - 1);
final tomorrow = DateTime(now.year, now.month, now.day + 1);

final dateToCheck = ...
final aDate = DateTime(dateToCheck.year, dateToCheck.month, dateToCheck.day);
if(aDate == today) {
  ...
} else if(aDate == yesterday) {
  ...
} else(aDate == tomorrow) {
  ...
}

Hit: now.day - 1 and now.day + 1 works well with dates that result in a different year or month.

How to set a Java Date object's value to yesterday?

Do you mean to go back 24 hours in time.

 Date date = new Date(System.currentTimeMillis() - 24 * 60 * 60 * 1000L);

or to go back one day at the time same time (this can be 23 or 25 hours depending on daylight savings)

 Calendar cal = Calendar.getInstance();
 cal.add(Calendar.DATE, -1); 

These are not exactly the same due to daylight saving.

moment.js - test if a date is today, yesterday, within a week or two weeks ago

Here's something that can be useful:

var REFERENCE = moment("2015-06-05"); // fixed just for testing, use moment();
var TODAY = REFERENCE.clone().startOf('day');
var YESTERDAY = REFERENCE.clone().subtract(1, 'days').startOf('day');
var A_WEEK_OLD = REFERENCE.clone().subtract(7, 'days').startOf('day');

function isToday(momentDate) {
    return momentDate.isSame(TODAY, 'd');
}
function isYesterday(momentDate) {
    return momentDate.isSame(YESTERDAY, 'd');
}
function isWithinAWeek(momentDate) {
    return momentDate.isAfter(A_WEEK_OLD);
}
function isTwoWeeksOrMore(momentDate) {
    return !isWithinAWeek(momentDate);
}

console.log("is it today? ..................Should be true: "+isToday(moment("2015-06-05")));
console.log("is it yesterday? ..............Should be true: "+isYesterday(moment("2015-06-04")));
console.log("is it within a week? ..........Should be true: "+isWithinAWeek(moment("2015-06-03")));
console.log("is it within a week? ..........Should be false: "+isWithinAWeek(moment("2015-05-29")));
console.log("is it two weeks older or more? Should be false: "+isTwoWeeksOrMore(moment("2015-05-30")));
console.log("is it two weeks older or more? Should be true: "+isTwoWeeksOrMore(moment("2015-05-29")));

Check a JSFiddle demo with more tests, so you can tweak for your exact case, if needed.

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