[java] How to compare dates in Java?

How do I compare dates in between in Java?

Example:

date1 is 22-02-2010
date2 is 07-04-2010 today
date3 is 25-12-2010

date3 is always greater than date1 and date2 is always today. How do I verify if today's date is in between date1 and date 3?

Compare the two dates:

  Date today = new Date();                   
  Date myDate = new Date(today.getYear(),today.getMonth()-1,today.getDay());
  System.out.println("My Date is"+myDate);    
  System.out.println("Today Date is"+today);
  if (today.compareTo(myDate)<0)
      System.out.println("Today Date is Lesser than my Date");
  else if (today.compareTo(myDate)>0)
      System.out.println("Today Date is Greater than my date"); 
  else
      System.out.println("Both Dates are equal"); 

Use getTime() to get the numeric value of the date, and then compare using the returned values.

tl;dr

LocalDate today = LocalDate.now( ZoneId.of( "America/Montreal" ) ) ;
Boolean isBetween = 
    ( ! today.isBefore( localDate1 ) )  // “not-before” is short for “is-equal-to or later-than”.
    &&
    today.isBefore( localDate3 ) ; 

Or, better, if you add the ThreeTen-Extra library to your project.

LocalDateRange.of(
    LocalDate.of( … ) ,
    LocalDate.of( … )
).contains(
    LocalDate.now()
)

Half-open approach, where beginning is inclusive while ending is exclusive.

Bad Choice of Format

By the way, that is a bad choice of format for a text representation of a date or date-time value. Whenever possible, stick with the standard ISO 8601 formats. ISO 8601 formats are unambiguous, understandable across human cultures, and are easy to parse by machine.

For a date-only value, the standard format is YYYY-MM-DD. Note how this format has the benefit of being chronological when sorted alphabetically.

LocalDate

The LocalDate class represents a date-only value without time-of-day and without time zone.

A time zone is crucial in determining a date. For any given moment, the date varies around the globe by zone. For example, a few minutes after midnight in Paris France is a new day while still “yesterday” in Montréal Québec.

ZoneId z = ZoneId.of( "America/Montreal" );
LocalDate today = LocalDate.now( z );

DateTimeFormatter

As your input strings are non-standard format, we must define a formatting pattern to match.

DateTimeFormatter f = DateTimeFormatter.ofPattern( "dd-MM-uuuu" );

Use that to parse the input strings.

LocalDate start = LocalDate.parse( "22-02-2010" , f );
LocalDate stop = LocalDate.parse( "25-12-2010" , f );

In date-time work, usually best to define a span of time by the Half-Open approach where the beginning is inclusive while the ending is exclusive. So we want to know if today is the same or later than the start and also before the stop. A briefer way of saying “is the same or later than the start” is “not before the start”.

Boolean intervalContainsToday = ( ! today.isBefore( start ) ) && today.isBefore( stop ) ;

See the Answer by gstackoverflow showing the list of comparison methods you can call.

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes. Hibernate 5 & JPA 2.2 support java.time.

Where to obtain the java.time classes?

• Java SE 8, Java SE 9, Java SE 10, Java SE 11, and later - Part of the standard Java API with a bundled implementation.
  • Java 9 brought some minor features and fixes.
• Java SE 6 and Java SE 7
  • Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
• Android
  • Later versions of Android (26+) bundle implementations of the java.time classes.
  • For earlier Android (<26), a process known as API desugaring brings a subset of the java.time functionality not originally built into Android.
    • If the desugaring does not offer what you need, the ThreeTenABP project adapts ThreeTen-Backport (mentioned above) to Android. See How to use ThreeTenABP….

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

UPDATE: This “Joda-Time” section below is left intact as history. The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

Joda-Time

Other answers are correct with regard to the bundled java.util.Date and java.util.Calendar classes. But those classes are notoriously troublesome. So here's some example code using the Joda-Time 2.3 library.

If you truly want a date without any time portion and no time zone, then use the LocalDate class in Joda-Time. That class provides methods of comparison including compareTo (used with Java Comparators), isBefore, isAfter, and isEqual.

Inputs…

String string1 = "22-02-2010";
String string2 = "07-04-2010";
String string3 = "25-12-2010";

Define a formatter describing the input strings…

DateTimeFormatter formatter = DateTimeFormat.forPattern( "dd-MM-yyyy" );

Use formatter to parse the strings into LocalDate objects…

LocalDate localDate1 = formatter.parseLocalDate( string1 );
LocalDate localDate2 = formatter.parseLocalDate( string2 );
LocalDate localDate3 = formatter.parseLocalDate( string3 );

boolean is1After2 = localDate1.isAfter( localDate2 );
boolean is2Before3 = localDate2.isBefore( localDate3 );

Dump to console…

System.out.println( "Dates: " + localDate1 + " " + localDate2 + " " + localDate3 );
System.out.println( "is1After2 " + is1After2 );
System.out.println( "is2Before3 " + is2Before3 );

When run…

Dates: 2010-02-22 2010-04-07 2010-12-25
is1After2 false
is2Before3 true

So see if the second is between the other two (exclusively, meaning not equal to either endpoint)…

boolean is2Between1And3 = ( ( localDate2.isAfter( localDate1 ) ) && ( localDate2.isBefore( localDate3 ) ) );

Working With Spans Of Time

If you are working with spans of time, I suggest exploring in Joda-Time the classes: Duration, Interval, and Period. Methods such as overlap and contains make comparisons easy.

For text representations, look at the ISO 8601 standard’s:

• duration
  Format: PnYnMnDTnHnMnS
  Example: P3Y6M4DT12H30M5S
  (Means “three years, six months, four days, twelve hours, thirty minutes, and five seconds”)
• interval
  Format: start/end
  Example: 2007-03-01T13:00:00Z/2008-05-11T15:30:00Z

Joda-Time classes can work with strings in both those formats, both as input (parsing) and output (generating strings).

Joda-Time performs comparisons using the Half-Open approach where the beginning of the span is inclusive while the ending is exclusive. This approach is a wise one for handling spans of time. Search StackOverflow for more info.

Update for Java 8 and later

• isAfter()
• isBefore()
• isEqual()
• compareTo()

These methods exists in LocalDate, LocalTime, and LocalDateTime classes.

Those classes are built into Java 8 and later. Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport and further adapted to Android in ThreeTenABP (see How to use…).

Try this

public static boolean compareDates(String psDate1, String psDate2) throws ParseException{
        SimpleDateFormat dateFormat = new SimpleDateFormat ("dd/MM/yyyy");
        Date date1 = dateFormat.parse(psDate1);
        Date date2 = dateFormat.parse(psDate2);
        if(date2.after(date1)) {
            return true;
        } else {
            return false;
        }
    }

You can use Date.getTime() which:

Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object.

This means you can compare them just like numbers:

if (date1.getTime() <= date.getTime() && date.getTime() <= date2.getTime()) {
    /*
     * date is between date1 and date2 (both inclusive)
     */
}

/*
 * when date1 = 2015-01-01 and date2 = 2015-01-10 then
 * returns true for:
 * 2015-01-01
 * 2015-01-01 00:00:01
 * 2015-01-02
 * 2015-01-10
 * returns false for:
 * 2014-12-31 23:59:59
 * 2015-01-10 00:00:01
 * 
 * if one or both dates are exclusive then change <= to <
 */

Use compareTo:

date1.compareTo(date2);

Following are most common way of comparing dates (my preference is Approach 1):

Approach 1: Using Date.before(), Date.after() and Date.equals()

if (date1.after(date2)) {
    System.out.println("Date1 is after Date2");
}

if (date1.before(date2)) {
    System.out.println("Date1 is before Date2");
}

if (date1.equals(date2)) {
    System.out.println("Date1 is equal Date2");
}

Approach 2: Date.compareTo()

if (date1.compareTo(date2) > 0) {
    System.out.println("Date1 is after Date2");
} else if (date1.compareTo(date2) < 0) {
    System.out.println("Date1 is before Date2");
} else {
    System.out.println("Date1 is equal to Date2");
}

Approach 3: Calender.before(), Calender.after() and Calender.equals()

Calendar cal1 = Calendar.getInstance();
Calendar cal2 = Calendar.getInstance();
cal1.setTime(date1);
cal2.setTime(date2);

if (cal1.after(cal2)) {
    System.out.println("Date1 is after Date2");
}

if (cal1.before(cal2)) {
    System.out.println("Date1 is before Date2");
}

if (cal1.equals(cal2)) {
    System.out.println("Date1 is equal Date2");
}

This code determine today is in some duration.. based on KOREA locale

    Calendar cstart = Calendar.getInstance(Locale.KOREA);
    cstart.clear();
    cstart.set(startyear, startmonth, startday);


    Calendar cend = Calendar.getInstance(Locale.KOREA);
    cend.clear();
    cend.set(endyear, endmonth, endday);

    Calendar c = Calendar.getInstance(Locale.KOREA);

    if(c.after(cstart) && c.before(cend)) {
        // today is in startyear/startmonth/startday ~ endyear/endmonth/endday
    }

This method worked for me:

 public static String daysBetween(String day1, String day2) {
    String daysBetween = "";
    SimpleDateFormat myFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    try {
        Date date1 = myFormat.parse(day1);
        Date date2 = myFormat.parse(day2);
        long diff = date2.getTime() - date1.getTime();
        daysBetween = ""+(TimeUnit.DAYS.convert(diff, TimeUnit.MILLISECONDS));
    } catch (ParseException e) {
        e.printStackTrace();
    }
    return daysBetween;
}