Comparing Date in Java

import java.text.DateFormat;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Calendar;

import java.util.Date;

public class HashtableDemo {

    public static void main(String args[]) throws AssertionError, ParseException {

        DateFormat df = new SimpleDateFormat("dd-MM-yyyy");

        //comparing date using compareTo method in Java

        System.out.println("Comparing two Date in Java using CompareTo method");

        compareDatesByCompareTo(df, df.parse("01-01-2012"), df.parse("01-01-2012"));

        compareDatesByCompareTo(df, df.parse("02-03-2012"), df.parse("04-05-2012"));

        compareDatesByCompareTo(df, df.parse("02-03-2012"), df.parse("01-02-2012"));

        //comparing dates in java using Date.before, Date.after and Date.equals

        System.out.println("Comparing two Date in Java using Date's before, after and equals method");

        compareDatesByDateMethods(df, df.parse("01-01-2012"), df.parse("01-01-2012"));

        compareDatesByDateMethods(df, df.parse("02-03-2012"), df.parse("04-05-2012"));

        compareDatesByDateMethods(df, df.parse("02-03-2012"), df.parse("01-02-2012"));

        //comparing dates in java using Calendar.before(), Calendar.after and Calendar.equals()

        System.out.println("Comparing two Date in Java using Calendar's before, after and equals method");

        compareDatesByCalendarMethods(df, df.parse("01-01-2012"), df.parse("01-01-2012"));

        compareDatesByCalendarMethods(df, df.parse("02-03-2012"), df.parse("04-05-2012"));

        compareDatesByCalendarMethods(df, df.parse("02-03-2012"), df.parse("01-02-2012"));

    }

    public static void compareDatesByCompareTo(DateFormat df, Date oldDate, Date newDate) {

        //how to check if date1 is equal to date2

        if (oldDate.compareTo(newDate) == 0) {

            System.out.println(df.format(oldDate) + " and " + df.format(newDate) + " are equal to each other");

        }

        //checking if date1 is less than date 2

        if (oldDate.compareTo(newDate) < 0) {

            System.out.println(df.format(oldDate) + " is less than " + df.format(newDate));

        }

        //how to check if date1 is greater than date2 in java

        if (oldDate.compareTo(newDate) > 0) {

            System.out.println(df.format(oldDate) + " is greater than " + df.format(newDate));

        }

    }

    public static void compareDatesByDateMethods(DateFormat df, Date oldDate, Date newDate) {

        //how to check if two dates are equals in java

        if (oldDate.equals(newDate)) {

            System.out.println(df.format(oldDate) + " and " + df.format(newDate) + " are equal to each other");

        }

        //checking if date1 comes before date2

        if (oldDate.before(newDate)) {

            System.out.println(df.format(oldDate) + " comes before " + df.format(newDate));

        }

        //checking if date1 comes after date2

        if (oldDate.after(newDate)) {

            System.out.println(df.format(oldDate) + " comes after " + df.format(newDate));

        }

    }

    public static void compareDatesByCalendarMethods(DateFormat df, Date oldDate, Date newDate) {

        //creating calendar instances for date comparision

        Calendar oldCal = Calendar.getInstance();

        Calendar newCal = Calendar.getInstance();

        oldCal.setTime(oldDate);

        newCal.setTime(newDate);

        //how to check if two dates are equals in java using Calendar

        if (oldCal.equals(newCal)) {

            System.out.println(df.format(oldDate) + " and " + df.format(newDate) + " are equal to each other");

        }

        //how to check if one date comes before another using Calendar

        if (oldCal.before(newCal)) {

            System.out.println(df.format(oldDate) + " comes before " + df.format(newDate));

        }

        //how to check if one date comes after another using Calendar

        if (oldCal.after(newCal)) {

            System.out.println(df.format(oldDate) + " comes after " + df.format(newDate));

        }

    }

}

Output:

Comparing two Date in Java using CompareTo method
01-01-2012 and 01-01-2012 are equal to each other
02-03-2012 is less than 04-05-2012
02-03-2012 is greater than 01-02-2012
Comparing two Date in Java using Date's before, after and equals method
01-01-2012 and 01-01-2012 are equal to each other
02-03-2012 comes before 04-05-2012
02-03-2012 comes after 01-02-2012
Comparing two Date in Java using Calendar's before, after and equals method
01-01-2012 and 01-01-2012 are equal to each other
02-03-2012 comes before 04-05-2012
02-03-2012 comes after 01-02-2012

Source: roseIndia.net

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