Following are some important date class methods :
- .toString() : java.util.Date.tostring() method is a java.util.Date class method.It displays the Current date and time.
Here Date object is converted to a string and represented as:day mon dd hh:mm:ss zz yyyy
day : day of the week
mon : month
dd : day of the month
hh : hour
mm : minute
ss : second
zz : time zone
yyyy : year upto 4 decimal placesSyntax: public String toString() Return: a string representation of the given date.
- .setTime() : java.util.Date.setTime() method is a java.util.Date class method. Sets this Date object to represent a point in time that is time milliseconds after January 1, 1970 00:00:00 GMT.
Syntax: public void setTime(long time) Parameters: time : the number of milliseconds.
- .hashCode() : java.util.Date.hashCode() method is a java.util.Date class method. Returns a hash code value for the Date object. The result is exclusive OR of the two halves of the primitive long value returned by the getTime() method.
Syntax: public int hashCode() Return: a hash code value for the Date object.
Java Code to illustrate the use of .toString(), setTime(), hashCode() methods.
// Java Program explaining util.date class methods//
// use of .toString(), setTime(), hashCode() methods
import
java.util.*;
// class having access to Date class methods
public
class
NewClass
{
public
static
void
main(String[] args)
{
Date mydate =
new
Date();
// Displaying the current date and time
System.out.println(
"System date : "
+ mydate.toString() );
// Is used to set time by milliseconds. Adds 15680
// milliseconds to January 1, 1970 to get new time.
mydate.setTime(
15680
);
System.out.println(
"Time after setting: "
+ mydate.toString());
int
d = mydate.hashCode();
System.out.println(
"Amount (in ms) by which time"
+
" is shifted : "
+ d);
}
}
Output of Java code:
System date : Tue Nov 01 02:37:18 IST 2016 Time after setting: Thu Jan 01 05:30:15 IST 1970 Amount (in miliseconds) by which time is shifted : 15680
- .after() : java.util.Date.after() method tests if current date is after the given date.
Syntax: public boolean after(Date d) Parameters: d : date Return: true if and only if the instant represented by this Date object is strictly later than the instant represented by 'when'; else false Exception: NullPointerException - if Date object is null.
- .clone() : java.util.Date.clone() method returns the duplicate of passed Date object.
Syntax: public Object clone() Return: a clone of this instance.
- .before() : java.util.Date.after() method tests if current date is before the given date.
Syntax: public boolean before(Date d) Parameters: d : date Return: true if and only if the instant represented by this Date object is strictly earlier than the instant represented by 'when'; else false Exception: NullPointerException - if when is null.
Java Code to illustrate the use of after(), clone(), before() methods.
// JAVA program explaining Date class methods
// after(), clone(), before()
import
java.util.Date;
public
class
NewClass
{
public
static
void
main(String[] args)
{
// create 2 dates
Date date1 =
new
Date(
2016
,
11
,
18
);
Date date2 =
new
Date(
1997
,
10
,
27
);
// Use of after() to check date2 is after date1
boolean
a = date2.after(date1);
System.out.println(
"Is date2 is after date1 : "
+ a);
// Use of after() to check date2 is after date1
a = date1.after(date2);
System.out.println(
"Is date1 is after date2 : "
+ a);
System.out.println(
""
);
// Use of clone() method
Object date3 = date1.clone();
System.out.println(
"Cloned date3 :"
+ date3.toString());
System.out.println(
""
);
// Use of before() to check date2 is after date1
boolean
b = date2.before(date1);
System.out.println(
"Is date2 is before date1 : "
+ a);
}
}
Output :
Is date2 is after date1 : false Is date1 is after date2 : true Cloned date3 :Mon Dec 18 00:00:00 IST 3916 Is date2 is before date1 : true
- .compareTo() : java.util.Date.compareTo() method compares two dates and results in -1, 0 or 1 based on the comparison.
Syntax: public int compareTo(Date argDate) Parameters: argDate : another date to compare with Result: 0 : if the argumented date = given date. -1 : if the argumented date > given date. 1 : if the argumented date < given date.
- .equals() : java.util.Date.equals() method checks whether two dates are equal or not based on their millisecond difference.
Syntax: public boolean equals(Object argDate) Parameters: argDate : another date to compare with Result: true if both the date are equal; else false.
- .getTime() : java.util.Date.getTime() method results in count of milliseconds of the argumented date, referencing January 1, 1970, 00:00:00 GMT.
Syntax: public long getTime() Result: milliseconds of the argumented date, referencing January 1, 1970, 00:00:00 GMT.
Java Code to illustrate the use of compareTo(), getTime(), equals() methods.
// Java program explaining Date class methods
// compareTo(), getTime(), equals()
import
java.util.*;
public
class
NewClass
{
public
static
void
main(String[] args)
{
Date d1 =
new
Date(
97
,
10
,
27
);
Date d2 =
new
Date(
97
,
6
,
12
);
// Use of compareto() method
int
comparison = d1.compareTo(d2);
// d1 > d2
int
comparison2 = d2.compareTo(d1);
// d2 > d1
int
comparison3 = d1.compareTo(d1);
// d1 = d1
System.out.println(
"d1 > d2 : "
+ comparison);
System.out.println(
"d1 < d2 : "
+ comparison2);
System.out.println(
"d1 = d1 : "
+ comparison3);
System.out.println(
""
);
// Use of equal() method
boolean
r1 = d1.equals(d2);
System.out.println(
"Result of equal() r1 : "
+ r1);
boolean
r2 = d1.equals(d1);
System.out.println(
"Result of equal() r2 : "
+ r2);
System.out.println(
""
);
// Use of getTime() method
long
count1 = d1.getTime();
long
count2 = d1.getTime();
System.out.println(
"Milliseconds of d1 : "
+ count1);
System.out.println(
"Milliseconds of d2 : "
+ count2);
}
}
Output :
d1 > d2 : 1 d1 < d2 : -1 d1 = d1 : 0 Result of equal() r1 : false Result of equal() r2 : true Milliseconds of d1 : 880569000000 Milliseconds of d2 : 880569000000
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