Java Finding Today’s Date - Web Development and Design | Tutorial for Java, PHP, HTML, Javascript Java Finding Today’s Date - Web Development and Design | Tutorial for Java, PHP, HTML, Javascript

Breaking

Post Top Ad

Post Top Ad

Thursday, January 3, 2019

Java Finding Today’s Date

Java Finding Today’s Date

Problem

You want to find today’s date.

Solution

Use a Date object’s toString( ) method.

Explained

The quick and simple way to get today’s date and time is to construct a Date object
with no arguments in the constructor call, and call its toString( ) method:

// Date0.java
System.out.println(new java.util.Date( ));

However, for reasons just outlined, we want to use a Calendar object. Just use Calendar.getInstance( ).getTime( ) , which returns a Date object (even though the name makes it seem like it should return a Time value * ) and prints the resulting Date object, using its toString( ) method or preferably a DateFormat object. You might be tempted to construct a GregorianCalendar object, using the no-argument construc- tor, but if you do this, your program will not give the correct answer when non- Western locales get Calendar subclasses of their own (which might occur in some future release of Java). The static factory method Calendar.getInstance( ) returns a localized Calendar subclass for the locale you are in. In North America and Europe it will likely return a GregorianCalendar , but in other parts of the world it might (some- day) return a different kind of Calendar . Do not try to use a GregorianCalendar ’s toString( ) method; the results are truly impressive, but not very interesting. Sun’s implementation prints all its internal state information; Kaffe’s inherits Object ’s toString( ) , which just prints the class name and the hashcode. Neither is useful for our purposes.

C> java Date1
java.util.
GregorianCalendar[time=932363506950,areFieldsSet=true,areAllFieldsSet=true,lenient=tr
ue,zone=java.util.SimpleTimeZone[id=America/Los_Angeles,offset=-
28800000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=3,startMonth=3,sta
rtDay=1,startDayOfWeek=1,startTime=7200000,endMode=2,endMonth=9,endDay=-
1,endDayOfWeek=1,endTime=7200000],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEA
R=1999,MONTH=6,WEEK_OF_YEAR=30,WEEK_OF_MONTH=4,DAY_OF_MONTH=18,DAY_OF_YEAR=199,DAY_
OF_WEEK=1,DAY_OF_WEEK_IN_MONTH=3,AM_PM=1,HOUR=10,HOUR_OF_
DAY=22,MINUTE=51,SECOND=46,MILLISECOND=950,ZONE_OFFSET=-28800000,DST_OFFSET=3600000]

Calendar ’s getTime( ) returns a Date object, which can be passed to println( ) to print today’s date (and time) in the traditional (but non-localized) format:

/ Date2.java
System.out.println(Calendar.getInstance( ).getTime( ));

No comments:

Post a Comment

Post Top Ad