Java Cookbook

Finding Today’s Date

Problem

You want to find today’s date.

Solution

Use a Date object’s toString( ) method.

Discussion

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^[21]), and print the resulting Date object, either using its toString( ) method or a DateFormat object. You might be tempted to construct a GregorianCalendar object, using the no-argument constructor, but if you do this, your program will not give the correct answer when non-western locales get Calendar subclasses of their own (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 (someday) 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.

// Date1,.javaj ...