Java date addition and subtraction.

1. UseJava. Util. calender to implement

Calendar calendar = calendar. getinstance ();
Calendar. settime (new date ());
System. Out. println (calendar. Get (calendar. day_of_month); // today's date
Calendar. Set (calendar. day_of_month, calendar. Get (calendar. day_of_month) + 1); // Add 1 to the date.
System. Out. println (calendar. Get (calendar. Date); // Add the top date after 1
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2. UseJava. Text. simpledateformat andJava. Util. Date

Date d = new date ();
Simpledateformat df = new simpledateformat ("yyyy-mm-dd ");
System. Out. println ("today's date:" + DF. Format (d ));
System. out. println ("date two days ago:" + DF. format (new date (D. gettime ()-2*24*60*60*1000 )));
System. Out. println ("three days later:" + DF. Format (new date (D. gettime () + 3*24*60*60*1000 )));

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Gregoriancalendar GC = new gregoriancalendar ();
GC. settime (new date );
GC. Add (field, value );
Value is followed by a regular expression, and if it is negative, it goes forward.
Field Values: 1 plus 1 year, 2 plus half year, 3 plus 1 quarter, 4 plus 1 week
5 plus one day ....

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/*
*JavaAddition and subtraction of dates
* GC. Add (1,-1) indicates the year minus one.
* GC. Add (2,-1) indicates the month minus one.
* GC. Add (3.-1) indicates that one week is subtracted.
* GC. Add (5,-1) indicates a day minus one.
* Likewise, it should be accurate to milliseconds. If you haven't tried again, you can try it.
* The add (INT field, int amount) method of the gregoriancalendar class indicates addition and subtraction of year, month, and day.
* The field parameter indicates year, month, and day.
* The amount parameter indicates the quantity to be added or subtracted.
*
* Usedate.JavaThe test is as follows:
*/
Package temp. util;

Import
Java. Util. calendar;
ImportJava. Util. date;
ImportJava. Util. gregoriancalendar;
ImportJava. Text. simpledateformat;
Public class usedate {

Date d = new date ();
Gregoriancalendar GC = new gregoriancalendar ();
Simpledateformat Sf = new simpledateformat ("yyyy-mm-dd ");

Public String getyears ()
{
GC. settime (d );
GC. Add (1, + 1 );
GC. Set (GC. Get (calendar. Year), GC. Get (calendar. month), GC. Get (calendar. Date ));

Return SF. Format (GC. gettime ());
}

Public String gethalfyear ()
{
GC. settime (d );
GC. Add (2, + 6 );
GC. Set (GC. Get (calendar. Year), GC. Get (calendar. month), GC. Get (calendar. Date ));

Return SF. Format (GC. gettime ());
}
Public String getquarters ()
{
GC. settime (d );
GC. Add (2, + 3 );
GC. Set (GC. Get (calendar. Year), GC. Get (calendar. month), GC. Get (calendar. Date ));

Return SF. Format (GC. gettime ());
}

Public String getlocaldate ()
{
Return SF. Format (d );
}

Public static void main (string [] ARGs)
{
Usedate UD = new usedate ();
System. Out. println (ud. getlocaldate ());
System. Out. println (ud. getyears ());
System. Out. println (ud. gethalfyear ());
System. Out. println (ud. getquarters ());
}

}

 

 

4,

Gregoriancalendar GC = new gregoriancalendar ();

Try {
GC. settime (New simpledateformat ("yyyymm"). parse ("200901 "));
GC. Add (2,-integer. parseint ("7 "));
} Catch (parseexception e ){
// Todo automatically generates automatically generated writable catch writable
E. printstacktrace ();
}
System. Out. println (New simpledateformat ("yyyymm"). Format (GC. gettime ()));

Result: 200806