Use Java to do time subtraction

Utilize the Gettimeinmillis () method of the GregorianCalendar class.


Note that the value taken is the number of microseconds that have elapsed since 00:00:00 January 1, 1970. One second is 1000 microseconds.





The following is a routine written by yourself and the results of the operation:





import Java.util.GregorianCalendar;





class Testclender {





public static void Main (String args[]) {





GregorianCalendar CA = new GregorianCalendar ();


System.out.println ("CA:" + CA);


System.out.println ("ca.time:" + ca.gettimeinmillis ());





GregorianCalendar ca0 = new GregorianCalendar (2004-1900,11,31,23,59,59);


GregorianCalendar CA1 = new GregorianCalendar (2005-1900,00,01,00,00,02);


Long sa = Ca1.gettimeinmillis ()-Ca0.gettimeinmillis ();


System.out.println ("ca1-ca0:" + sa);





//2004.11.05 added


String old = "20041231235959";


int old_yyyy = Integer.parseint (old.substring (0,4));


int old_mm = Integer.parseint (old.substring (4,6));


int old_dd = Integer.parseint (old.substring (6,8));


int old_hh = Integer.parseint (old.substring (8,10));


int old_mi = Integer.parseint (old.substring (10,12));


int old_ss = Integer.parseint (old.substring (12,14));


String now = "20050101235959";


int now_yyyy = Integer.parseint (now.substring (0,4));


int now_mm = Integer.parseint (now.substring (4,6));


int now_dd = Integer.parseint (now.substring (6,8));


int now_hh = Integer.parseint (now.substring (8,10));


int now_mi = Integer.parseint (now.substring (10,12));


int now_ss = Integer.parseint (now.substring (12,14));


GregorianCalendar gcold = new GregorianCalendar (


OLD_YYYY-1900,OLD_MM-1,OLD_DD,OLD_HH,OLD_MI,OLD_SS);


GregorianCalendar gcnow = new GregorianCalendar (


NOW_YYYY-1900,NOW_MM-1,NOW_DD,NOW_HH,NOW_MI,NOW_SS);


sa = Gcnow.gettimeinmillis ()-Gcold.gettimeinmillis ();


System.out.println ("now-old:" + sa);





}





}