Convert the number of milliseconds to the date to get the number of days

Dateformat formatter = new simpledateformat ("yyyy-mm-dd hh: mm: SS ");
Long Now = system. currenttimemillis ();
Calendar calendar = calendar. getinstance ();
Calendar. settimeinmillis (now );
System. Out. println (now + "=" + formatter. Format (calendar. gettime ()));
// Convert the date to two dates in milliseconds to reduce the number of days
Simpledateformat SDF = new simpledateformat ("yyyy-mm-dd hh: mm: SS ");
String start = "12:30:45 ";
String end = "6:30:00 ";
// Obtain the number of milliseconds
Long timestart = SDF. parse (start). gettime ();
Long timeend = SDF. parse (end). gettime ();
// The number of days to be subtracted from two dates
Long daycount = (timeend-timestart)/(24*3600*1000 );
System. Out. println (daycount );

Convert the number of milliseconds to the date to get the number of days