1. Calendar类型转化为Date类型和long类型

Calendar calendar=Calendar.getInstance();

Date date=calendar.getTime();

long time=calendar.getTimeInMillis();

2.Date类型转化为Calendar类型和long类型

Date date=new Date(System.currentTimeMillis()+100000000);

Calendar calendar=Calendar.getInstance();

calendar.setTime(date);

long time=date.getTime();

3. long类型转化为Date类型和Calendar类型

long time=System.currentTimeMillis()+100000000;

Date date=new Date(time);

Calendar calendar=Calendar.getInstance();

calendar.setTimeInMillis(time);