Date与Calendar

        Date date=new Date();//现在时间
        Date date1=new Date(1000);//格林威治时间1997/01/01开始算，后面的是毫秒
        Calendar calendar=Calendar.getInstance();//获得一个月历
        calendar.set(2016, 0,01);
        calendar.setTime(new Date());//setTime的时候才可以用new Date（）
        int year=calendar.get(Calendar.YEAR),
        month=calendar.get(Calendar.MONTH)+1,
        day=calendar.get(Calendar.DAY_OF_MONTH),
        hour=calendar.get(Calendar.HOUR_OF_DAY),
        minute=calendar.get(Calendar.MINUTE),
        second=calendar.get(Calendar.SECOND);
        System.out.printf("%d,%d,%d,%d,%d,%d\n",year,month,day,hour,minute,second);
        System.out.println(date);

        Calendar calendar1=Calendar.getInstance();
        Calendar calendar2=Calendar.getInstance();
        calendar1.set(2012, 9,1);
        calendar2.set(2016, 7,1);
        long time1=calendar1.getTimeInMillis();//貌似是获得时间绝对值的函数
        long time2=calendar2.getTimeInMillis();
        System.out.println(Math.abs((time1-time2)/(1000*60*60*24)));