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
",year,month,day,hour,minute,second);
        System.out.println(date);

计算两个时间差的天数

比如2012/9/1和2016/7/1

        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)));

 借助Calendar写一个显示日历的类

class CalendarFuck{
    int year,month;
    String[] getCalendar(){
        String []a=new String[43];
        Calendar Calender1=Calendar.getInstance();
        Calender1.set(year, month-1,1);
        int weekday=Calender1.get(Calender1.DAY_OF_WEEK)-1;
//        System.out.println(month);
        int day = 0;
        if(month==1||month==3||month==5||month==7||month==8||month==10||month==12){
            day=31;
        }else if(month==4||month==6||month==9|month==11)
            day=30;
        else if(month==2){
            if(year%4==0&&year%100!=0||year%400==0)
                day=29;
            else 
                day=28;
        }
        for(int i=0;i<weekday;i++)
            a[i]=" ";
        for(int i=weekday,n=1;i<weekday+day;i++){
            a[i]=String.valueOf(n);
            n++;
        }
        for(int i=weekday+day;i<a.length;i++){
            a[i]=" ";
        }
        return a;
    }
}