Date及DateFormat用法

Date 与DateFormat之间的转化
String <————>Date

Date与Calendar 之间的转化
Long<————>Date

日历小程序

Scanner input=new Scanner(System.in);
        String str=input.nextLine();
        String time=str;
        DateFormat date=new SimpleDateFormat("yyyy-MM-dd");
        Date date1=date.parse(time);
        Calendar cal=new GregorianCalendar();
        cal.setTime(date1);
        int day_month=cal.get(Calendar.DAY_OF_MONTH);
        int total=cal.getActualMaximum(Calendar.DATE);
        cal.set(Calendar.DATE, 1);
        int weekday=cal.get(Calendar.DAY_OF_WEEK);
        System.out.println(total);
        System.out.println(weekday);
        System.out.println("日\t一\t二\t三\t四\t五\t六\n");
        for(int i=1;i<weekday;i++){
            System.out.print("\t");
        }

        for(int i=1;i<=total;i++){
        if(i==day_month){
            System.out.print("*");
        }
        System.out.print(i+"\t");
        if(7==cal.get(Calendar.DAY_OF_WEEK)){
            System.out.println();
        }
        cal.add(Calendar.DATE, 1);
        }