Java-Calendar用法

//獲取時間對象
		String string = (new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date()));
		System.out.println(string);
		
		Calendar calendar = Calendar.getInstance();
		
		//獲取年
		System.out.println("年:"+calendar.get(Calendar.YEAR));
		
		//月是從0開始 這裏要加1
		System.out.println("月:"+(calendar.get(Calendar.MONTH)+1));
	
		//表示本月中的某一天
		System.out.println("日:"+(calendar.get(Calendar.DAY_OF_MONTH)));
		
		//顯示這一年的某一天
		System.out.println("日:"+(calendar.get(Calendar.DAY_OF_YEAR)));
		
		//顯示星期第幾天
		System.out.println("日:"+(calendar.get(Calendar.DAY_OF_WEEK)));
		
		//小時相加
		calendar.add(Calendar.HOUR,3);

		//獲取小時
		System.out.println("小時:"+(calendar.get(Calendar.HOUR)));
		//加十分鐘
		calendar.add(Calendar.MINUTE, 10);
		//獲取分鐘
		System.out.println(calendar.get(Calendar.MINUTE));
		//減十分鐘
		calendar.add(Calendar.MINUTE, -10);
		
		//重置時間
		calendar.setTime(new Date());  
		string = (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SS")).format(calendar.getTime());  
		System.out.println(string);  
		
		
		//時間比較
		
		Calendar calendarOld = Calendar.getInstance();
		calendarOld.setTime(new Date());
		Calendar calendarNew = Calendar.getInstance();
		calendarNew.setTime(new Date());
		
		//加一年
		calendarNew.add(Calendar.YEAR, 1);
		
		//calendarNew > calendarOld 返回大1 否則-1
		if(calendarNew.compareTo(calendarOld) != -1)
		{
			System.out.println("當前時間大:"+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SS").format(calendarNew.getTime()));
		}
		
		//判斷的新時間是不是在老時間之後{表示的時間是否在指定 Object 表示的時間之後}
		if(calendarNew.after(calendarOld))
		{
			System.out.println("yes!");
		}
		
		//判斷時間是不是在老的時間之前
		if(calendarNew.before(calendarOld))
		{
			System.out.println("yes!");
		}