獲取指點日期的月度等數值 時間set add的區別

獲取指點日期的月份等數值 時間set add的區別

 

private int getTheMonthsValue(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		return calendar.get(Calendar.MONTH) + 1;
	}

private int getTheMonthsValue2(Date date) {
		GregorianCalendar g = new GregorianCalendar();
		g.setTime(date);
		int flag = (int) g.get(Calendar.MONTH) + 1;
		return flag;
	}

真悲劇 居然沒留意到 Calendar這個類有add() 和 set()區別;

private Date getTime(Date date) {
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		calendar.set(Calendar.DATE, 1);
		return calendar.getTime();
	}

	private Date getTime2(Date date) {
		Calendar lastDate = Calendar.getInstance();
		lastDate.setTime(date);
		lastDate.add(Calendar.DAY_OF_MONTH, 1);
		return lastDate.getTime();
	}

System.out.println(dateFormat.format(test.getTime(date)));
		System.out.println(dateFormat.format(test.getTime2(date)));

結果:

2011-07-01
2011-07-16