獲得每月第一天凌晨時間
Calendar cal = Calendar.getInstance();
Calendar calfirstday = new GregorianCalendar(cal.get(Calendar.YEAR),cal.get(Calendar.MONTH),1);獲得每月第一天凌晨時間
Calendar cal = Calendar.getInstance();
Calendar calfirstday = new GregorianCalendar(cal.get(Calendar.YEAR),cal.get(Calendar.MONTH),1);