1.Calendar 是一个抽象类,并且构造器是private
2.我们只能通过getInstance()来获取实例
3.里面包含了大量的字段和方法提供给程序员
4. Calendar 没有提供对应的格式化的类,因此需要程序员自己组合来输出(灵活)
5.如果我们想要使用24小时制 Calendar.Hour ==改成==> Calendar.HOUR_OF_DAY
Calendar calendar = Calendar.getInstance();System.out.println("获取字段信息"+calendar);System.out.println("year:"+calendar.get(Calendar.YEAR));//Month获取日历的时候,是按照0开始编号的,因此需要自行加1System.out.println("Month:"+(calendar.get(Calendar.MONTH)+1));System.out.println("Date:"+calendar.get(Calendar.DATE));
// System.out.println("Date:"+calendar.get(Calendar.DAY_OF_MONTH));System.out.println("12h-Hour:"+ calendar.get(Calendar.HOUR));System.out.println("24h-Hour"+calendar.get(Calendar.HOUR_OF_DAY));System.out.println("Minute:"+calendar.get(Calendar.MINUTE));System.out.println("Second:"+calendar.get(Calendar.SECOND));// Calendar 没有提供对应的格式化的类,因此需要程序员自己组合来输出(灵活)System.out.println("北京时间:"+calendar.get(Calendar.YEAR)+"-"+(calendar.get(Calendar.MONTH)+1)+"-"+calendar.get(Calendar.DATE)+"\t"+calendar.get(Calendar.HOUR)+":"+calendar.get(Calendar.MINUTE)+":"+ calendar.get(Calendar.SECOND));
LocalDateTime、LocalDate、LocalTime:
System.out.println("=======第三代日期类表示法=======");LocalDateTime ldt = LocalDateTime.now();System.out.println(ldt);System.out.println("年"+ldt.getYear());System.out.println("月:"+ldt.getMonthValue());System.out.println("日:"+ldt.getDayOfMonth());System.out.println("时"+ldt.getHour());System.out.println("分"+ldt.getMinute());System.out.println("秒"+ldt.getSecond());System.out.println("========LocalDate=======");//LocalDate只能获取年月日LocalDate lod = LocalDate.now();System.out.print("年:"+lod.getYear());System.out.print(" 月:"+lod.getMonthValue());System.out.print(" 日:"+lod.getDayOfMonth());System.out.println("========LocalTime=======");//LocalTime只能获取时分秒LocalTime lot = LocalTime.now();System.out.print("时:"+lot.getHour());System.out.print(" 分:"+lot.getMinute());System.out.print(" 秒:"+lot.getSecond());