Calendar的中文翻译是日历，实际上，在历史上有着许多种计时的方法。所以为了计时的统一，必需指定一个日历的选择。那现在最为普及和通用的日历就是"Gregorian Calendar"。也就是我们在讲述年份时常用"公元**年"。Calendar 在 Java 中是一个抽象类(Abstract Class)，GregorianCalendar 是它的一个具体实现。Calendar.getInstance()中所获得的实例就是一个"GreogrianCalendar"对象。

Calendar获取时间的常见方法(The Chinese translation of Calendar is a calendar. In fact, there are many ways of timing in history. Therefore, in order to unify the timing, you must specify the choice of a calendar. Now the most popular and versatile calendar is "Gregorian Calendar"". That is, when we are talking about the year, it is often used in a.d.". Calendar is an abstract class (Abstract, Class) in Java, and GregorianCalendar is a concrete implementation of it. The instance obtained in Calendar.getInstance () is a "GreogrianCalendar" object.
Calendar common ways to get time)