克隆 GregorianCalendar 的最快方法是什么?

2022-01-11 00:00:00 复制 clone calendar java

我正在尝试制作一个对象的深层副本,包括一个 GregorianCalendar 实例.我总是对使用 clone() 持谨慎态度,而且这里似乎没有被覆盖,所以我只是逐个字段地进行复制.理想情况下,会有一个复制构造函数,我可以像这样使用它:

I'm trying to make a deep copy of an object, including a GregorianCalendar instance. I'm always wary of using clone() and it doesn't seem to have been overridden here, so I'm just doing the copy field by field. Ideally, there'd be a copy constructor, which I could use like so:

GregorianCalendar newCalendar = new GregorianCalendar(oldCalendar);

不幸的是,我在 API 中找不到任何此类功能,并且一直在试图找出我需要哪些字段才能获得准确的副本.那么,要复制其中一个日历,你会怎么做呢?我在这里错过了一些简单的快捷方式吗?

Unfortunately I can't find any such functionality in the API and am stuck trying to figure out which fields I need to get an exact copy. So, to make a copy of one of these calendars, how would you do it? Am I missing some simple shortcut here?

推荐答案

java.util.Calendar 已经覆盖了正在工作的 clone(),所以使用它.此外,Calendar 没有很深的数据层次——它的数据主要是 ints.

java.util.Calendar has overridden clone() which is working, so use it. Furthermore, Calendar doesn't have a deep data hierarchy — its data are mainly ints.

要扩展答案,您可以调用 SerializationUtils.clone(...) (来自 Apache commons-lang)在任何进行深拷贝的对象上,如果整个数据层次结构实现 Serializable.

To extend the answer, you can call SerializationUtils.clone(…) (from Apache commons-lang) on any object which makes a deep copy, if the whole data hierarchy implements Serializable.

相关文章