为什么使用EnumMap而不是HashMap [英] Why use EnumMap instead of HashMap

问题描述

我们已经有了HashMap，为什么还要使用EnumMap?

As we already have HashMap, why would we use EnumMap?

推荐答案

Javadoc 提出了一个很好的论据:

The Javadoc makes a pretty good argument:

枚举映射在内部表示为数组.这种表示非常紧凑和高效.

Enum maps are represented internally as arrays. This representation is extremely compact and efficient.

实施说明:所有基本操作均在固定时间内执行.它们可能(尽管不能保证)比其HashMap同行更快.

Implementation note: All basic operations execute in constant time. They are likely (though not guaranteed) to be faster than their HashMap counterparts.

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