java - Java中的双向 map ？

Question

这个问题在这里已经有了答案:

Bidirectional Map (9 个回答)

关闭 8年前.

我在 Java 中有一个简单的整数到字符串的映射，但我需要能够轻松地从整数中检索字符串，以及从字符串中检索整数。我试过 Map，但它只能从整数中检索字符串，这是一种方式:

private static final Map<Integer, String> myMap = new HashMap<Integer, String>();
// This works one way:
String myString = myMap.get(myInteger);

// I would need something like:
Integer myInteger = myMap.getKey(myString);

有没有正确的方法来做到这两个方向？

另一个问题是我只有几个不变的值(1->"low", 2->"mid", 3->"high"，所以它不值得去寻求一个复杂的解决方案。

Answer 1

您可以为此使用 Google Collections API， 最近 重命名为 Guava ，特别是 BiMap

A bimap (or "bidirectional map") is a map that preserves theuniqueness of its values as well as that of its keys. This constraintenables bimaps to support an "inverse view", which is another bimapcontaining the same entries as this bimap but with reversed keys andvalues.