需要对值具有多个键的 Java 映射/表.值通常会改变
it1352
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问题说明
我需要的是一个允许多个键访问单个对象的集合.
What I need is a collection which allows multiple keys to access a single object.
我需要对此对象进行频繁的更改.
I need to apply frequent alterations to this object.
它还必须对 500k 个条目有效.
It also must be efficient for 500k entries.
正确答案
#1
java.util.Map<K,V> 的任何实现都可以做到这一点 - 没有限制 在单独的键下可以添加特定值多少次:
Any implementation of java.util.Map<K,V> will do this - there is no restriction on how many times a particular value can be added under separate keys:
Map<String,Integer> m = new HashMap<String, Integer>();
m.put("Hello", 5);
m.put("World", 5);
System.out.println(m); // { Hello->5, World->5 }
如果您想要一个单一键与多个值相关联的地图，这称为 多地图，您可以从 谷歌 java 集合 API 或来自 Apache的commons-collections
If you want a map where a single key is associated with multiple values, this is called a multi-map and you can get one from the 谷歌 java collections API or from Apache's commons-collections
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