使用java存储键值对
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Storing Key, Value Pair using java
提问by Awinash
I would like to know the best data structure used in java suitable for the following senario.
我想知道适用于以下 senario 的 java 中使用的最佳数据结构。
- There is a key and a value.
- And the key is not duplicated,
- Each Value should store collection of objects where the values in each object will change frequently.
- 有一个键和一个值。
- 并且密钥不重复，
- 每个值应存储对象的集合，其中每个对象中的值将频繁更改。
Thanks.
谢谢。
采纳答案by Juned Ahsan
HashMapshould serve your need.
HashMap应该可以满足您的需求。
HashMap allows you to store key value pairs as a collection. HashMap does not allow duplicate keys. You can use different collection to be stored as a value in your HashMap. For example to create a map with keys as a String and value as a list, the define it like this:
HashMap 允许您将键值对存储为集合。HashMap 不允许重复键。您可以使用不同的集合作为值存储在 HashMap 中。例如，要创建一个键作为字符串和值作为列表的映射，像这样定义它：
Map<String, List<String>> = new HashMap<String, List<String>>();
Also there are implementations for such collection called MultiMap i.e map where a key is associated with collection of values. Two popular implemantations of MultiMap are:
也有这种集合的实现称为 MultiMap，即映射，其中一个键与值的集合相关联。MultiMap 的两种流行实现是：
- Apacha MultiMap
- Guava MultiMap
- 阿帕查多图
- 番石榴多图
回答by Lan
A type of map. You aren't saying much besides "I need a key-value thingy". If you need to iterate the map by insertion order, there is a LinkedHashMap. If you need to iterate the map by ascending or descending key values, there are sorted maps. If the map will be shared by multiple threads a concurrent mapwill be useful. If there will be billions of items in the list and you don't mind hemorraghing data (say this is a caching algorithm), a WeakHashMapis for you.
一种地图。除了“我需要一个键值的东西”之外，你并没有说太多。如果您需要按插入顺序迭代映射，则有一个 LinkedHashMap。如果您需要通过升序或降序键值来迭代地图，则可以使用已排序的地图。如果映射将由多个线程共享，则并发映射将很有用。如果列表中有数十亿个项目并且您不介意大量数据（比如这是一种缓存算法），那么WeakHashMap适合您。
If by "key is not duplicated" you mean it is a violation if a key is inserted if it already exists, you have a few options.
如果“密钥不重复”意味着如果密钥已经存在，则插入它是一种违规行为，您有几个选择。
