MultiValueMap

最新推荐文章于 2024-02-10 12:01:28 发布

chenpan1988

最新推荐文章于 2024-02-10 12:01:28 发布

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本文介绍了一种名为MultiValueMap的数据结构，它是Apache Commons Collections库的一部分。这种数据结构允许一个键对应多个值，并提供了灵活的选择来控制这些值所存储的集合类型，默认使用ArrayList。值得注意的是，MultiValueMap本身不是线程安全的。

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An easy to use class.

A MultiValueMap decorates another map, allowing it to have more than one value for a key.

A MultiMap is a Map with slightly different semantics. Putting a value into the map will add the value to a Collection at that key. Getting a value will return a Collection, holding all the values put to that key.

This implementation is a decorator, allowing any Map implementation to be used as the base.

In addition, this implementation allows the type of collection used for the values to be controlled. By default, an ArrayList is used, however a Class to instantiate may be specified, or a factory that returns a Collection instance.

Note that MultiValueMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. This class may throw exceptions when accessed by concurrent threads without synchronization.

Reference:

http://commons.apache.org/proper/commons-collections/javadocs/api-3.2.1/org/apache/commons/collections/map/MultiValueMap.html