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在Java编程语言中，HashMap是一个基于哈希表的Map接口实现，它提供了一种使用键来访问关联值的数据结构。由于其高效性和易用性，HashMap成为了Java程序中最常用的集合之一。本文将深入探讨HashMap的工作原理、性能特点以及优化策略，并通过示例代码加以说明。一、哈希表原理哈希表（H...

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HashMap和哈希表数据结构**HashMap集合key部分允许null吗?允许但是要注意:HashMap集合的key null值只能有一个。有可能面试的时候遇到这样的问题。****HashMap集合:1、HashMap集合底层是哈希表/散列表的数据结构。2、哈希表是一个怎样的数据结构呢?哈希表是...

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