可以存储在HashMap中的键（对象）的数量的理论极限？ [英] Theoretical limit for number of keys (objects) that can be stored in a HashMap?

问题描述

对于可以存储在HashMap中的关键条目的数量是否存在理论上的限制，还是纯粹依赖于可用的堆内存？

另外，哪个数据结构最适合存储大量对象（比如说几十万个对象）？

观看该类的文档，我会说理论限制是 Integer.MAX_VALUE 31 -1 = 2147483647）元素。

这是因为要正确实现这个类， size（） code> 方法必须返回 int ，表示键/值对的数目。

星期五om HashMap.size（）
$ b

返回： 此映射中键值映射的数量

注意：此问题与< a href =https://stackoverflow.com/a/3768038/276052>列表最多可容纳多少个数据。

---

哪个数据结构最适合存储大量对象（比如说几十万个对象）？

我想说这取决于你需要存储什么以及你需要什么类型的访问。所有内置收藏品都可能为大批量优化。

Is there a theoretical limit for the number of key entries that can be stored in a HashMap or does it purely depend on the heap memory available?

Also, which data structure is the best to store a very large number of objects (say several hundred thousand objects)?

解决方案

Is there a theoretical limit for the number of key entries that can be stored in a HashMap or does it purely depend on the heapmemory available ?

Looking at the documentation of that class, I would say that the theoretical limit is Integer.MAX_VALUE (2³¹-1 = 2147483647) elements.

This is because to properly implement this class, the size() method is obliged to return an int representing the number of key/value pairs.

From the documentation of HashMap.size()

Returns: the number of key-value mappings in this map

Note: This question is very similar to How many data a list can hold at the maximum.

---

which data structure is the best to store a very large number of objects(say several hundred thousand objects)?

I would say it depends on what you need to store and what type of access you require. All built in collections are probably well optimized for large quantities.

这篇关于可以存储在HashMap中的键（对象）的数量的理论极限？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！