有比 int Java List 更长的吗? [英] Is there a longer than int Java List?

问题描述

我似乎找不到最大长度是 long 的最大值的 Java List.

I can't seem to find a Java List that's max length is long's max value.

这样的List存在吗?

如果有，在哪里?

推荐答案

正如@afsantos 所说，ArrayList 类本质上仅限于 Integer.MAX_VALUE 条目，因为Java 数组的局限性.

As @afsantos says, the ArrayList class is inherently limited to Integer.MAX_VALUE entries because of the limitations of Java arrays.

LinkedList 没有这个限制，但它(尽管如此)很昂贵:

LinkedList doesn't have this limitation, but it is (nonetheless) expensive:

• 与基于数组的表示仅一个引用相比，每个条目都会产生 2 个引用加上对象头大小的内存开销.

• Each entry incurs an memory overhead of 2 references plus the size of an object header ... compared to just one reference for an array-based representation.

与基于数组的列表的O(1)相比，索引是一个O(N)操作.

Indexing is an O(N) operation compared with O(1) for an array-based list.

这里是 Java 库的链接，该库支持使用直接映射内存和/或元素编码的巨大内存中集合:

Here is a link to Java library that supports huge in-memory collections using direct mapped memory and/or encoding of the elements:

• http://code.google.com/p/vanilla-java/wiki/HugeCollections

可能还有其他选择.

人们还可以设想使用数组数组而不是单个数组的常规数组列表的大"变体.但是如果你允许插入到列表的中间，实现 O(1) 查找变得困难/昂贵.(这可能就是我找不到 Google 示例的原因...)

One could also envisage a "big" variant of regular array lists that used an array of arrays rather than a single array. But if you allow insertion into the middle of the list, it becomes difficult / expensive to achieve O(1) lookup. (That might be why I couldn't find an example with Google ...)

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