linkedhashset
时间: 2023-07-15 17:11:34 浏览: 56
LinkedHashSet是Java集合框架中的一种类,它实现了Set接口,同时使用链表维护元素的插入顺序。和HashSet一样,LinkedHashSet也是基于哈希表的,但是它在哈希表的基础上通过链表维护了元素的插入顺序,因此可以保证元素的顺序性。与HashSet相比,LinkedHashSet的插入和删除操作的时间复杂度都是O(1),但是由于需要维护元素的顺序,所以访问操作的时间复杂度比HashSet略慢一些。在实际应用中,如果需要维护元素的插入顺序,可以使用LinkedHashSet;否则可以使用HashSet,因为HashSet的空间效率更高。
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LinkedHashSet
LinkedHashSet is a subclass of HashSet in Java that maintains the insertion order of the elements. It extends the HashSet class and implements the Set interface. It is similar to HashSet in terms of storing unique elements but maintains the order in which the elements were inserted.
LinkedHashSet uses a combination of a hash table and a linked list to maintain the elements in the order in which they were inserted. It provides constant time performance for the basic operations such as add, remove, contains, and size.
One of the main advantages of LinkedHashSet over HashSet is that it can be used in scenarios where the order of the elements is important. For example, in a web application, a LinkedHashSet can be used to store the order of the pages that a user has visited.
LinkedHashSet is not synchronized, so it is not thread-safe. However, it can be synchronized using the Collections.synchronizedSet() method to make it thread-safe.
Overall, LinkedHashSet is a useful class in Java that provides the benefits of HashSet along with maintaining the order of the elements.
- LinkedHashSet
LinkedHashSet是Java中的一种特殊类型的集合,它是HashSet的子类,同时也实现了Set接口。与HashSet不同的是,LinkedHashSet能够保持元素的插入顺序。
LinkedHashSet内部使用了哈希表和双向链表的结合,这样既能够快速访问元素(通过哈希表),又能够维护元素的插入顺序(通过双向链表)。
LinkedHashSet具有以下特点:
1. 无序性:与HashSet类似,LinkedHashSet中的元素是无序的,不保证按照插入顺序或其他顺序进行迭代。
2. 唯一性:LinkedHashSet不允许重复元素,即相同的元素只会保存一次。
3. 插入顺序:LinkedHashSet会按照元素的插入顺序进行迭代,保持元素的顺序不变。
4. 高效性:LinkedHashSet具有较快的访问和操作性能,时间复杂度为O(1)。
由于LinkedHashSet既保持了HashSet的查找性能优势,又保持了元素的插入顺序,因此在需要保持元素插入顺序的场景下,可以选择使用LinkedHashSet。