java - 为什么 Collections.sort() 只适用于列表而不适用于集合？

Question

为什么 Collections.sort() 仅适用于 List 而不适用于 Set？有什么特别的原因吗？

Answer 1

大多数(但不是全部)Set 实现没有顺序的概念，因此 Collections.sort 不支持它们作为所有的。如果你想要一个有顺序概念的集合，你可以使用像 TreeSet 这样的东西。 :

A NavigableSet implementation based on a TreeMap. The elements are ordered using their natural ordering, or by a Comparator provided at set creation time, depending on which constructor is used.

或者一个LinkedHashSet :

Hash table and linked list implementation of the Set interface, with predictable iteration order. This implementation differs from HashSet in that it maintains a doubly-linked list running through all of its entries. This linked list defines the iteration ordering, which is the order in which elements were inserted into the set (insertion-order)