怎么做网站免费的google关键词指数

前言

stream是怎么做到一次迭代中将所有流操作进行叠加？stream怎么做到只有在终止操作时进行元素遍历？那中间操作是做了些什么？

Stream 与集合的区别

• 集合是内存中的数据结构抽象，描述了数据在内存中是如何存储的。
• 流描述了对数据处理的过程，是一系列运算操作的叠加。

流可以是无限流，而集合不能是无限集合。

Stream 构成

Stream 原理解析

SizedRefSortingSink

ReducingSink

一次遍历，运行所有操作

参考

1. Difference Between Collections And Streams In Java

1. Collections are used to store and group the data in a particular data structure like List, Set or Map. But, streams are used to perform complex data processing operations like filtering, matching, mapping etc on stored data such as arrays, collections or I/O resources. That means, collections are mainly about data and streams are mainly about operations on data.
2. Collections are eagerly constructed i.e all the elements are computed at the beginning itself. But, streams are lazily constructed i.e intermediate operations are not evaluated until terminal operation is invoked.