聊聊Spring WebFlux
先来梳理一下关系。
Reactive Streams
Reactive Streams是一个规范，定义了处理异步数据流的标准，包括了发布者(Publisher)、订阅者(Subscriber)、订阅(Subscription)、处理 器(Processor)等核心接口和规则。 它为异步编程提供了一个统一的基础，解决了背压(Back Pressure)等问题。
详细见：https://github.com/reactive-streams/reactive-streams-jvm/blob/v1.0.4/README.md
Java 9 Flow API
此外，Java 9引入的java.util.concurrent.Flow与Reactive Streams在语义上是1：1等价的。
JDK9 java.util.concurrent.Flow
The interfaces available in JDK >= 9 java.util.concurrent.Flow, are 1:1 semantically equivalent to their respective Reactive Streams counterparts. This means that there will be a migratory period, while libraries move to adopt the new types in the JDK, however this period is expected to be short - due to the full semantic equivalence of the libraries, as well as the Reactive Streams <-> Flow adapter library as well as a TCK compatible directly with the JDK Flow types.
Project Reactor
而Project Reactor则是这个规范的一种具体实现。它提供了Reactive Streams规范接口的不同实现，以及一组符合 规范的操作符，从而让开发者能够方便地进行响应式编程。
有关Project Reactor的书很少，分享一本免费的在线电子书。Unraveling Project Reactor
RxJava
RxJava 3是一个基于观察者模式的Java编程库，用于实现异步、基于事件的程序。作为Reactive Streams规范的实现之一，RxJava 3遵循了 Reactive Streams的接口和协议。