翻译自：https://tech.io/playgrounds/929/reactive-programming-with-reactor-3/Intro
Introduction to Reactive Programming
Reactor 3 is a library built around the Reactive Streams
specification, bringing the paradigm of Reactive Programming
on the JVM.
Reactor 3是一个围绕反应流规范构建的库，在JVM上引入了反应式编程的范例。
In this course, you'll familiarize with the Reactor API.
So let's make a quick introduction to the more general concepts
in Reactive Streams and Reactive Programming.
在本课程中，您将熟悉Reactor API。让我们快速介绍一下反应流和反应编程中更一般的概念。
Why
Reactive Programming is a new paradigm in which you use declarative code
(in a manner that is similar to functional programming) in order to build
asynchronous processing pipelines. It is an event-based model where data
is pushed to the consumer, as it becomes available: we deal with asynchronous
sequences of events.
反应式编程是一种新的范式，在这种范式中，您使用声明性代码（以类似于函数式编程的方式）来构建异步处理管道。
它是一种基于事件的模型，当数据可用时，数据被推送到消费者手中：我们以异步事件序列来处理。
This is important in order to be more efficient with resources and increase
an application's capacity to serve large number of clients, without the
headache of writing low-level concurrent or and/or parallelized code.
为了更有效地利用资源，提高应用程序为大量客户机服务的能力，而不必编写低级并发或/或并行代码，这一点很重要。
By being built around the core pillars of being fully asynchronous and non-blocking,
Reactive Programming is an alternative to the more limited ways of doing asynchronous
code in the JDK: namely Callback based APIs and Future.
通过围绕完全异步和非阻塞的核心支柱构建，反应式编程是JDK中执行异步代码更有限方法的替代方法：
即基于Callback的API和Future。
It also facilitates composition, which in turn makes asynchronous code more
readable and maintainable.
它还促进了组合，从而使异步代码更具可读性和可维护性。
Reactive Streams
The Reactive Streams specification is an industry-driven effort to standardize
Reactive Programming libraries on the JVM, and more importantly specify how they
must behave so that they are interoperable. Implementors include Reactor 3 but also
RxJava from version 2 and above, Akka Streams, Vert.x and Ratpack.
反应流规范是一项行业驱动的工作，旨在标准化JVM上的反应式编程库，更重要的是指定它们的行为方式，
以使它们具有互操作性。实现者包括Reactor 3，也包括RxJava版本2及更高版本，Akka Streams，Vert.x和Ratpack。
It contains 4 very simple interfaces as well as a TCK, which shouldn't be overlooked
since it is the rules of the specification that bring the most value to it.
它包含4个非常简单的接口以及一个TCK，这不应该被忽视，因为规范的规则为它带来了最大的价值。
From a user perspective however, it is fairly low-level. Reactor 3 aims at offering an
higher level API that can be leverage in a large breadth of situations, building it on
top of Reactive Streams Publisher.
然而，从用户的角度来看，它是相当低级的。Reactor 3旨在提供一种更高级别的API，该API可以在广泛的情况下使用，
将其构建在反应流Publisher的基础上。
Interactions
In reactive stream sequences, the source Publisher produces data. But by default,
it does nothing until a Subscriber has registered (subscribed), at which point
it will push data to it.
在反应流序列中，源Publisher（发布者）生成数据。但默认情况下，在Subscriber（订阅者）注册（订阅）之前，
它什么也不做，订阅发生时它（Publisher）会将数据推送到它（Subscriber）。
Reactor adds the concept of operators, which are chained together to describe
what processing to apply at each stage to the data. Applying an operator returns a new
intermediate Publisher (in fact it can be thought of as both a Subscriber to the operator
upstream and a Publisher for downstream). The final form of the data ends up in the final
Subscriber that defines what to do from a user perspective.
Reactor增加了运算符（operators）的概念，将运算符链接在一起，以描述在每个阶段对数据应用什么处理。
应用运算符将返回一个新的中间发布者（实际上，它可以被视为运算符上游的订阅者和下游的发布者）。数据的最终形式在
最终订阅者中结束，该订阅者从用户角度定义了要做的事情。