如何订阅多个订阅者到 Observable 或 Flowable? [英] How to subscribe several subscribers to Observable or Flowable?

问题描述

在 Hello World 示例中，有一个订阅者

In Hello World example there is one subscriber

   public static void main(String[] args) {
      Flowable.just("Hello world").subscribe(System.out::println);
   }

如何制作两个或更多?

推荐答案

您可以为多个订阅者订阅任何 observable/flowable.只需根据需要多次重复 subscribe 调用即可.

You can subscribe multiple subsctibers to any observable/flowable. Just repeat subscribe call as many times as you need.

Flowable<String> source = Flowable.just("Hello world");
source.subscribe(System.out::println);
source.subscribe(System.out::println);
...

hot 和 cold observables 在处理如此多订阅的方式上有所不同.

There is difference in hot and cold observables in the way they handle such multiple subscriptions.

冷 observables/flowables 为每个新订阅者从源重新请求项目.例如，Flowable.fromCallable(c) 将在每次订阅时调用 c.

Cold observables/flowables re-request items from source for every new subscriber. For example, Flowable.fromCallable(c) will invoke c every time it is subscribed to.

Hot observables/flowables 与所有订阅者共享相同的源订阅，即它们不会为每个新订阅者从源请求新项目.新项目会传播给所有当前订阅的订阅者.

Hot observables/flowables share same source subscription with all subscribers, i.e. they do not request new items from source for every new subscriber. New items get propagated to all currently subscribed subscribers.

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