Rxjava概念初识与学习路径推荐

你的名字 2022-01-12 02:07 141阅读 0赞

RxJava是使用Java实现的响应式编程库，RxJava即 Reactive Extensions Java。目前有两个版本RxJava1和RxJava2,推荐使用RxJava2,RxJava1已经停止支持了

> ReactiveX即Reactive Extensions，它通过可观测的序列，实现了组合异步和事件驱动.它是一种编程方式。ReactiveX主要的实现方式是扩展 [观察者模式 ][Link 1]来达到自己的目的。[ReactiveX更多介绍戳官网][ReactiveX]

## RxJava学习路径与概念初始 ##

1.  了解什么是Observer什么是Observable? [英文原文][Link 2] 或者 [掘金翻译][Link 3]
    
    > Observer是观察者，Observable表明是可以被观察的。行人过红绿灯，行人是Observer,红绿灯的变化是可以Observable的
2.  初识命令式编程和响应式编程 [英文原文][Link 4] 或者 [掘金翻译][Link 5]
    
    > 实际项目中希望数据一发生变化就通知需要知道这个变化的对象，这可以通过观察者模式实现，数据变化观察者立马就可以对变化做出"响应"
3.  初识函数式编程 [英文原文][Link 6] 或者 [掘金翻译][Link 7]
4.  从java8中的stream到RxJava的转变 [英文原文][Link 8] 或者 [掘金翻译][Link 9]
5.  RxJava的一些API介绍 [英文原文][Link 10]
    
    > 创建Observable的基本方式，可以先了解最简单的just操作，[just的源码分析戳这里][just]
6.  了解什么是Hot Observable，什么是 Cold Observable，以及如何将Cold转换成Hot [英文原文][Link 11]
    
    >  *  cold:每次订阅和其它任何订阅它的取到的数据都是一样的
    >  *  hot:只能获取从订阅那一刻开始的数据，后续订阅的不能获取之前已经产生的数据
7.  Observer的方法介绍 [英文原文][Link 12]
    
    > onNext : 每次想通知 Observer 数据变化的时候，Observer的onNext方法就会被调用
8.  即是Observable又是Observer的对象 [英文原文][Link 13]
    
    > 相当于自己产生数据自己再消费
    > 
    >  *  PublishSubject获取订阅时候的数据
    >  *  BehaviourSubject可以获取订阅之前的1个数据
    >  *  ReplaySubject能获取订阅前已经产生的所有数据
    >  *  AsyncSubject只获取最后一个数据

## RxJava1中部分实例的实现 ##

User user = new User();
    user.setAge(1);
    Observable.just(user).subscribe(new Action1<User>() {
        @Override
        public void call(User user) {
            LOG.info("justVerify just user age:{}", user.getAge());
        }
    });
    复制代码

[产生Observable的数据][Observable]  
[RxJava操作符][RxJava]  
[既是Observable又是Observer案例][Observable_Observer]  
[异步与阻塞案例][Link 14]

## RxJava2中的部分案例 ##

Observable.just(1).subscribe(new Consumer<Integer>() {
            @Override
            public void accept(Integer integer) throws Exception {
                LOG.info("accept:{}", integer);
            }
        });
    复制代码

[产生Observable的数据][Observable 1] 可以与 [产生Observable的数据][Observable] 对比下区别，大致就可以转换出过来了。

> [背压][Link 15]:如果生产太快，消费不过来该怎么办？可以反过来限制生产的速度，比如把所有生产的数据都缓存起来，消费者自己来取，比如只有有请求的时候才给数据，没有请求的数据全部扔掉

## 附录 ##

[RxJava Github wiki地址][RxJava Github wiki]

转载于:https://juejin.im/post/5d04f666f265da1b695d5c7b

[Link 1]: https://juejin.im/post/5cfd016d6fb9a07ecc447898
[ReactiveX]: https://link.juejin.im?target=http%3A%2F%2Freactivex.io%2Fintro.html
[Link 2]: https://link.juejin.im?target=http%3A%2F%2Fwww.uwanttolearn.com%2Fandroid%2Freactive-programming-android-rxjava2-hell-part1%2F
[Link 3]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2Fxitu%2Fgold-miner%2Fblob%2Fmaster%2FTODO%2Freactive-programming-android-rxjava2-hell-part1.md
[Link 4]: https://link.juejin.im?target=http%3A%2F%2Fwww.uwanttolearn.com%2Fandroid%2Fpull-vs-push-imperative-vs-reactive-reactive-programming-android-rxjava2-hell-part2%2F
[Link 5]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2Fxitu%2Fgold-miner%2Fblob%2Fmaster%2FTODO%2Fpull-vs-push-imperative-vs-reactive-reactive-programming-android-rxjava2-hell-part2.md
[Link 6]: https://link.juejin.im?target=http%3A%2F%2Fwww.uwanttolearn.com%2Fandroid%2Ffunctional-interfaces-functional-programming-and-lambda-expressions-reactive-programming-android-rxjava2-what-the-hell-is-this-part3%2F
[Link 7]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2Fxitu%2Fgold-miner%2Fblob%2Fmaster%2FTODO%2Ffunctional-interfaces-functional-programming-and-lambda-expressions-reactive-programming-android-rxjava2-what-the-hell-is-this-part3.md
[Link 8]: https://link.juejin.im?target=http%3A%2F%2Fwww.uwanttolearn.com%2Fandroid%2Fwar-learning-curve-rx-java-2-java-8-stream-android-rxjava2-hell-part4%2F
[Link 9]: https://juejin.im/post/58f44a705c497d006c95436b
[Link 10]: https://link.juejin.im?target=http%3A%2F%2Fwww.uwanttolearn.com%2Fandroid%2Fdialogue-rx-observable-developer-android-rxjava2-hell-part5%2F
[just]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2Fmaokitty%2FSourceCodeTrace%2Fblob%2Fmaster%2Fsrc%2Fmain%2Fjava%2Fpaxi%2Fmaokitty%2Fsource%2Frxjava2%2FObservableJustTrace.java
[Link 11]: https://link.juejin.im?target=http%3A%2F%2Fwww.uwanttolearn.com%2Fandroid%2Fcontinuation-summer-vs-winter-observable-dialogue-rx-observable-developer-android-rxjava2-hell-part6%2F
[Link 12]: https://link.juejin.im?target=https%3A%2F%2Fwww.uwanttolearn.com%2Fandroid%2Fcontinuation-observable-marriage-proposal-observer-dialogue-rx-observable-developer-android-rxjava2-hell-part7%2F
[Link 13]: https://link.juejin.im?target=https%3A%2F%2Fwww.uwanttolearn.com%2Fandroid%2Fconfusion-subject-observable-observer-android-rxjava2-hell-part8%2F
[Observable]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2Fmaokitty%2FjavaVerify%2Fblob%2Fmaster%2Fhystrix%2Frxjava1%2Fsrc%2Fmain%2Fjava%2Fpaxi%2Fmaokitty%2Fverify%2FMakeThingsObservableVerify.java
[RxJava]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2Fmaokitty%2FjavaVerify%2Fblob%2Fmaster%2Fhystrix%2Frxjava1%2Fsrc%2Fmain%2Fjava%2Fpaxi%2Fmaokitty%2Fverify%2FOperatorVerify.java
[Observable_Observer]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2Fmaokitty%2FjavaVerify%2Fblob%2Fmaster%2Fhystrix%2Frxjava1%2Fsrc%2Fmain%2Fjava%2Fpaxi%2Fmaokitty%2Fverify%2FSubjectVerify.java
[Link 14]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2Fmaokitty%2FjavaVerify%2Fblob%2Fmaster%2Fhystrix%2Frxjava1%2Fsrc%2Fmain%2Fjava%2Fpaxi%2Fmaokitty%2Fverify%2FBlockObservableVerify.java
[Observable 1]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2Fmaokitty%2FjavaVerify%2Fblob%2Fmaster%2Frxjava2%2Fsrc%2Fmain%2Fjava%2Fpaxi%2Fmaokitty%2Fverify%2FObservableVerify.java
[Link 15]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2FReactiveX%2FRxJava%2Fwiki%2FBackpressure
[RxJava Github wiki]: https://link.juejin.im?target=https%3A%2F%2Fgithub.com%2FReactiveX%2FRxJava%2Fwiki