RxJava2 Flowable do (辅助操作符)

1 do系列接口的作用

do系列的接口作用是在项目发布的的生命周期中，onNext、onComplete、onError被调用的时候调用，有点类似于观察源Publisher的序列调用生命周期，当某个点被调用的时候做一些事情

2 do接口

`Flowable<T>`	`doAfterNext(Consumer<? super T> onAfterNext)` Calls the specified consumer with the current item after this item has been emitted to the downstream. 调用当前项目指定的Consumer，在这个项目被发布到下游之后 (优化一下翻译) 在项目被发布到下游之后，调用当前项目指定的Consumer
`Flowable<T>`	`doAfterTerminate(Action onAfterTerminate)` Registers an `Action` to be called when this Publisher invokes either `onComplete` or `onError`. 当此Publisher调用onComplete或onError时，注册要调用的Action。
`Flowable<T>`	`doFinally(Action onFinally)` Calls the specified action after this Flowable signals onError or onCompleted or gets canceled by the downstream. 在此Flowable发出onError或onCompleted通知后之后调用指定的操作，或者由下游取消。（翻译说明：signal v：发信号，onError和onCompleted是通知的两种类型）
`Flowable<T>`	`doOnCancel(Action onCancel)` Calls the cancel `Action` if the downstream cancels the sequence. 如果下游取消序列，则调用取消操作。
`Flowable<T>`	`doOnComplete(Action onComplete)` Modifies the source Publisher so that it invokes an action when it calls `onComplete`. 修改源发布服务器，以便在调用onComplete时调用操作。
`Flowable<T>`	`doOnEach(Consumer<? super Notification<T>> onNotification)` Modifies the source Publisher so that it invokes an action for each item it emits. 修改源发布服务器，以便为其发出的每个项调用操作。
`Flowable<T>`	`doOnEach(Subscriber<? super T> subscriber)` Modifies the source Publisher so that it notifies a Subscriber for each item and terminal event it emits. 修改源发布服务器，以便它通知订阅服务器它发出的每个项目和终端事件。
`Flowable<T>`	`doOnError(Consumer<? super Throwable> onError)` Modifies the source Publisher so that it invokes an action if it calls `onError`. 修改源Publisher，以便在调用onError时调用它。
`Flowable<T>`	`doOnLifecycle(Consumer<? super Subscription> onSubscribe, LongConsumer onRequest,Action onCancel)` Calls the appropriate onXXX method (shared between all Subscribers) for the lifecycle events of the sequence (subscription, cancellation, requesting). 调用适当的onXXX方法（在所有订阅者之间共享）以获取序列的生命周期事件（订阅，取消，请求）。
`Flowable<T>`	`doOnNext(Consumer<? super T> onNext)` Modifies the source Publisher so that it invokes an action when it calls `onNext`. 修改源Publisher，以便它在调用onNext时调用操作。
`Flowable<T>`	`doOnRequest(LongConsumer onRequest)` Modifies the source `Publisher` so that it invokes the given action when it receives a request for more items.
`Flowable<T>`	`doOnSubscribe(Consumer<? super Subscription> onSubscribe)` Modifies the source `Publisher` so that it invokes the given action when it is subscribed from its subscribers. 修改源发布服务器，以便在从订阅服务器订阅时调用给定的操作。
`Flowable<T>`	`doOnTerminate(Action onTerminate)` Modifies the source Publisher so that it invokes an action when it calls `onComplete` or `onError`. 修改源Publisher，以便它在调用onComplete或onError时调用操作。

3 do图解说明

RxJava2 Flowable do (辅助操作符)

4 测试用例

下面测试用例列举了接口中的部分，但是已经可以很容易看出doXXX的作用了


    @Test
    public void doAfterNext() {
        System.out.println("######doAfterNext#####");
        Flowable.just("item1", "item2")
                .doOnNext(new Consumer<String>() {
                    @Override
                    public void accept(String s) throws Exception {
                        System.out.println("doOnNext,s=" + s);
                    }
                })
                .doAfterNext(new Consumer<String>() {
                    @Override
                    public void accept(String s) throws Exception {
                        System.out.println("doAfterNext,s=" + s +"\n");
                    }
                })
                .doOnComplete(new Action() {
                    @Override
                    public void run() throws Exception {
                        System.out.println("#doOnComplete#");
                    }
                })
                .doOnEach(new Consumer<Notification<String>>() {
                    @Override
                    public void accept(Notification<String> stringNotification) throws Exception {
                        System.out.println("doOnEach,stringNotification" + stringNotification.toString());
                    }
                })
                .doOnTerminate(new Action() {
                    @Override
                    public void run() throws Exception {
                        System.out.println("#doOnTerminate#");
                    }
                })
                .doAfterTerminate(new Action() {
                    @Override
                    public void run() throws Exception {
                        System.out.println("#doAfterTerminate#");
                    }
                })
                .doOnSubscribe(new Consumer<Subscription>() {
                    @Override
                    public void accept(Subscription subscription) throws Exception {
                        System.out.println("doOnSubscribe,subscription=" + subscription.toString());
                    }
                })
                .doFinally(new Action() {
                    @Override
                    public void run() throws Exception {
                        System.out.println("#doFinally#");
                    }
                })
                .subscribe(new Consumer<String>() {
                    @Override
                    public void accept(String s) throws Exception {
                        System.out.println("subscribe,s=" + s);
                    }
                });
    }

测试输出
######doAfterNext#####
doOnSubscribe,subscription=io.reactivex.internal.operators.flowable.FlowableDoOnEach$DoOnEachSubscriber@b684286
doOnNext,s=item1
doOnEach,stringNotificationOnNextNotification[item1]
subscribe,s=item1
doAfterNext,s=item1

doOnNext,s=item2
doOnEach,stringNotificationOnNextNotification[item2]
subscribe,s=item2
doAfterNext,s=item2

#doOnComplete#
doOnEach,stringNotificationOnCompleteNotification
#doOnTerminate#
#doFinally#
#doAfterTerminate#

RxJava2 Flowable do (辅助操作符)

1 do系列接口的作用

2 do接口

3 do图解说明

4 测试用例

相关推荐