project-reactor - 带短路选项的 Flux.concatDelayError

Question

我正在使用 Flux.concatDelayError因为我想订阅多个 Monos一个一个，也想知道有没有失败。

但是，现在我也想短路如果我的 Monos 之一以特定类型的错误结束。
这很容易吗？

Answer 1

使用 onErrorResume运算符，您可以配置一个条件回退到 Mono.empty()对于每个单声道:

package com.example;

import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import static java.util.function.Predicate.not;

public class ReactorExample
{
    public static void main(String[] args)
    {
        Mono<String> mono = Mono.just("first").doOnNext(a -> System.out.println(a + " was called."));

        Mono<String> mono2 = Mono.<String>error(new RuntimeException("Not terminating error."))
                .onErrorResume(not(ShortCircuitingException.class::isInstance), e -> Mono.empty());

        Mono<String> mono3 = Mono.just("third").doOnNext(a -> System.out.println(a + " was called."));

        Mono<String> mono4 = Mono.<String>error(new ShortCircuitingException())
                                 .onErrorResume(not(ShortCircuitingException.class::isInstance), e -> Mono.empty());

        Mono<String> mono5 = Mono.just("fifth").doOnNext(a -> System.out.println(a + " was called."));

        Flux.concat(mono, mono2, mono3, mono4, mono5)
            .collectList()
            .block();
    }

    private static class ShortCircuitingException extends RuntimeException
    {
    }
}

输出:

first was called.
third was called.
Exception in thread "main" com.example.ReactorExample$ShortCircuitingException