带有 Mono.empty() 参数的反应式 Java Mono.zip [英] Reactive Java Mono.zip with Mono.empty() parameters
本文介绍了带有 Mono.empty() 参数的反应式 Java Mono.zip的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
使用 Spring 和 Reactor 项目将多个 api 调用压缩为聚合结果.Mono.zip() 和 Mono.empty() 参数可以返回空结果吗?
Using Spring with Reactor Project to zip multiple api calls as aggregated result. Can Mono.zip() with Mono.empty() parameters return null result?
Mono<Dog> dogMono = dogApiClient.getDog(); // can return Mono.empty()
Mono<Cat> catMono = catMono = catApiClient.getCat(); // can returnMono.empty()
Mono<Horse> horseMono = horseApiClient.getHorse(); // can return Mono.empty()
Mono.zip(dogMono, dogMobo, horseMono)
.map(this::mapToAnimals);
预期结果:
{
dog: null, // if dog is null
cat: null, // if cat is null
horse: null, // if horse is null
}
实际结果:
{
dog: {
name: null,
surname: null
},
cat: {
name: null,
surname: null
},
horse: {
name: null,
surname: null
}
}
或
"" // empty
推荐答案
好吧,这当然不是一个优雅的解决方案,但您可以选择将您的值包装在 Optional 中:
Well, it's certainly not an elegant solution, but you can choose to wrap your values inside Optional:
Mono<Optional<Dog>> dogMono = Mono.just(Optional.empty());
if(condition1) {
dogMono = dogApiClient.getDog().map(Optional::of);
}
Mono<Optional<Cat>> catMono = Mono.just(Optional.empty());
if(condition2) {
catMono = catApiClient.getCat().map(Optional::of);
}
Mono<Optional<Horse>> horseMono = Mono.just(Optional.empty());
if(condition3) {
horseMono = horseApiClient.getHorse().map(Optional::of);
}
Mono.zip(dogMono, catMono, horseMono)
.map(this::mapToAnimals);
private Output mapToAnimals(Tuple3<Optional<Dog>, Optional<Cat>, Optional<Horse>> tuple3)
{
Dog dog = tuple3.getT1().orElse(null);
Cat cat = tuple3.getT2().orElse(null);
Horse horse = tuple3.getT3().orElse(null);
return new Output(dog, cat, horse);
}
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