来自 reactor.core.publisher.MonoFlatMap 的 NPE

Question

我想将 JPA 存储库创建到反应式 JHipster 项目中。我试过这个：

    private ActivePairsSearchRepository activePairsSearchRepository;

    public ActivePairsSearchResource(){
    }

    public ActivePairsSearchResource(ActivePairsSearchRepository activePairsSearchRepository) {
        this.activePairsSearchRepository = activePairsSearchRepository;
    }

    @GetMapping("/active-pairs")
    public Page<?> getAllActivePairs(
        @Valid ActivePairsSearchParams params,
        Pageable pageable,
    ) {

        Specification<ActivePairs> spec = (root, query, cb) -> {
            List<Predicate> predicates = new ArrayList<>();
            if (params.getExchangeId() != null) {
                predicates.add(cb.equal(root.get("exchangeId"), params.getExchangeId()));
            }

            return cb.and(predicates.toArray(new Predicate[predicates.size()]));
        };
        return activePairsSearchRepository.findAll(pageable);
    }

存储库：

@Repository
public interface ActivePairsSearchRepository extends JpaRepository<ActivePairs, Long>, JpaSpecificationExecutor<ActivePairs> {

}

但是我得到这个错误堆栈：

java.lang.NullPointerException: null
        at io.console.web.rest.ActivePairsSearchResource.getAllActivePairs(ActivePairsSearchResource.java:63) ~[classes/:na]
        Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Assembly trace from producer [reactor.core.publisher.MonoFlatMap] :
        reactor.core.publisher.Mono.flatMap(Mono.java:2859)
        org.springframework.web.reactive.result.method.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:137)
Error has been observed at the following site(s):
        |_  Mono.flatMap ⇢ at org.springframework.web.reactive.result.method.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:137)
        |_    Mono.defer ⇢ at org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerAdapter.handle(RequestMappingHandlerAdapter.java:199)
        |_     Mono.then ⇢ at org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerAdapter.handle(RequestMappingHandlerAdapter.java:199)
        |_ Mono.doOnNext ⇢ at org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerAdapter.handle(RequestMappingHandlerAdapter.java:200)
        |_ Mono.doOnNext ⇢ at org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerAdapter.handle(RequestMappingHandlerAdapter.java:201)
Stack trace:
                at io.console.web.rest.ActivePairsSearchResource.getAllActivePairs(ActivePairsSearchResource.java:63) ~[classes/:na]
                at io.console.web.rest.ActivePairsSearchResource$$FastClassBySpringCGLIB$$a60b6277.invoke(<generated>) ~[classes/:na]
                at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.3.5.jar:5.3.5]
                at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:779) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:750) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:64) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:750) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:89) ~[spring-aop-5.3.5.jar:5.3.5]
                at io.console.aop.logging.LoggingAspect.logAround(LoggingAspect.java:105) ~[classes/:na]
                at jdk.internal.reflect.GeneratedMethodAccessor69.invoke(Unknown Source) ~[na:na]
                at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
                at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
                at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:634) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:624) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:72) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:750) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:750) ~[spring-aop-5.3.5.jar:5.3.5]
                at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:692) ~[spring-aop-5.3.5.jar:5.3.5]
                at io.console.web.rest.ActivePairsSearchResource$$EnhancerBySpringCGLIB$dd0e2ac.getAllActivePairs(<generated>) ~[classes/:na]
                at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
                at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
                at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
                at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
                at org.springframework.web.reactive.result.method.InvocableHandlerMethod.lambda$invoke[=13=](InvocableHandlerMethod.java:146) ~[spring-webflux-5.3.5.jar:5.3.5]
                at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:125) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1815) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoZip$ZipCoordinator.signal(MonoZip.java:251) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoZip$ZipInner.onNext(MonoZip.java:336) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onNext(MonoPeekTerminal.java:180) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onNext(FluxDefaultIfEmpty.java:100) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2397) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.request(FluxDefaultIfEmpty.java:76) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.request(MonoPeekTerminal.java:139) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoZip$ZipInner.onSubscribe(MonoZip.java:325) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onSubscribe(MonoPeekTerminal.java:152) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onSubscribe(FluxDefaultIfEmpty.java:90) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Mono.subscribe(Mono.java:4099) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoZip.subscribe(MonoZip.java:128) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:154) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:157) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:73) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:281) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:860) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:127) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onNext(MonoPeekTerminal.java:180) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2397) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.request(MonoPeekTerminal.java:139) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.request(FluxMapFuseable.java:169) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2193) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:2067) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onSubscribe(FluxMapFuseable.java:96) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onSubscribe(MonoPeekTerminal.java:152) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Mono.subscribe(Mono.java:4099) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:448) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:218) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:164) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:86) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Mono.subscribe(Mono.java:4099) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:81) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onComplete(MonoPeekTerminal.java:299) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onComplete(MonoPeekTerminal.java:299) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:148) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:73) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onNext(FluxFilterFuseable.java:118) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onNext(FluxDefaultIfEmpty.java:100) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:281) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:860) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1815) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoFlatMap$FlatMapInner.onNext(MonoFlatMap.java:249) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onNext(FluxDefaultIfEmpty.java:100) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:127) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onNext(FluxFilterFuseable.java:118) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxMapFuseable$MapFuseableConditionalSubscriber.onNext(FluxMapFuseable.java:295) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableConditionalSubscriber.onNext(FluxFilterFuseable.java:337) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1815) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:151) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onNext(FluxFilterFuseable.java:118) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2397) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.request(FluxFilterFuseable.java:191) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoFlatMap$FlatMapMain.onSubscribe(MonoFlatMap.java:110) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onSubscribe(FluxFilterFuseable.java:87) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoCurrentContext.subscribe(MonoCurrentContext.java:36) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:157) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:127) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onNext(FluxFilterFuseable.java:118) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxPeekFuseable$PeekFuseableConditionalSubscriber.onNext(FluxPeekFuseable.java:503) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:73) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onNext(FluxFilterFuseable.java:118) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFlatMap$FlatMapMain.tryEmitScalar(FluxFlatMap.java:488) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFlatMap$FlatMapMain.onNext(FluxFlatMap.java:421) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onNext(FluxPeekFuseable.java:210) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable$IterableSubscription.slowPath(FluxIterable.java:270) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable$IterableSubscription.request(FluxIterable.java:228) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.request(FluxPeekFuseable.java:144) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFlatMap$FlatMapMain.onSubscribe(FluxFlatMap.java:371) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onSubscribe(FluxPeekFuseable.java:178) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:164) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:86) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Mono.subscribe(Mono.java:4099) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:448) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:218) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:164) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:86) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Mono.subscribe(Mono.java:4099) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:173) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Mono.subscribe(Mono.java:4099) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:81) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onComplete(FluxFilterFuseable.java:171) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxPeekFuseable$PeekFuseableConditionalSubscriber.onComplete(FluxPeekFuseable.java:595) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:84) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2399) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2193) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:2067) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Mono.subscribe(Mono.java:4099) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:81) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoNext$NextSubscriber.onComplete(MonoNext.java:102) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onComplete(FluxFilterFuseable.java:171) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFlatMap$FlatMapMain.checkTerminated(FluxFlatMap.java:846) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFlatMap$FlatMapMain.drainLoop(FluxFlatMap.java:608) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFlatMap$FlatMapMain.drain(FluxFlatMap.java:588) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFlatMap$FlatMapMain.onComplete(FluxFlatMap.java:465) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onComplete(FluxPeekFuseable.java:277) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable$IterableSubscription.slowPath(FluxIterable.java:292) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable$IterableSubscription.request(FluxIterable.java:228) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.request(FluxPeekFuseable.java:144) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFlatMap$FlatMapMain.onSubscribe(FluxFlatMap.java:371) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onSubscribe(FluxPeekFuseable.java:178) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:164) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:86) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:157) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1815) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxDefaultIfEmpty$DefaultIfEmptySubscriber.onComplete(FluxDefaultIfEmpty.java:108) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onComplete(FluxMapFuseable.java:150) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onComplete(FluxMapFuseable.java:150) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxFilterFuseable$FilterFuseableSubscriber.onComplete(FluxFilterFuseable.java:171) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxMapFuseable$MapFuseableConditionalSubscriber.onComplete(FluxMapFuseable.java:344) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1816) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoCacheTime$CoordinatorSubscriber.signalCached(MonoCacheTime.java:337) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.MonoCacheTime$CoordinatorSubscriber.onNext(MonoCacheTime.java:354) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onNext(FluxPeekFuseable.java:210) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:73) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.publisher.FluxSubscribeOnCallable$CallableSubscribeOnSubscription.run(FluxSubscribeOnCallable.java:251) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:68) ~[reactor-core-3.4.4.jar:3.4.4]
                at reactor.core.scheduler.SchedulerTask.call(SchedulerTask.java:28) ~[reactor-core-3.4.4.jar:3.4.4]
                at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
                at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[na:na]
                at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
                at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
                at java.base/java.lang.Thread.run(Thread.java:829) ~[na:na]

你知道我该如何解决这个问题吗？

Answer 1

你可以试试这个：

@GetMapping("/active-pairs")
public Page<?> getAllActivePairs(@Valid ActivePairsSearchParams params, Pageable pageable) {
    Specification<ActivePairs> activePairsSpecification = createSpecification(params);
    return activePairsSearchRepository.findAll(activePairsSpecification, pageable);
} 

private Specification<ActivePairs> createSpecification(ActivePairsSearchParams params) {
    return (root, query, cb) -> {
        Predicate conjunction = cb.conjunction();
        if (params.getExchangeId() != null) {
            conjunction = cb.add(conjunction, cb.add(cb.equal(root.get("exchangeId"), params.getExchangeId())));
        }
        return conjunction;
    }
}

来自 reactor.core.publisher.MonoFlatMap 的 NPE

NPE from reactor.core.publisher.MonoFlatMap

java

spring

spring-boot

jhipster