使用 Spring WebFlux Client 使用 REST Endpoint 时出错
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【中文标题】使用 Spring WebFlux Client 使用 REST Endpoint 时出错【英文标题】:Error while consuming REST Endpoint using Spring WebFlux Client 【发布时间】:2017-09-29 11:06:00 【问题描述】:我刚刚开始使用 Spring reactor 3 (WebFlux)。当尝试使用 WebClient 来使用 REST 端点以返回 Flux 时,我遇到了以下错误。
应用类:
@Bean
public WebClient client()
return WebClient.create("http://localhost:8080");
@Bean
CommandLineRunner demo(WebClient client)
return args->
client.get().uri("/reactive/zip-code")
.accept(MediaType.APPLICATION_STREAM_JSON)
.exchange()
.flatMap(cr -> cr.bodyToFlux(ZipCode.class))
.subscribe(System.out::println);
;
build.gradle
buildscript
ext
springBootVersion = '2.0.0.BUILD-SNAPSHOT'
repositories
mavenCentral()
maven url "https://repo.spring.io/snapshot"
maven url "https://repo.spring.io/milestone"
dependencies
classpath("org.springframework.boot:spring-boot-gradle- plugin:$springBootVersion")
repositories
mavenCentral()
maven url "https://repo.spring.io/snapshot"
maven url "https://repo.spring.io/milestone"
dependencyManagement
imports
mavenBom "io.projectreactor:reactor-bom:Aluminium-SR1"
dependencies
compile('io.projectreactor:reactor-core')
compile('org.springframework.boot:spring-boot-devtools')
compile('org.springframework.boot:spring-boot-starter-webflux')
compileOnly('org.projectlombok:lombok')
testCompile('org.springframework.boot:spring-boot-starter-test')
错误:
2017-05-01 22:20:29.718 WARN 14417 --- [ctor-http-nio-2] incAbstractChannelHandlerContext:用户处理程序抛出了异常“”[为完整堆栈跟踪启用调试级别]处理以下异常时的 exceptionCaught() 方法:
java.lang.NoSuchMethodError: reactor.core.publisher.Flux.onErrorMap(Ljava/util/function/Function;)Lreactor/core/publisher/Flux;
at org.springframework.http.codec.DecoderHttpMessageReader.read(DecoderHttpMessageReader.java:93) ~[spring-web-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT]
at org.springframework.web.reactive.function.BodyExtractors.lambda$null$2(BodyExtractors.java:120) ~[spring-webflux-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT]
at java.util.Optional.map(Optional.java:215) ~[na:1.8.0_111]
at org.springframework.web.reactive.function.BodyExtractors.readWithMessageReaders(BodyExtractors.java:183) ~[spring-webflux-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT]
at org.springframework.web.reactive.function.BodyExtractors.lambda$toFlux$3(BodyExtractors.java:111) ~[spring-webflux-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT]
at org.springframework.web.reactive.function.client.DefaultClientResponse.body(DefaultClientResponse.java:80) ~[spring-webflux-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT]
at org.springframework.web.reactive.function.client.DefaultClientResponse.bodyToFlux(DefaultClientResponse.java:105) ~[spring-webflux-5.0.0.BUILD-SNAPSHOT.jar:5.0.0.BUILD-SNAPSHOT]
at io.clapi.reactive.ReactiveApiApplication.lambda$null$0(ReactiveApiApplication.java:34) ~[main/:na]
at reactor.core.publisher.MonoFlatMap$FlattenSubscriber.onNext(MonoFlatMap.java:132) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:370) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:119) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:370) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onNext(FluxPeekFuseable.java:178) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:370) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:370) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:119) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:370) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxRetryPredicate$RetryPredicateSubscriber.onNext(FluxRetryPredicate.java:78) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:370) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:370) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.core.publisher.MonoCreate$DefaultMonoSink.success(MonoCreate.java:99) ~[reactor-core-3.0.5.RELEASE.jar:3.0.5.RELEASE]
at reactor.ipc.netty.channel.PooledClientContextHandler.fireContextActive(PooledClientContextHandler.java:84) ~[reactor-netty-0.6.1.RELEASE.jar:0.6.1.RELEASE]
at reactor.ipc.netty.http.client.HttpClientOperations.onInboundNext(HttpClientOperations.java:524) ~[reactor-netty-0.6.1.RELEASE.jar:0.6.1.RELEASE]
at reactor.ipc.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:125) ~[reactor-netty-0.6.1.RELEASE.jar:0.6.1.RELEASE]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:293) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:280) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:396) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:248) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1334) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:926) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:134) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:624) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:559) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:476) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:438) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:858) [netty-all-4.1.9.Final.jar:4.1.9.Final]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_111]
【问题讨论】:
尝试删除 compile('io.projectreactor:reactor-core')。 compile('org.springframework.boot:spring-boot-starter-webflux') 将为您获得正确版本的反应堆核心 【参考方案1】:您不应该尝试自己管理 Reactor 依赖项,它由 Spring Boot 处理。从构建文件中删除 Reactor BOM。
这来自 Spring 代码库中反映的最新 Reactor SNAPSHOT 中的 API 更改。
【讨论】:
谢谢@brian-clozel。删除 BOM 后,它起作用了。以上是关于使用 Spring WebFlux Client 使用 REST Endpoint 时出错的主要内容,如果未能解决你的问题,请参考以下文章
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