Feign 客户端无法与云网关配合使用？抛出异常：java.lang.IllegalStateException：block()/blockFirst()/blockLast() 正在阻塞

问题描述 投票：0回答：1

使用Spring Boot 3.1.3版本构建一个简单的微服务，它有两个服务，一个是api-gateway，另一个是fisherman-service。 API-Gateway 使用 cloud-gateway、eureka-cient 和 openfeign，fisherman-service 是一个已公开某些 REST 端点的 Spring Boot 应用程序。在尝试通过 feign-client 服务访问 Fisherman-service 时，出现异常。

pom.xml - Feign 客户端

<?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.1.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.techverse</groupId>
    <artifactId>api-gateway-with-feign-and-eureka</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>api-gateway-with-feign-and-eureka</name>
    <description>api-gateway-with-feign-and-eureka</description>
    <properties>
        <java.version>17</java.version>
        <spring-cloud.version>2022.0.4</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

application.yml 文件：Feign Client

server:
  port: 8089
  
spring:
  application:
    name: api-gateway-3
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true

eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

应用程序文件：Feign-Client

@EnableFeignClients
@SpringBootApplication
@EnableDiscoveryClient
public class ApiGatewayWithFeignAndEurekaApplication {

    public static void main(String[] args) {
        SpringApplication.run(ApiGatewayWithFeignAndEurekaApplication.class, args);
    }

}

Feign-客户端接口

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.*;

@FeignClient(name = "FISHERMAN-SERVICE")
public interface FishermanClient {

    @GetMapping("fm/msg")
    String msg();
}

Feign-Client 控制器类

@RequestMapping(path = "/feign")
@RestController
public class FismermanCallingController {

    @Autowired
    private FishermanClient fishermanClient;

    @GetMapping("/msg")
    public String msg(){
        String msg = fishermanClient.msg();
        return msg;
    }
}

渔民服务控制器类：

@RestController
@RequestMapping(path = "/fm")
public class FishermanController {

    private FishermanService fishermanService;

    @Autowired
    FishermanController(FishermanService fishermanService) {
        this.fishermanService = fishermanService;
    }

    @GetMapping("/msg")
    public String msg(){
        return "Hello from Fisherman Service";
    }
}

fisherman 服务已在端口 8082 上启动并运行，并在从邮递员或 chrome 访问 uri 时给出正确的响应。

URI：本地主机：8082/fm/msg

回复：渔民服务中心您好

但是当我们尝试通过 feign 客户端访问相同的内容时，我们会遇到异常。

URI：本地主机：8089/feign/msg

例外：

2023-09-02T20:56:56.287+05:30 ERROR 7944 --- [ctor-http-nio-7] a.w.r.e.AbstractErrorWebExceptionHandler : [72f710ac-3]  500 Server Error for HTTP GET "/feign/msg"

java.lang.IllegalStateException: block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-nio-7
    at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:86) ~[reactor-core-3.5.9.jar:3.5.9]
    Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
    *__checkpoint ⇢ org.springframework.cloud.gateway.filter.WeightCalculatorWebFilter [DefaultWebFilterChain]
    *__checkpoint ⇢ HTTP GET "/feign/msg" [ExceptionHandlingWebHandler]
Original Stack Trace:
        at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:86) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.Mono.block(Mono.java:1712) ~[reactor-core-3.5.9.jar:3.5.9]
        at org.springframework.cloud.loadbalancer.blocking.client.BlockingLoadBalancerClient.choose(BlockingLoadBalancerClient.java:163) ~[spring-cloud-loadbalancer-4.0.4.jar:4.0.4]
        at org.springframework.cloud.openfeign.loadbalancer.FeignBlockingLoadBalancerClient.execute(FeignBlockingLoadBalancerClient.java:118) ~[spring-cloud-openfeign-core-4.0.4.jar:4.0.4]
        at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:100) ~[feign-core-12.4.jar:na]
        at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:70) ~[feign-core-12.4.jar:na]
        at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:96) ~[feign-core-12.4.jar:na]
        at jdk.proxy2/jdk.proxy2.$Proxy109.msg(Unknown Source) ~[na:na]
        at com.techverse.apigatewaywithfeignandeureka.controllers.FismermanCallingController.msg(FismermanCallingController.java:22) ~[classes/:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
        at org.springframework.web.reactive.result.method.InvocableHandlerMethod.lambda$invoke$0(InvocableHandlerMethod.java:145) ~[spring-webflux-6.0.11.jar:6.0.11]
        at reactor.core.publisher.FluxFlatMap.trySubscribeScalarMap(FluxFlatMap.java:152) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoFlatMap.subscribeOrReturn(MonoFlatMap.java:53) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:57) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.subscribeNext(MonoIgnoreThen.java:240) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.onComplete(MonoIgnoreThen.java:203) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoFlatMap$FlatMapMain.onComplete(MonoFlatMap.java:189) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.Operators.complete(Operators.java:137) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoZip.subscribe(MonoZip.java:121) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.Mono.subscribe(Mono.java:4495) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.subscribeNext(MonoIgnoreThen.java:263) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:51) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:165) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:74) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.innerNext(FluxConcatMapNoPrefetch.java:258) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:863) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:129) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onNext(MonoPeekTerminal.java:180) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2545) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.request(MonoPeekTerminal.java:139) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.request(FluxMapFuseable.java:171) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.request(Operators.java:2305) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.request(FluxConcatMapNoPrefetch.java:338) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoNext$NextSubscriber.request(MonoNext.java:108) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2341) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:2215) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoNext$NextSubscriber.onSubscribe(MonoNext.java:70) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.onSubscribe(FluxConcatMapNoPrefetch.java:164) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:201) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:83) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.Mono.subscribe(Mono.java:4495) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.subscribeNext(MonoIgnoreThen.java:263) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:51) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.core.publisher.MonoDeferContextual.subscribe(MonoDeferContextual.java:55) ~[reactor-core-3.5.9.jar:3.5.9]
        at reactor.netty.http.server.HttpServer$HttpServerHandle.onStateChange(HttpServer.java:1052) ~[reactor-netty-http-1.1.10.jar:1.1.10]
        at reactor.netty.ReactorNetty$CompositeConnectionObserver.onStateChange(ReactorNetty.java:710) ~[reactor-netty-core-1.1.10.jar:1.1.10]
        at reactor.netty.transport.ServerTransport$ChildObserver.onStateChange(ServerTransport.java:481) ~[reactor-netty-core-1.1.10.jar:1.1.10]
        at reactor.netty.http.server.HttpServerOperations.onInboundNext(HttpServerOperations.java:647) ~[reactor-netty-http-1.1.10.jar:1.1.10]
        at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:114) ~[reactor-netty-core-1.1.10.jar:1.1.10]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at reactor.netty.http.server.HttpTrafficHandler.channelRead(HttpTrafficHandler.java:238) ~[reactor-netty-http-1.1.10.jar:1.1.10]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:442) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:346) ~[netty-codec-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:318) ~[netty-codec-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:442) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:440) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:788) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:724) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:650) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562) ~[netty-transport-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.97.Final.jar:4.1.97.Final]
        at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]

并且渔夫服务已在 Eureka 服务器上正确注册，名称为“FISHERMAN-SERVICE”

spring-boot netflix-eureka spring-cloud-gateway spring-cloud-feign openfeign
1个回答
0
投票

Springgateway使用WebFlux 两种方案可以解决这个问题

  1. 使用线程调用feign
@GetMapping("/msg")
    public Mono<String> msg(){
        Future futer = //some thread to call fishermanClient.msg();   
        return Mono.just(futer.get());
    }
  1. 将 fegin 更改为 web 客户端
@GetMapping("/msg")
    public Mono<String> msg(){
        Mono<String> msg = webclient.....();
        return Mono.just(msg);
    }
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