我正在尝试使用 Feign 客户端。以下是我的客户:
import com.eprogrammerz.examples.domain.Movie;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
/**
* Created by Yogen on 12/26/2016.
*/
@FeignClient(name = "movie-api")
public interface MovieApi {
@RequestMapping(method = RequestMethod.GET, value = "/movies/{id}")
Movie getMovie(@PathVariable("id") Long id);
}
我从简单的服务中调用它,如下所示:
@Service
public class MovieService {
@Autowired
MovieApi movieApi;
public Movie findMovie(Long id){
Movie movieOfTheDay = movieApi.getMovie(id);
return movieOfTheDay;
}
}
我的 spring boot 应用程序如下:
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
@EnableFeignClients(basePackages = {"com.eprogrammerz.examples"})
@EnableCircuitBreaker
@SpringBootApplication
public class ClientAppApplication {
public static void main(String[] args) {
SpringApplication.run(ClientAppApplication.class, args);
}
}
build.gradle
buildscript {
ext {
springBootVersion = '1.4.3.RELEASE'
}
repositories {
jcenter()
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
jar {
baseName = 'client-app'
version = '0.0.1-SNAPSHOT'
}
sourceCompatibility = 1.8
targetCompatibility = 1.8
repositories {
jcenter()
mavenCentral()
maven { url "https://repo.spring.io/snapshot" }
maven { url "https://repo.spring.io/milestone" }
}
dependencies {
compile('org.springframework.cloud:spring-cloud-starter-feign')
// https://mvnrepository.com/artifact/com.netflix.hystrix/hystrix-core
compile('org.springframework.cloud:spring-cloud-starter-hystrix')
compile("org.springframework.boot:spring-boot-starter-web"){
exclude group: 'org.springframework.boot', module: 'spring-boot-starter-logging'
}
compileOnly('org.projectlombok:lombok')
testCompile('org.springframework.boot:spring-boot-starter-test')
}
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-dependencies:Camden.BUILD-SNAPSHOT"
mavenBom "org.springframework.boot:spring-boot-starter-parent:${springBootVersion}"
}
}
我收到如下错误:
2016-12-30 13:07:16.894 INFO 6748 --- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization completed in 39 ms
2016-12-30 13:07:16.939 INFO 6748 --- [nio-8082-exec-1] c.e.e.controllers.RequestController : Calling findMovie(1203)
2016-12-30 13:07:17.240 INFO 6748 --- [rix-movie-api-1] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@547496c2: startup date [Fri Dec 30 13:07:17 EST 2016]; parent: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@542e560f
2016-12-30 13:07:17.318 INFO 6748 --- [rix-movie-api-1] f.a.AutowiredAnnotationBeanPostProcessor : JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
2016-12-30 13:07:17.619 INFO 6748 --- [rix-movie-api-1] c.netflix.config.ChainedDynamicProperty : Flipping property: movie-api.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2016-12-30 13:07:17.670 INFO 6748 --- [rix-movie-api-1] c.n.u.concurrent.ShutdownEnabledTimer : Shutdown hook installed for: NFLoadBalancer-PingTimer-movie-api
2016-12-30 13:07:17.727 INFO 6748 --- [rix-movie-api-1] c.netflix.loadbalancer.BaseLoadBalancer : Client:movie-api instantiated a LoadBalancer:DynamicServerListLoadBalancer:{NFLoadBalancer:name=movie-api,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2016-12-30 13:07:17.739 INFO 6748 --- [rix-movie-api-1] c.n.l.DynamicServerListLoadBalancer : Using serverListUpdater PollingServerListUpdater
2016-12-30 13:07:17.746 INFO 6748 --- [rix-movie-api-1] c.n.l.DynamicServerListLoadBalancer : DynamicServerListLoadBalancer for client movie-api initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=movie-api,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:com.netflix.loadbalancer.ConfigurationBasedServerList@45bcfd5
2016-12-30 13:07:18.191 ERROR 6748 --- [nio-8082-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is com.netflix.hystrix.exception.HystrixRuntimeException: MovieApi#getMovie(Long) failed and no fallback available.] with root cause
com.netflix.client.ClientException: Load balancer does not have available server for client: movie-api
at com.netflix.loadbalancer.LoadBalancerContext.getServerFromLoadBalancer(LoadBalancerContext.java:468) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:184) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:180) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:94) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:42) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber$1.call(OperatorRetryWithPredicate.java:127) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.enqueue(TrampolineScheduler.java:73) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.schedule(TrampolineScheduler.java:52) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:79) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:45) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.util.ScalarSynchronousObservable$WeakSingleProducer.request(ScalarSynchronousObservable.java:276) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Subscriber.setProducer(Subscriber.java:209) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:138) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:129) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.subscribe(Observable.java:10307) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.subscribe(Observable.java:10274) ~[rxjava-1.1.10.jar:1.1.10]
at rx.observables.BlockingObservable.blockForSingle(BlockingObservable.java:445) ~[rxjava-1.1.10.jar:1.1.10]
at rx.observables.BlockingObservable.single(BlockingObservable.java:342) ~[rxjava-1.1.10.jar:1.1.10]
at com.netflix.client.AbstractLoadBalancerAwareClient.executeWithLoadBalancer(AbstractLoadBalancerAwareClient.java:102) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at org.springframework.cloud.netflix.feign.ribbon.LoadBalancerFeignClient.execute(LoadBalancerFeignClient.java:63) ~[spring-cloud-netflix-core-1.2.4.BUILD-SNAPSHOT.jar:1.2.4.BUILD-SNAPSHOT]
at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:97) ~[feign-core-9.3.1.jar:na]
at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:76) ~[feign-core-9.3.1.jar:na]
at feign.hystrix.HystrixInvocationHandler$1.run(HystrixInvocationHandler.java:108) ~[feign-hystrix-9.3.1.jar:na]
at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:301) ~[hystrix-core-1.5.6.jar:1.5.6]
at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:297) ~[hystrix-core-1.5.6.jar:1.5.6]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:46) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorSubscribeOn$1.call(OperatorSubscribeOn.java:94) ~[rxjava-1.1.10.jar:1.1.10]
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:56) ~[hystrix-core-1.5.6.jar:1.5.6]
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:47) ~[hystrix-core-1.5.6.jar:1.5.6]
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:69) ~[hystrix-core-1.5.6.jar:1.5.6]
at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55) ~[rxjava-1.1.10.jar:1.1.10]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[na:1.8.0_51]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_51]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) ~[na:1.8.0_51]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) ~[na:1.8.0_51]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_51]
我尝试了不同的方式。但无法找出解决方案。我在 Spring Cloud Netflix 上也找不到任何关于此的信息。我也找不到关于 StackOverflow discussion thread 的任何信息。
我在这里缺少什么? TIA.
更多详情:
movie-api微服务的application.yml如下:
server:
port: 8090
logging:
config: classpath:log4j2.yml
spring:
application:
name: movie-api
movie-api 模块上的 Spring Boot 应用程序:
@SpringBootApplication
public class MovieApiApplication {
public static void main(String[] args) {
SpringApplication.run(MovieApiApplication.class, args);
}
}
控制器如下:
@RestController
@Slf4j
public class MovieController {
@Autowired
private MovieRepository movieRepository;
@RequestMapping("/movies/{id}")
public ResponseEntity<Movie> getBook(@PathVariable("id") Long id){
log.trace("getBook({})",id);
Optional<Movie> movie = Optional.of(movieRepository.findOneById(id));
if(movie.isPresent())
return new ResponseEntity(movie.get(), HttpStatus.OK);
return new ResponseEntity<Movie>(HttpStatus.NOT_FOUND);
}
}
经过研究,在@Bloodysock 的帮助下,我发现我在“client-app”微服务中缺少远程服务器的注册。该文档位于Spring Cloud Netflix.
我在“
application.yml
”微服务的client-app
中使用没有Eureka的Ribbon配置为:
movie-api:
ribbon:
listOfServers: http://localhost:8090
问题是您的服务不知道所请求服务的主机。如果您使用的是 Eureka,请将此行放在您的 .properties 文件中:
eureka.client.fetchRegistry=true
或 .yml 文件:
eureka:
client:
fetch-registry: true
它将使您的服务与 Eureka 对话并发现所请求服务的主机。
我几乎浪费了2个小时来寻找根本原因。我错误地在客户端应用程序中导入了 EnableEurekaClient,这是问题的根本原因。我终于通过删除导入解决了这个问题。令我惊讶的是 @EnableDiscoveryClient 不需要以下依赖项。 但是,如果您使用的是 Eureka 命名服务器,则必须使用它。
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
<version>2.0.0.RELEASE</version>
</dependency>
如果您的 Spring Cloud 设置不支持在 application.properties/application.yml 中指定服务器,您必须在配置类中配置服务 URL。
请注意我的 application.properties 中的警告消息 [Spring Boot v2.0.0RELEASE, spring-cloud-starter-feign & spring-cloud-starter-ribbon v 1.4.3.RELEASE]
所以我所做的就是编写如下配置类:
@Configuration
class LocalRibbonClientConfiguration {
@Bean
public ServerList<Server> ribbonServerList() {
// return new ConfigurationBasedServerList();
StaticServerList<Server> staticServerList = new StaticServerList<>((new Server("localhost", 8001)),
new Server("localhost", 8000));
return staticServerList;
}
}
然后,将 Spring Boot 应用程序配置为使用此配置,如下所示:
@SpringBootApplication
@EnableFeignClients("my-package.currencyconversionservice")
@RibbonClient(name = "currency-conversion-service", configuration = LocalRibbonClientConfiguration.class)
public class CurrencyConversionServiceApplication {
// nothing new here...
}
无需更改Feign Proxy类。发布只是为了让这篇文章成为问题的完整解决方案:
@FeignClient(name="currency-exchange-service")
@RibbonClient(name="currency-exchange-service")
public interface CurrencyExchangeServiceProxy {
@GetMapping("/currency-exchange/from/{from}/to/{to}")
public CurrencyConversionBean retrieveExchangeValue(@PathVariable("from") String from, @PathVariable("to") String to);
}
就是这样。问题已解决。
在 Zuul Gateway 的 application.properties 文件中添加这一行。
movie-api.ribbon.listOfServers=http://localhost:8080
总的来说—— {{服务名称}}.ribbon.listOfServers={{服务网址}}
这对我有用。
问题是你的服务不知道所请求服务的主机。如果您使用 Eureka 和 zuul,请将此行放在您的 zuul .properties 或 .yml 文件中:
eureka.client.fetch-registry=true
好像
ClientAppApplication
不知道你的尤里卡服务器地址。
你可以检查你的 applation.yml
eureka
instance:
hostname: cloud-feignorder-consume
client:
register-with-eureka: false #default true
fetch-registry: true #default true
最后一行你应该检查属性'eureka.client.fetch-registry'。它应该是 true 或不签名。然后你的客户端可以从 eureka 服务器获取服务器列表。
在没有 eureka 的情况下,在客户端应用程序中,如果您没有 application.yml 而不是 application.properties 文件,那么您可以在客户端应用程序重新启动之前如下设置属性:
currency-exchange-service.ribbon.listOfServers : http://localhost:8000,http://localhost:8001
我遇到过这个错误,我想补充一下我对这个问题的贡献,因为这是谷歌返回的第一个错误。希望对您有所帮助。
我的项目使用了 Spring Boot
2.3.4.REALEASE
和 Eureka Client 3.1.3
。
解决我的问题的方法是将 Eureka 客户端切换到版本2.1.6.RELEASE
.
我相信由于某种原因,最新版本打破了 Spring 旧版本。
如果你愿意,你们可以在这一点上查看我的项目:
https://github.com/mahonrimaia/course-microservices/tree/08e1db607729d37752bac5c68cd98c4a7dbfe20d
使用 Feign 客户端我遇到了这个错误,但请求仍然失败。主要原因是我没有指定url属性,只指定了
修正前
@FeignClient(value = "${url-value-in properties-files}", configuration = FeignConfiguration.class)
修正后
@FeignClient(name = "class-name", url = "${url-value-in properties-files}", configuration = FeignConfiguration.class)
需要在添加Eureka Client的同时添加Ribbon,否则无法获取服务。
在我的 pom.xml 中我有:
<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-netflix-ribbon</artifactId>
</dependency>
在我的服务代理中:
@FeignClient(name = "movie-api")
@RibbonClient(name = "movie-api")
public interface MovieApi {
@RequestMapping(method = RequestMethod.GET, value = "/movies/{id}")
Movie getMovie(@PathVariable("id") Long id);
}