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Spring Cloud之Eureka配合Feign

  1. 注册中心Eureka Server
    1. 依赖
  2. 服务提供方
    1. 依赖
  3. 服务消费方
  4. 常见问题
    1. 1. UnknownHostException: service-provider

注册中心Eureka Server

依赖

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implementation "org.springframework.cloud:spring-cloud-starter-netflix-eureka-client:3.0.1"

增加Eureka注解

Application.java
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@SpringBootApplication
@EnableEurekaServer // 重要
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}
application.yml
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server:
  port: 2000 #自定义
eureke:
  client:
    register-with-eureka:false

服务提供方

依赖

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implementation "org.springframework.cloud:spring-cloud-starter-netflix-eureka-client:3.0.1"
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server:
  port: 8080
spring:
  application:
    name: {service-provider}
eureka:
  client:
    service-url:
      defaultZone: http://localhost:2000/eureka/
  instance:
    prefer-ip-address: true

服务消费方

FeignClient

Api.java
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@FeignClient(
        name = "{service-provider}"
)
public interface Api {

}
Application.java
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@SpringBootApplication
@EnableFeignClients // 激活feign client
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}
application.yml
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server:
  port: 8081
spring:
  application:
    name: {service-consumer}
eureka:
  client:
    service-url:
      defaultZone: http://127.0.0.1:2000/eureka/
  instance:
    prefer-ip-address: true

常见问题

1. UnknownHostException: service-provider

  1. @FeignClient里使用了url参数，比如如果写url=http://{service-provider}/，是解析不到的
  2. 可能存在自定义Feign.Client，Spring Cloud里使用FeignBlockingLoadBalancerClient作为feign client，如果自定义的Feign.Client没有和服务发现联动，则会报错
  技术 / Java
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