Eureka是Netflix開源的一個RESTful服務，主要用於服務的註冊發現。Eureka由兩個元件組成：Eureka伺服器和Eureka客戶端。Eureka伺服器用作服務註冊伺服器。Eureka客戶端是一個java客戶端，用來簡化與伺服器的互動、作為輪詢負載均衡器，並提供服務的故障切換支援。

• Eureka Server 提供用於Client的服務註冊與發現
• Application Service 服務提供方 將自己註冊到Server中
• Application Client 服務呼叫方 通過Server發現服務提供方,進行呼叫

Spring Cloud 中使用

Eureka Server

1.引入依賴

<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>

或者使用Idea 勾選依賴

2.在啟動類上添加註解@EnableEurekaServer

@SpringBootApplication
@EnableEurekaServer
 

public class Eurekaserver1Application {

    public static void main(String[] args) {
        SpringApplication.run(Eurekaserver1Application.class, args);
    }
}

3.application.yml

server:
  port: 8761 #服務埠 預設Eureka埠為8761
eureka:
  client:
    service-url:
      defaultZone: http://local2:8762/eureka
 

  server:
    enable-self-preservation: false #是否開啟自我保護(在開發環境關閉)
spring:
  application:
    name: es

Eureka Client

1.新增依賴

 <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

或

2.啟動類新增@EnableEurekaClient或@EnableDiscoveryClient

@SpringBootApplication
@EnableEurekaClient
public class EurekaconsumerforfeignApplication {
    public static void main(String[] args) {
        SpringApplication.run(EurekaconsumerforfeignApplication.class, args);
    }
}

這兩個註解的區別?
3.application.yml

server:
  port: 8081
eureka:
  client:
    healthcheck:
      enabled: true
    service-url:
      defaultZone: http://local1:8761/eureka,http://local2:8762/eureka
  instance:
    prefer-ip-address: true
spring:
  application:
    name: ep