使用
服务端
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
server:
port: 9000
servlet:
context-path: /eureka-server
eureka:
instance:
hostname: localhost # eureka 实例名称
client:
register-with-eureka: false # 不向注册中心注册自己
fetch-registry: false # 是否检索服务
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaServerApplication.class);
}
}
http://localhost:9000/eureka-server/
客户端
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
server:
port: 8092
servlet:
context-path: /demo-eureka-client
eureka:
instance:
instance-id: demo-eureka-client2
prefer-ip-address: true # 访问路径可以显示 IP
client:
service-url:
defaultZone: http://localhost:9000/eureka-server/eureka # 注册中心访问地址
spring:
application:
name: demo-eureka-client
可以通过修改端口号和实例ID(instance-id)的值，使一个应用在本地运行多个实例
@SpringBootApplication
public class EurekaClientApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaClientApplication.class, args);
}
}
原理分析
客户端
客户端通过AbstractJerseyEurekaHttpClient及子类JerseyReplicationClient来向注册中心发送请求，如注册实例，更新状态等
http://localhost:9000/eureka-server/eureka/apps/ GET # 用来查询所有服务
服务端
使用Jersey来实现REST服务接口，如ApplicationsResource。EurekaServerAutoConfiguration中的jerseyFilterRegistration()方法定义了一个过滤器ServletContainer，类似SpringMVC的DispatcherServlet，做请求的分发，jerseyApplication()方法创建DefaultResourceConfig对象，使用Spring的类扫描来代替Jersey的扫描。