编写Eureka Server:

    1.在POM文件中引入依赖：
        <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
                </dependency>

                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-test</artifactId>
                    <scope>test</scope>
                </dependency>

                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

    2. 配置application.yml
        spring:
          application:
            name: eureka-server

        server:
          port: 8761

        eureka:
          instance:
            prefer-ip-address: true
            status-page-url-path: /actuator/info #信息查询的url link
            health-check-url-path: /actuator/health #健康检查的url
            hostname: localhost
          client:
             # Eureka Server必须禁止向自己注册 必须将eureka.client.register-with-eureka和eureka.client.fetch-registry 设置为false
            register-with-eureka: false
            fetch-registry: false
            service-url:
              defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

    3.  在EurekaServerApplication上增加@EnableEurekaServer开启 Eureka Server功能。

    4. 启动服务后，在浏览器上访问Eureka Server主界面： http://localhost:8761/
       在界面上的Instances currently registered with Eureka 这一项上没有任何注册的实例，
       没有是正常的，因为还没有Eureka Client 客户端向注册中心Eureka Server 注册实例。