本章节将介绍怎样快速搭建一个 Eureka server 实例。首先启动 Eureka server 项目，然后启动 Eureka client 项目，Eureka client 项目将自动向 Eureka server 注册服务信息。我们先看看怎样创建和配置 Eureka server 实例。
Eureka server 是作为服务的注册与发现中心。它提供服务注册、提供注册表和同步状态，下面将介绍怎样利用 IDEA 搭建 Eureka server。详细步骤如下：
（1）打开“New Module”窗口，选择“Spring Initializr”向导创建项目，JDK 选择 1.8。如下图：
（2）如实填写 Maven 项目的 Group、Artifact、Type、Java Version、Version等信息，然后点击“Next”按钮进入下一步，如下图：
（3）选择我们需要引入的模块，该项目引入了“Spring Boot DevTools”、“Cloud Bootstrap”和“Eureka Server”模块依赖，然后点击“Next”按钮。如下图：
（4）填写模块名称和指定模块存放位置，最后点击“Finish”按钮完成项目创建。如下图：
（1）在 application.properties 文件中添加如下配置信息：
# 服务端口 server.port=8077 # 服务名称 spring.application.name=eureka-server # 服务地址 eureka.instance.hostname=localhost # 不向注册中心注册自己 eureka.client.register-with-eureka=false # 取消检索服务 eureka.client.fetch-registry=false # 开启注册中心的保护机制，默认是开启 eureka.server.enable-self-preservation=true # 设置保护机制的阈值，默认是0.85。 eureka.server.renewal-percent-threshold=0.5
（2）在 Eureka server 项目的启动类上面添加 @EnableEurekaServer 注解，代码如下：
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer
public class EurekaDemo1ServerApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaDemo1ServerApplication.class, args);
}
}注意：在项目启动类上使用 @EnableEurekaServer，可以将项目作为 Spring Cloud 中的注册中心，即 Eureka server 服务端。
上面两个步骤已将项目配置完成，我们可以直接运行 EurekaDemo1ServerApplication 类来启动 Eureka server 项目，启动日志如下：
. ____ _ __ _ _ /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v2.4.2) 2021-02-04 22:29:23.776 INFO 3332 --- [ restartedMain] c.h.s.e.EurekaDemo1ServerApplication : Starting EurekaDemo1ServerApplication using Java 1.8.0_45 on MS-OYCYMLXUSLLD with PID 3332 (D:\learn\Spring\springcloud\springcloud_workspaces\springcloud_netflix_eureka\eureka_demo1\eureka_demo1_server\target\classes started by Administrator in D:\learn\Spring\springcloud\springcloud_workspaces\springcloud_netflix_eureka) 2021-02-04 22:29:23.782 INFO 3332 --- [ restartedMain] c.h.s.e.EurekaDemo1ServerApplication : No active profile set, falling back to default profiles: default 2021-02-04 22:29:23.981 INFO 3332 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable 2021-02-04 22:29:23.981 INFO 3332 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG' 2021-02-04 22:29:25.932 INFO 3332 --- [ restartedMain] o.s.cloud.context.scope.GenericScope : BeanFactory id=cb86a24d-f668-33bf-a800-da5f46944e6a 2021-02-04 22:29:26.627 INFO 3332 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8077 (http) 2021-02-04 22:29:26.642 INFO 3332 --- [ restartedMain] o.apache.catalina.core.StandardService : Starting service [Tomcat] 2021-02-04 22:29:26.643 INFO 3332 --- [ restartedMain] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.41] 2021-02-04 22:29:26.869 INFO 3332 --- [ restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext 2021-02-04 22:29:26.871 INFO 3332 --- [ restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2886 ms 2021-02-04 22:29:27.823 INFO 3332 --- [ restartedMain] c.s.j.s.i.a.WebApplicationImpl : Initiating Jersey application, version 'Jersey: 1.19.4 05/24/2017 03:20 PM' 2021-02-04 22:29:27.944 INFO 3332 --- [ restartedMain] c.n.d.provider.DiscoveryJerseyProvider : Using JSON encoding codec LegacyJacksonJson 2021-02-04 22:29:27.945 INFO 3332 --- [ restartedMain] c.n.d.provider.DiscoveryJerseyProvider : Using JSON decoding codec LegacyJacksonJson 2021-02-04 22:29:28.152 INFO 3332 --- [ restartedMain] c.n.d.provider.DiscoveryJerseyProvider : Using XML encoding codec XStreamXml 2021-02-04 22:29:28.152 INFO 3332 --- [ restartedMain] c.n.d.provider.DiscoveryJerseyProvider : Using XML decoding codec XStreamXml 2021-02-04 22:29:28.912 INFO 3332 --- [ restartedMain] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor' 2021-02-04 22:29:30.594 INFO 3332 --- [ restartedMain] o.s.b.d.a.OptionalLiveReloadServer : LiveReload server is running on port 35729 2021-02-04 22:29:31.786 INFO 3332 --- [ restartedMain] DiscoveryClientOptionalArgsConfiguration : Eureka HTTP Client uses Jersey 2021-02-04 22:29:31.886 WARN 3332 --- [ restartedMain] iguration$LoadBalancerCaffeineWarnLogger : Spring Cloud LoadBalancer is currently working with the default cache. You can switch to using Caffeine cache, by adding it to the classpath. 2021-02-04 22:29:31.907 INFO 3332 --- [ restartedMain] o.s.c.n.eureka.InstanceInfoFactory : Setting initial instance status as: STARTING 2021-02-04 22:29:31.953 INFO 3332 --- [ restartedMain] com.netflix.discovery.DiscoveryClient : Initializing Eureka in region us-east-1 2021-02-04 22:29:31.953 INFO 3332 --- [ restartedMain] com.netflix.discovery.DiscoveryClient : Client configured to neither register nor query for data. 2021-02-04 22:29:31.968 INFO 3332 --- [ restartedMain] com.netflix.discovery.DiscoveryClient : Discovery Client initialized at timestamp 1612448971965 with initial instances count: 0 2021-02-04 22:29:32.079 INFO 3332 --- [ restartedMain] c.n.eureka.DefaultEurekaServerContext : Initializing ... 2021-02-04 22:29:32.085 WARN 3332 --- [ restartedMain] c.n.eureka.cluster.PeerEurekaNodes : The replica size seems to be empty. Check the route 53 DNS Registry 2021-02-04 22:29:32.174 INFO 3332 --- [ restartedMain] c.n.e.registry.AbstractInstanceRegistry : Finished initializing remote region registries. All known remote regions: [] 2021-02-04 22:29:32.176 INFO 3332 --- [ restartedMain] c.n.eureka.DefaultEurekaServerContext : Initialized 2021-02-04 22:29:32.190 INFO 3332 --- [ restartedMain] o.s.b.a.e.web.EndpointLinksResolver : Exposing 2 endpoint(s) beneath base path '/actuator' 2021-02-04 22:29:32.233 INFO 3332 --- [ restartedMain] o.s.c.n.e.s.EurekaServiceRegistry : Registering application EUREKA-SERVER with eureka with status UP 2021-02-04 22:29:32.236 INFO 3332 --- [ Thread-37] o.s.c.n.e.server.EurekaServerBootstrap : Setting the eureka configuration.. 2021-02-04 22:29:32.258 INFO 3332 --- [ Thread-37] o.s.c.n.e.server.EurekaServerBootstrap : isAws returned false 2021-02-04 22:29:32.259 INFO 3332 --- [ Thread-37] o.s.c.n.e.server.EurekaServerBootstrap : Initialized server context 2021-02-04 22:29:32.259 INFO 3332 --- [ Thread-37] c.n.e.r.PeerAwareInstanceRegistryImpl : Got 1 instances from neighboring DS node 2021-02-04 22:29:32.259 INFO 3332 --- [ Thread-37] c.n.e.r.PeerAwareInstanceRegistryImpl : Renew threshold is: 1 2021-02-04 22:29:32.259 INFO 3332 --- [ Thread-37] c.n.e.r.PeerAwareInstanceRegistryImpl : Changing status to UP 2021-02-04 22:29:32.276 INFO 3332 --- [ Thread-37] e.s.EurekaServerInitializerConfiguration : Started Eureka Server 2021-02-04 22:29:32.280 INFO 3332 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8077 (http) with context path '' 2021-02-04 22:29:32.282 INFO 3332 --- [ restartedMain] .s.c.n.e.s.EurekaAutoServiceRegistration : Updating port to 8077 2021-02-04 22:29:33.550 INFO 3332 --- [ restartedMain] c.h.s.e.EurekaDemo1ServerApplication : Started EurekaDemo1ServerApplication in 11.87 seconds (JVM running for 16.179)
使用浏览器运行 http://localhost:8077，运行效果如下图：
到这里 Eureka server 项目创建完成，也能成功运行了。上图中“Instances currently registered with Eureka”中的表格中没有任何可用的服务实例。等我们下一个章节创建 Eureka client 实例后，该表格将会看到 Eureka client 服务。
