xml<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>cn.zxuqian</groupId> <artifactId>registry</artifactId> <version>1.0-SNAPSHOT</version> <packaging>jar</packaging> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.1.RELEASE</version> <relativePath/> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-config</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Finchley.M9</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> <repositories> <repository> <id>spring-milestones</id> <name>Spring Milestones</name> <url>https://repo.spring.io/libs-milestone</url> <snapshots> <enabled>false</enabled> </snapshots> </repository> </repositories></project>这里用到了spring-cloud-starter-netflix-eureka-server这个eureka-server核心依赖，还有访问配置中心服务的客户端组件spring-cloud-starter-config。然后在src/main/resources下创建bootstrap.yml文件，添加如下配置：ymlspring: application: name: eureka-server cloud: config: uri: http://localhost:8888此文件配置了用以读取配置文件的应用名，即spring.application.name，它的名字对应于服务中心的文件名。另外Eureka的自动注册和发现也是基于这个参数的。然后配置了配置服务中心的uri。新建一个Java类，cn.zxuqian.Application，使用如下代码：Javapackage cn.zxuqian;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;@EnableEurekaServer@SpringBootApplicationpublic class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); }}这里只用@EnableEurekaServer一条注解即把该应用配置为Eureka Server。然后在配置中心的git仓库中创建eureka-server.yml文件，添加如下配置：ymlserver: port: 8761eureka: client: register-with-eureka: false fetch-registry: false此文件配置了eureka-server的端口，以及关闭eureka自我注册和发现，因为如果不关闭的话，eureka在启动过程中就会去尝试注册自己，然而发现服务并没有启动就会报错。到此，eureka server就配置完了。## 更新Web Client现在我们要更新web client，使之可以被eureka自动注册和发现。首页在pom.xml中添加eureka client的依赖：xml<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId></dependency>然后在Application类中加上@EnableDiscoveryClient注解：Java@EnableDiscoveryClient@SpringBootApplicationpublic class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); }}最后我们创建一个类用以测试服务是不是已成功注册和发现。新建一个Java类cn.zxuqian.controllers.ServiceInstanceController，添加如下代码：Javapackage cn.zxuqian.controllers;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.cloud.client.ServiceInstance;import org.springframework.cloud.client.discovery.DiscoveryClient;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import java.util.List;@RestControllerpublic class ServiceInstanceController { @Autowired private DiscoveryClient discoveryClient; @RequestMapping("/service-instances/{applicationName}") public List<ServiceInstance> serviceInstancesByApplicationName( @PathVariable String applicationName) { return this.discoveryClient.getInstances(applicationName); }}这是一个普通的RestController, 定义了一个DiscoveryClient类型的变量并添加了@Autowire注解。此注解是Spring框架提供的依赖注入功能，在Spring的context下，它会自动寻找DiscoveryClient的实现类，此处是eureka client。关于Spring的一些特性和原理，将在以后的博文中讲到。此类还定义了serviceInstancesByApplicationName方法，用以处理/service-instances/{applicationName}请求。这里的{applicationName}匹配url路径中/service-instances/以后的部分，然后用@PathVariable注解赋值给方法的applicationName参数。例如访问http://localhost:8080/service-instances/web-client，那么applicationName的值就是web-client。方法的作用是从discoveryClient中根据spring.application.name的值来取出对应的实例信息，返回的是一个list，会自动转换为json数组的形式返回给浏览器。## 测试因为eureka server和web client都需要从配置服务中读取配置，所以先启动config-server，然后再启动eureka-server，最后启动web-client，在启动成功后可能需要稍等十几秒让eureka-server发现和注册web-client。完成之后访问http://localhost:8080/service-instances/web-client，会得到如下结果：json[{"host":"xuqians-imac","port":8080,"instanceInfo":{"instanceId":"xuqians-imac:web-client","app":"WEB-CLIENT","appGroupName":null,"ipAddr":"192.168.72.31","sid":"na","homePageUrl":"http://xuqians-imac:8080/","statusPageUrl":"http://xuqians-imac:8080/actuator/info","healthCheckUrl":"http://xuqians-imac:8080/actuator/health","secureHealthCheckUrl":null,"vipAddress":"web-client","secureVipAddress":"web-client","countryId":1,"dataCenterInfo":{"@class":"com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo","name":"MyOwn"},"hostName":"xuqians-imac","status":"UP","leaseInfo":{"renewalIntervalInSecs":30,"durationInSecs":90,"registrationTimestamp":1525319124967,"lastRenewalTimestamp":1525319124967,"evictionTimestamp":0,"serviceUpTimestamp":1525319124363},"isCoordinatingDiscoveryServer":false,"metadata":{"management.port":"8080"},"lastUpdatedTimestamp":1525319124967,"lastDirtyTimestamp":1525319124297,"actionType":"ADDED","asgName":null,"overriddenStatus":"UNKNOWN"},"metadata":{"management.port":"8080"},"uri":"http://xuqians-imac:8080","serviceId":"WEB-CLIENT","secure":false,"scheme":null}]注意一下，这里并没有把配置中心服务设置为可以被eureka server注册和发现，因为这里把配置文件都放到了config-server中，它和eureka server有着鸡生蛋，蛋生鸡的问题，所以如果要让config-server被自动注册和发现，那么就需要单独配置eureka server，然后在config server中配置eureka的uri，以及设置spring.cloud.config.discovery.enabled为true。具体以后需要用的时候再详细说明。## 总结配置eureka server相当简单，只需要加一条@EnableEurekaServer注解，并在配置中关闭自我注册和发现即可。然后在客户端应用的Application类中加上@EnableDiscoveryClient注解即可。欢迎访问我的博客此内容由惯性聚合(RSS阅读器)自动聚合整理，仅供阅读参考。 原文来自 — 版权归原作者所有。