注册中心在微服务中是必不可少的一部分，主要用来实现服务自治的功能，本文则主要记载使用Netflix提供的Eureka作为注册中心，来实现服务自治的功能。
实际上Eureka的集群搭建方法很简单：每一台Eureka只需要在配置中指定另外多个Eureke的地址，就可以实现一个集群的搭建了
例如：
两节点
-- 节点1注册到节点2
--节点2注册到节点1
三节点
--节点1注册到节点2,3
--节点2注册到节点1,3
--节点3注册到节点1,2
我做的是两个Eureka节点构建注册中心，然后一个producer和一个customer分别进行提供服务和请求服务：见图
节点1：
先新建一个Maven项目，添加依赖(基于jdk11,如果不是jdk11,可以不添加)
pom.xml主要代码
1 <parent> 2 <groupId>org.springframework.boot</groupId> 3 <artifactId>spring-boot-starter-parent</artifactId> 4 <version>1.5.4.RELEASE</version> 5 <relativePath/> 6 </parent> 7 8 <properties> 9 <java.version>11</java.version> 10 </properties> 11 12 <!-- 依赖 --> 13 <dependencies> 14 <!-- Eureka --> 15 <dependency> 16 <groupId>org.springframework.cloud</groupId> 17 <artifactId>spring-cloud-starter-eureka-server</artifactId> 18 </dependency> 19 20 <!--java 11 缺少的模块 javax.xml.bind--> 21 <dependency> 22 <groupId>javax.xml.bind</groupId> 23 <artifactId>jaxb-api</artifactId> 24 <version>2.3.0</version> 25 </dependency> 26 <dependency> 27 <groupId>com.sun.xml.bind</groupId> 28 <artifactId>jaxb-impl</artifactId> 29 <version>2.3.0</version> 30 </dependency> 31 <dependency> 32 <groupId>org.glassfish.jaxb</groupId> 33 <artifactId>jaxb-runtime</artifactId> 34 <version>2.3.0</version> 35 </dependency> 36 <dependency> 37 <groupId>javax.activation</groupId> 38 <artifactId>activation</artifactId> 39 <version>1.1.1</version> 40 </dependency> 41 42 <!-- 添加 Spring-Security 不需要则不添加--> 43 <dependency> 44 <groupId>org.springframework.boot</groupId> 45 <artifactId>spring-boot-starter-security</artifactId> 46 </dependency> 47 </dependencies> 48 49 <!-- Spring Cloud --> 50 <dependencyManagement> 51 <dependencies> 52 <dependency> 53 <groupId>org.springframework.cloud</groupId> 54 <artifactId>spring-cloud-dependencies</artifactId> 55 <version>Dalston.SR4</version> 56 <type>pom</type> 57 <scope>import</scope> 58 </dependency> 59 </dependencies> 60 </dependencyManagement>
application.yml
--- server: ###启动端口 port: 8761 spring: ###启动的配置文件名 profiles: eureka1 ###应用名 application: name: master eureka: instance: hostname: eureka1 client: ###不向注册中心注册自己 register-with-eureka: false ###不需要检索服务 fetch-registry: false serviceUrl: defaultZone: http://127.0.0.1:8762/eureka/ server: ###关闭自我保护模式 enable-self-preservation: false ###清理的间隔为5s eviction-interval-timer-in-ms: 5000 security: basic: ###暂时关闭安全认证 enabled: false --- server: ###启动端口 port: 8762 spring: ###启动的配置文件名 profiles: eureka2 application: ###应用名 name: slaveone eureka: instance: hostname: eureka2 client: ###不向注册中心注册自己 register-with-eureka: false ###不需要检索服务 fetch-registry: false serviceUrl: defaultZone: http://127.0.0.1:8761/eureka/ server: ###关闭自我保护模式 enable-self-preservation: false ###清理的间隔为5s eviction-interval-timer-in-ms: 5000 security: basic: ###暂时关闭安全认证 enabled: false
启动类：EurekaServerApplication.class
1 @EnableEurekaServer 2 @SpringBootApplication 3 public class EurekaServerApplication { 4 5 public static void main(String [] args){ 6 SpringApplication.run(EurekaServerApplication.class, args); 7 } 8 }
启动参数 IDEA设置 --spring.profiles.active=eureka1
点击这个：
同理另外一个节点的启动类，application.yml和pom.xml文件与节点1相同
启动参数改为--spring.profiles.active=eureka2
此时，浏览器输入 http://127.0.0.1:8761/发现如下：
至此注册中心已经搭建完成
producer服务注册：
主要的pom.xml文件
1 <properties> 2 <java.version>11</java.version> 3 </properties> 4 5 <parent> 6 <groupId>org.springframework.boot</groupId> 7 <artifactId>spring-boot-starter-parent</artifactId> 8 <version>1.5.4.RELEASE</version> 9 <relativePath/> 10 </parent> 11 12 <!-- 依赖 --> 13 <dependencies> 14 <!-- Eureka --> 15 <dependency> 16 <groupId>org.springframework.cloud</groupId> 17 <artifactId>spring-cloud-starter-eureka</artifactId> 18 </dependency> 19 <!--java 11 缺少的模块 javax.xml.bind--> 20 <dependency> 21 <groupId>javax.xml.bind</groupId> 22 <artifactId>jaxb-api</artifactId> 23 <version>2.3.0</version> 24 </dependency> 25 <dependency> 26 <groupId>com.sun.xml.bind</groupId> 27 <artifactId>jaxb-impl</artifactId> 28 <version>2.3.0</version> 29 </dependency> 30 <dependency> 31 <groupId>org.glassfish.jaxb</groupId> 32 <artifactId>jaxb-runtime</artifactId> 33 <version>2.3.0</version> 34 </dependency> 35 <dependency> 36 <groupId>javax.activation</groupId> 37 <artifactId>activation</artifactId> 38 <version>1.1.1</version> 39 </dependency> 40 41 <!-- Actuator 健康检查 --> 42 <dependency> 43 <groupId>org.springframework.boot</groupId> 44 <artifactId>spring-boot-starter-actuator</artifactId> 45 </dependency> 46 </dependencies> 47 48 <!-- Spring Cloud --> 49 <dependencyManagement> 50 <dependencies> 51 <dependency> 52 <groupId>org.springframework.cloud</groupId> 53 <artifactId>spring-cloud-dependencies</artifactId> 54 <version>Dalston.SR4</version> 55 <type>pom</type> 56 <scope>import</scope> 57 </dependency> 58 </dependencies> 59 </dependencyManagement>
application.properties文件：
spring.application.name=producer server.port=8081 eureka.client.service-url.defaultZone=http://127.0.0.1:8761/eureka/,http://127.0.0.1:8762/eureka/ ### 配置健康检查的信息 eureka.client.healthcheck.enabled=true ### 默认30s eureka.instance.lease-renewal-interval-in-seconds=5 ### 默认90秒 eureka.instance.lease-expiration-duration-in-seconds=5
1 @RestController 2 @RequestMapping("/home") 3 public class HomeController { 4 5 @GetMapping("/hello") 6 public String hello(){ 7 return "hello"; 8 } 9 }
基本的control类和启动类
1 @SpringBootApplication 2 @EnableDiscoveryClient 3 public class ProduceServiceApplication { 4 public static void main(String[] args){ 5 SpringApplication.run(ProduceServiceApplication.class, args); 6 } 7 }
启动之后再看Eureka注册中心：两个节点应该都有
访问 http:127.0.0.1:8081/home/hello 发现正常返回字符串
此时
搭建customer请求服务
pom.xml 和application.properties文件
<properties> <java.version>11</java.version> </properties> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.4.RELEASE</version> <relativePath/> </parent> <!-- 依赖 --> <dependencies> <!-- Eureka --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> </dependency> <!--java 11 缺少的模块 javax.xml.bind--> <dependency> <groupId>javax.xml.bind</groupId> <artifactId>jaxb-api</artifactId> <version>2.3.0</version> </dependency> <dependency> <groupId>com.sun.xml.bind</groupId> <artifactId>jaxb-impl</artifactId> <version>2.3.0</version> </dependency> <dependency> <groupId>org.glassfish.jaxb</groupId> <artifactId>jaxb-runtime</artifactId> <version>2.3.0</version> </dependency> <dependency> <groupId>javax.activation</groupId> <artifactId>activation</artifactId> <version>1.1.1</version> </dependency> <!-- Actuator 健康检查 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> </dependencies> <!-- Spring Cloud --> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Dalston.SR4</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement>
spring.application.name=customer server.port=8082 eureka.client.service-url.defaultZone=http://127.0.0.1:8761/eureka/,http://127.0.0.1:8762/eureka/ ### 配置健康检查的信息 eureka.client.healthcheck.enabled=true ### 默认30s eureka.instance.lease-renewal-interval-in-seconds=5 ### 默认90秒 eureka.instance.lease-expiration-duration-in-seconds=5
获取RestTemplate的类：
1 @Configuration 2 public class BeanConfiguration { 3 4 @Bean 5 @LoadBalanced 6 public RestTemplate getRestTemplate(){ 7 return new RestTemplate(); 8 } 9 }
control类
1 @RestController 2 @RequestMapping("/customer/") 3 public class CustomerServiceController { 4 5 @Autowired 6 private RestTemplate restTemplate; 7 8 @GetMapping("/callHello") 9 public String callHello(){ 10 return restTemplate.getForObject("http://producer/home/hello", String.class); 11 } 12 }
启动类：
1 @SpringBootApplication 2 @EnableDiscoveryClient 3 public class CustomerMainApplication { 4 public static void main(String[] args){ 5 SpringApplication.run(CustomerMainApplication.class, args); 6 } 7 }
首先，正常情况下访问 http://localhost:8082/customer/callHello
然后停掉节点1，继续访问看是否成功：
请求正常
重新启动节点1，查看节点2的日志：
节点2在丢失节点1之后会不断重试
直到找到节点1，高可用重新生成
如果有什么错误或者纰漏，恳请指正，谢谢