深度解析：Spring Cloud - 单机版Eureka服务治理注册中心搭建教程

一、服务治理

服务治理是分布式架构的基础设施服务，是微服务架构中核心模块，作用是微服务实例的自动化注册与发现。当微服务比较少的时候，通过静态配置就可以完成服务的调用。但当系统越来越复杂、相应的微服务应用也不断增加，静态配置就会难以维护。服务治理这时候主要实现以下功能：

服务注册

服务发现

Netflix的Eureka项目就是一个服务治理工具，开源地址：https://github.com/Netflix/eurekaEureka由两个组件组成：服务端和客户端。当一个中间层服务首次启动时，他会将自己注册到 Eureka 中，以便让客户端找到它，同时每 30 秒发送一次心跳。如果一个服务在几分钟内没有发送心跳，它将从所有 Eureka 节点上注销。

Spring Cloud Eureka，使用Netflix Eureka来实现服务注册与发现，支持通过Java实现分布式系统，或是与JVM兼容语言构建的系统。由于Eureka服务端的服务治理也提供了restful api，所以也支持非Java语言构建的微服务应用。

二、搭建服务注册中心

1. 新建一个maven项目

添加依赖：

<?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>com.xundh.test</groupId> <artifactId>eurekaserver1</artifactId> <version>1.0-SNAPSHOT</version> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.6.RELEASE</version> <relativePath/> </parent> <dependencies> <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka-server --> <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-actuator</artifactId> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Finchley.RELEASE</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></project>

通过注解启用服务注册中心

package com.xundh.test;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;@EnableEurekaServer@SpringBootApplicationpublic class EurekaServerApplication { public static void main(String[] args) { SpringApplication.run(EurekaServerApplication.class, args); }}

bootstrap.yml

spring: application: name: eureka cloud: config: uri: ${CONFIG_SERVER_URL:http://localhost:8888}

设置application.yml：

server: port: 8761 debug: trueeureka: client: registerWithEureka: false fetchRegistry: false server: waitTimeInMsWhenSyncEmpty: 0

配置说明：

Server.port:服务端口

eureka.client.register-with-eureka:该应用为注册中心，所以设置为false，不向注册中心注册自己

eureka.client.fetch-registry: 注册中心的职责就是维护服务实例，它并不需要去检索服务，所以也设置为false

运行项目，访问网址 http://localhost:8761

2. 注册服务提供者

新建一个maven项目

设置 pom.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>com.xundh.test</groupId> <artifactId>eurekaservice</artifactId> <version>1.0-SNAPSHOT</version> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.6.RELEASE</version> <relativePath/> </parent> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> <version>1.4.7.RELEASE</version> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Finchley.RELEASE</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></project>

在启动类上加上@EnableDiscoveryClient注解：

package com.xundh;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.client.discovery.EnableDiscoveryClient;@SpringBootApplication@EnableDiscoveryClientpublic class ServiceApplication { public static void main(String[] args) { SpringApplication.run(ServiceApplication.class, args); }}

建一个RestController

package com.xundh;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.cloud.client.discovery.DiscoveryClient;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class HelloController { private final Logger logger = LoggerFactory.getLogger(HelloController.class); @Autowired private DiscoveryClient client; @RequestMapping(value="/hello", method = RequestMethod.GET) public String index(){// ServiceInstance instance = client. logger.info("/hello,host"); return "Hello World"; }}

配置文件application.yml

spring: application: name: my-eureka-serviceeureka: client: serviceUrl: defaultZone: http://localhost:8761/eureka/

启动后，在注册中心可以看到注册了新的服务。