Eureka是Netflix开发的服务发现框架,本身是一个基于REST的服务,主要用于定位运行在AWS域中的中间层服务,以达到负载均衡和中间层服务故障转移的目的。SpringCloud将它集成在其子项目spring-cloud-netflix中,以实现SpringCloud的服务发现功能。 Eureka包含两个组件:Eureka Server和Eureka Client。
Eureka Server提供服务注册服务,各个节点启动后,会在Eureka Server中进行注册,这样Eureka Server中的服务注册表中将会存储所有可用服务节点的信息,服务节点的信息可以在界面中直观的看到。 Eureka Server本身也是一个服务,默认情况下会自动注册到Eureka注册中心。 如果搭建单机版的Eureka Server注册中心,则需要配置取消Eureka Server的自动注册逻辑。毕竟当前服务注册到当前服务代表的注册中心中是一个说不通的逻辑。 Eureka Server通过Register、Get、Renew等接口提供服务的注册、发现和心跳检测等服务。
Eureka Client是一个java客户端,用于简化与Eureka Server的交互,客户端同时也具备一个内置的、使用轮询(round-robin)负载算法的负载均衡器。在应用启动后,将会向Eureka Server发送心跳,默认周期为30秒,如果Eureka Server在多个心跳周期内没有接收到某个节点的心跳,Eureka Server将会从服务注册表中把这个服务节点移除(默认90秒)。 Eureka Client分为两个角色,分别是:Application Service(Service Provider)和Application Client(Service Consumer)
使用IDEA新建一个maven项目spring-cloud-demo,删除src目录,在pom.xml中添加以下依赖
<?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> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.2.6.RELEASE</version> <relativePath /> <!-- lookup parent from repository --> </parent> <groupId>org.example</groupId> <artifactId>spring-cloud-demo</artifactId> <packaging>pom</packaging> <version>1.0-SNAPSHOT</version> <modules> <module>spring-cloud-eureka-server</module> <module>spring-cloud-eureka-client</module> </modules> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <maven.compiler.encoding>UTF-8</maven.compiler.encoding> <!-- jdk版本 --> <java.version>1.8</java.version> <!-- SpringCloud版本号,官方最新稳定版本 --> <spring-cloud.version>Hoxton.SR3</spring-cloud.version> </properties> <!-- 公共依赖 --> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.12</version> </dependency> </dependencies> <!--依赖管理,用于管理spring-cloud的依赖 --> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>${spring-cloud.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <build> <resources> <!-- 先指定 src/main/resources下所有文件及文件夹为资源文件 --> <resource> <directory>src/main/resources</directory> <includes> <include>**/*</include> </includes> <filtering>true</filtering> </resource> </resources> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>${maven-compiler-plugin.version}</version> <configuration> <source>${java.version}</source> <target>${java.version}</target> <encoding>${maven.compiler.encoding}</encoding> </configuration> </plugin> <plugin> <!--打包跳过测试--> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-surefire-plugin</artifactId> <version>${maven-surefire-plugin.version}</version> <configuration> <skipTests>true</skipTests> </configuration> </plugin> <!-- resources资源插件 --> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-resources-plugin</artifactId> <version>${maven-resources-plugin.version}</version> <configuration> <encoding>UTF-8</encoding> </configuration> </plugin> </plugins> <pluginManagement> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <executions> <execution> <goals> <goal>repackage</goal> <goal>build-info</goal> </goals> </execution> </executions> </plugin> <plugin> <groupId>com.spotify</groupId> <artifactId>docker-maven-plugin</artifactId> <version>${docker-maven-plugin.version}</version> </plugin> <!-- java文档插件 --> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-javadoc-plugin</artifactId> <version>3.0.0</version> </plugin> </plugins> </pluginManagement> </build> </project> 复制代码
新建maven项目spring-cloud-eureka-server,添加如下依赖pom.xml中
<?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"> <parent> <artifactId>spring-cloud-demo</artifactId> <groupId>org.example</groupId> <version>1.0-SNAPSHOT</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>spring-cloud-eureka-server</artifactId> <dependencies> <!-- eureka服务端依赖jar包 --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId> </dependency> <!-- eureka安全组件jar包 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-security</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project> 复制代码
增加Security相关配置,关闭crsf
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http.csrf().disable(); } } 复制代码
创建一个启动类EurekaServerApplication,添加@EnableEurekaServer注解
@Slf4j @SpringBootApplication(exclude = {DataSourceAutoConfiguration.class}) @EnableEurekaServer public class EurekaServerApplication { public static void main(String[] args) { log.info("=======启动服务注册中心 eureka-server 服务项目中======="); SpringApplication.run(EurekaServerApplication.class, args); log.info("=======启动服务注册中心 eureka-server 服务项目成功======="); } } 复制代码
新建application.yml属性文件,增加下面的配置
server: #项目端口号 port: 8888 tomcat: max-connections: 200 max-threads: 300 min-spare-threads: 0 uri-encoding: UTF-8 logging: pattern: console: '%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{15} - %msg%n' spring: application: name: eureka-server eureka: #eureka实例定义 instance: #eureka实例主机名称 hostname: master #表示eureka client发送心跳给server端的频率。如果在leaseExpirationDurationInSeconds后,server端没有收到client的心跳, #则将摘除该instance。 #除此之外,如果该instance实现了HealthCheckCallback,并决定让自己unavailable的话,则该instance也不会接收到流量。 lease-renewal-interval-in-seconds: 5 #客户端进行Eureka注册的配置 client: #关闭eureka的客户端行为:注册服务 registerWithEureka: false #关闭eureka的客户端行为:订阅服务 fetchRegistry: false serviceUrl: #eureka注册中心地址 defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ server: # 关闭自我保护机制,防止失效的服务也被一直访问 (Spring Cloud默认该配置是 true) enable-self-preservation: false # 每隔10s扫描服务列表,该配置可以修改检查失效服务的时间,每隔10s检查失效服务,并移除列表 (Spring Cloud默认该配置是 60s) eviction-interval-timer-in-ms: 5000 复制代码
运行启动类启动我们的注册中心服务,浏览器输入http://localhost:8888/访问
新建maven项目spring-cloud-eureka-client-provider,添加如下依赖pom.xml中
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <parent> <artifactId>spring-cloud-demo</artifactId> <groupId>com.hxmec</groupId> <version>1.0-SNAPSHOT</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>spring-cloud-eureka-client-provider</artifactId> <name>spring-cloud-eureka-client-provider</name> <description>Demo project for Spring Boot</description> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project> 复制代码
新建application.yml,增加下面的配置
server: port: 9001 spring: application: name: eureka-client-provider logging: pattern: console: '%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{15} - %msg%n' eureka: client: service-url: defaultZone: http://localhost:8888/eureka/ 复制代码
创建一个启动类EurekaClientProviderApplication,添加@EnableDiscoveryClient注解
@SpringBootApplication @EnableDiscoveryClient public class EurekaClientProviderApplication { public static void main(String[] args) { SpringApplication.run(EurekaClientProviderApplication.class, args); } } 复制代码
创建一个DemoController,提供一个接口给消费者服务查询
@RestController @RequestMapping("/demo") public class DemoController { @Value("${server.port:#{null}}") private String serverPort; @GetMapping("/hello") public String hello() { return "Hello " + serverPort; } } 复制代码
启动项目,打开http://localhost:8888/ 可以看到应用已经注册到Eureka注册中心
创建maven项目spring-cloud-eureka-client-consumer,pom依赖和服务提供者一样,创建启动类EurekaClientConsumerApplication
@SpringBootApplication @EnableDiscoveryClient public class EurekaClientConsumerApplication { public static void main(String[] args) { SpringApplication.run(EurekaClientConsumerApplication.class, args); } } 复制代码
新建application.yml 属性文件,增加下面的配置
server: port: 9002 spring: application: name: eureka-client-consumer logging: pattern: console: '%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{15} - %msg%n' eureka: client: service-url: defaultZone: http://localhost:8888/eureka/ 复制代码
使用RestTemplate来访问http服务,创建RestTemplate配置类RestTemplateConfiguration
@Configuration public class RestTemplateConfiguration { @Bean @LoadBalanced public RestTemplate restTemplate(){ return new RestTemplate(); } } 复制代码
创建DemoController
@RestController @RequestMapping("/test") @AllArgsConstructor @Slf4j public class DemoController { private final RestTemplate restTemplate; @GetMapping("/callHello") public String callHello() { //LoadBalanced注解可以实现通过注册的服务名称来调用 //String result = restTemplate.getForObject("http://localhost:9001/demo/hello", String.class); String result = restTemplate.getForObject("http://eureka-client-provider/demo/hello", String.class); log.info("调用结果:{}" , result); return result; } } 复制代码
启动项目,打开http://localhost:8888/ 可以看到应用已经注册到Eureka注册中心
请求测试接口,验证是否成功调用生产者的接口