spring cloud erueka:主要负责完成微服务框架中服务治理功能。
本章的主要功能有:
- 构建服务注册中心;
- 服务注册和服务发现;
- Eureka的基础框架;
- eureka的服务治理机制;
- eureka的配置;
服务治理:
服务治理是微服务最为核心和基础的模块,用来实现微服务的自动注册和发现;
- 服务注册:
- 服务发现:
spring cloud eureka,使用netfilix eureka来实现服务注册和发现。他既包含了服务端组件,也包含了客户端组件。
eureka服务端:服务注册中心;
eureka客户端:处理服务的注册和发现。
搭建服务注册中心:
依赖包:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.4.RELEASE</version>
<relativePath />
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.SR1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
启动:
@EnableEurekaServer
@SpringBootApplication
public class FishEurekaApplication {
public static void main(String[] args) {
new SpringApplicationBuilder(FishEurekaApplication.class).web(true).run(args);
}
}
配置:
spring.application.name=eureka-server
server.port=1111
eureka.instance.hostname=localhost
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
eureka.client.serviceUrl.defaultZone=http://${eureka.instance.hostname}:${server.port}/eureka/
logging.file=${spring.application.name}.log
注册服务提供者:
依赖:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.4.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<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>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.SR1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
配置:
spring.application.name=eureka-client
server.port=2001
eureka.client.serviceUrl.defaultZone=http://localhost:1111/eureka/
代码:
@EnableDiscoveryClient
@SpringBootApplication
public class FishClientApplication {
public static void main(String[] args) {
new SpringApplicationBuilder(FishClientApplication.class).web(true).run(args);
}
}
高可用注册中心:
eureka服务治理中,所有的节点及时服务提供方,也是服务消费方。eureka高可用注册中心,其实就是将自己作为服务向其他服务注册自己。形成一组互相注册的服务注册中心。
服务发现与消费:
服务消费者主要有两个目标:发现服务和消费服务;
服务的发现由eureka客户端提供,服务消费由由ribbon实现。
ribbon:ribbon基于http和TCP的客户端负载均衡器,它通过客户端配置的ribbonserverlist服务端列表轮询访问达到负载均衡的目的。ribbon和eureka整合使用,重写轮询机制。
依赖:
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>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
</dependencies>
代码:
@EnableDiscoveryClient
@SpringBootApplication
public class FishRibbonApplication {
@LoadBalanced
@Bean
RestTemplate restTemplate() {
return new RestTemplate();
}
public static void main(String[] args) {
SpringApplication.run(FishRibbonApplication.class, args);
}
}
@RestController
public class ConsumerController {
@Autowired
private RestTemplate restTemplate;
@RequestMapping("/ribbon-consumer")
public String helloConsumer() {
return restTemplate.getForEntity("http://HELLO-SERVICE/hello", String.class).getBody();
}
}
spring.application.name=ribbon-consumer
server.port=9000
eureka.client.serviceUrl.defaultZone=http://localhost:1111/eureka/