Spring Cloud 之 Spring Cloud Eureka（四）

一、简介Eureka 是Netflix公司开源的一个服务注册与发现组件。Spring将它集成进来形成Spring Cloud Eureka 。二、构建eureka server 注册中心创建一个Spring Boot项目添加依赖 spring-cloud-starter-eureka-server .org.springframework.cloud

冰清雪酷

266人浏览 · 2017-08-18 15:48:09

冰清雪酷 · 2017-08-18 15:48:09 发布

一、简介

Eureka 是Netflix公司开源的一个服务注册与发现组件。Spring将它集成进来形成Spring Cloud Eureka 。

二、构建eureka server 注册中心

创建一个Spring Boot项目添加依赖 spring-cloud-starter-eureka-server .

<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>

创建程序入口类，增加注解@EnableEurekaServer

@SpringBootApplication
@EnableEurekaServer
public class EurekaApplication {

   public static void main(String[] args) {
      SpringApplication.run(EurekaApplication.class, args);
   }
}

配置文件application.yml 增加eureka相关配置

spring:
  application:
    name: eureka-server
server:
  port: 8761
eureka:
  instance:
    hostname: localhost
  client:
    register-with-eureka: false
    fetch-registry: false
    service-url:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

  server:
    eviction-interval-timer-in-ms: 60000 #清理时间间隔

hostname:eureka所在服务器名（需要修改host 文件）

fetch-registry:false 不获取注册服务类别

eviction-interval-timer-in-ms 扫描间隔毫秒

启动程序：访问localhost:8761查看eureka监控页面

三、构建eureka-client-provider

创建spring boot 项目添加依赖 spring-cloud-starter-web,spring-cloud-start-eureka

<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>

创建程序入口类增加注解@EnableEurekaClient或者@EnableDiscoveryClient

@SpringBootApplication
@EnableEurekaClient
@RestController
public class EurekaClientProviderApplication {

   @RequestMapping("/hello")
   public String hello(){
      return "hello";
   }
   public static void main(String[] args) {
      SpringApplication.run(EurekaClientProviderApplication.class, args);
   }
}

配置文件appliction.yml 增加eureka 配置

server:
  port: 8000
spring:
  application:
    name: eureka-client-provider
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/  #eureka服务地址 用来服务发现
  instance:
    lease-renewal-interval-in-seconds: 3 #3秒钟一次心跳
    lease-expiration-duration-in-seconds: 5 #5秒超时

启动服务访问 localhost:8000/hello 返回hello 程序正常

四、构建eureka-client-consumer

创建spring boot 项目添加依赖 spring-cloud-starter-web,spring-cloud-start-eureka

<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>

创建程序入口类，并提供hello服务。

@SpringBootApplication
@EnableEurekaClient
@RestController
public class EurekaClientConsumerApplication {
   @Autowired
   RestTemplate restTemplate;
   @Bean
   @LoadBalanced
   RestTemplate restTemplate(){
      return new RestTemplate();
   }
   @RequestMapping("/hello")
   public String hello(){
      return  restTemplate.getForObject("http://eureka-client-provider/hello", String.class);
   }
   public static void main(String[] args) {
      SpringApplication.run(EurekaClientConsumerApplication.class, args);
   }
}

在这个类中，我们通过restTemplate来构建负载均衡，在构建是添加注解@LoadBanlance启用RestTemplate负载均衡能力。这里的访问的路径 http://eureka-client-provider/hello 使用的是eureka-client-provider而不是localhost:8000.

配置文件 application.yml

server:
  port: 8001
spring:
  application:
    name: eureka-client-consumer
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/  #eureka服务地址 用来服务发现
  instance:
    lease-renewal-interval-in-seconds: 3 #3秒钟一次心跳
    lease-expiration-duration-in-seconds: 5 #5秒超时