Ribbon 服务发现（Ribbon）

1. 启动【服务中心】集群，即 Eureka Server
   localhost:/8081、
   localhost:/8082、
   localhost:/8083
   其实单机版也行...
   pom、启动类、yml文件

2. 启动【服务提供者】集群 ，即Eureka Client
   localhost:/52601、
   localhost:/52602、
   localhost:/52603

3. 创建【服务消费者】，即Eureka Discovery Client（Ribbon），本质使用RestTemplate

   • pom文件:

        <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>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
        </dependency> 
     

   • 启动类:

     @SpringBootApplication
     @EnableDiscoveryClient        //启动Eureka服务发现的相关配置
     public class EurekaRibbonApplication {
     
         public static void main(String[] args) {
             SpringApplication.run(EurekaRibbonApplication.class, args);
         }
     }
     

   • RestTemplate配置&&Service层&&Controller层

     配置类 EurekaRibbonConfig :

     @Configuration
     public class EurekaRibbonConfig {
         @Bean
         @LoadBalanced   //实现负载均衡
         public RestTemplate restTemplate() {
             return new RestTemplate();
         }
     }
     

     业务层 EurekaRibbonService:

     @Service
     public class EurekaRibbonService {
     
         @Autowired
         RestTemplate restTemplate;
     
         public String getInfo() {
             System.out.println("调用服务    EUREKA-CLIENT/info");
     
             String message = restTemplate.getForObject("http://EUREKA-CLIENT/info", String.class);
     
             System.out.println("调用 EUREKA-CLIENT/info 返回信息: " + message);
             System.out.println("调用 EUREKA-CLIENT/info 成功!");
     
             return message;
         }
     }
     

     控制层 EurekaRibbonController

     @RestController
     public class EurekaRibbonController {
     
         @Autowired
         private EurekaRibbonService eurekaRibbonService;
     
         @RequestMapping("/ribbonInfo")
         public String ribbonInfo() {
             return "获取的信息:  " + eurekaRibbonService.getInfo();
         }
     }
     

   • 配置文件yml

     server:
       port: 52610
     spring:
       application:
         name: eureka-discovery-ribbon
     eureka:
       instance:
         hostname: localhost
         lease-renewal-interval-in-seconds: 5
         lease-expiration-duration-in-seconds: 10
       client:
         service-url:
           defaultZone: http://localhost:8081/eureka/,http://localhost:8082/eureka/,http://localhost:8083/eureka/
     

启动【服务消费者】工程
访问地址http://localhost:8081/、http://localhost:8082/、http://localhost:8083/
看到好东西了（【服务消费者】EUREKA-DISCOVERY-RIBBON成功注册到【服务中心】）

多刷新几次，就能看到负载均衡的效果，即轮询请求了不同的【服务提供者】

【服务消费者】结束！！！