Ribbon 负载均衡

什么是Ribbon?

Ribbon 是Netflix 公司开源的一个负载均衡的组件将负载均衡逻辑封装在客户端中并且运行在客户端的进程里

Ribbon 作为服务消费者的负载均衡器有两种使用方式一种是和RestTemplate 相结合另一种是和Feign 相结合 Feign 已经默认集成了Ribbon

什么是负载均衡?

负载均衡是指将负载分摊到多个执行单元上

假如有2000个用户访问服务如果没有负载均衡可能全部的服务都访问8001 而8002则没事干负载均衡的作用就是将负载分摊到多个执行单元上

打开工程如果没有该工程点击 https://www.cnblogs.com/chenziyue/p/12482345.html

修改配置文件

server:
  port: ${PORT:8006}
eureka:
  instance:
    hostname: eureka-client
  client:
    serviceUrl: 
      defaultZone: http://eureka01:8001/eureka/
spring:
  application:
    name: eureka-client

添加代码

@RestController
public class HiController {
    @Value("${server.port}")
    private String port;
    @Autowired
    DiscoveryClient discoveryClient;
    @RequestMapping("/hi/{name}")
    public String home(@PathVariable String name){
        return "hi" + name + "i am port:" + port ;
    }
}

创建新工程(继承父工程)

导入依赖

<dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-eureka-server</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-ribbon</artifactId>
    </dependency>
  </dependencies>

配置文件

server:
  port: 8004
eureka:
  instance:
    hostname: ribbon-client
  client:
    service-url: 
      defaultZone:
        http://eureka01:8001/eureka/
spring:
  application:
    name: ribbon-client

启动类

@SpringBootApplication
@EnableDiscoveryClient
public class RibbonApp 
{
    @Bean
    // 加载负载均衡
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }

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