Sprint-Ribbon与负载均衡

标签（空格分隔）： Java-Spring

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Ribbon是一个基于HTTP与TCP的客户端负载均衡器。

服务端列表去轮询访问以达到均衡负载的作用。当 Ribbon与 Eureka联合使用时, Ribbon 的服务实例清单 Ribbon Serverlist会被 Discoveryenabledniwsserverlist重写,扩展成从Eureka注册中心中获取服务端列表。同时它也会用 Niwsdiscoveryping来取代Ping,它将职责委托给Eureka来确定服务端是否已经启动。在本章中,我们对Ribbon不做详细的介绍,读者只需要理解它在Eureka服务发现的基础上,实现了一套对服务实例的选择策略,从而实现对服务的消费。下一章我们会对 Ribbon做详细的介绍和分析。

客户端示例：RestTemplate + Ribbon

@SpringBootApplication
@EnableDiscoveryClient
@RestController
public class RibbonClient {
    public static void main(String[] args) {
        SpringApplication.run(RibbonClient.class, args);
    }

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

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/ribbonInvoke")
    private String ribbonInvoke() {
        RibbonMessage msg = restTemplate.getForObject("http://TG-RIBBON-SERVICE/ribbonAccept", RibbonMessage.class);
        System.out.println(msg);

        return msg.toString();
    }

}

调用后输出日志示例：

2019-02-01 16:15:53.953  INFO 11404 --- [nio-8201-exec-1] c.n.l.DynamicServerListLoadBalancer      : DynamicServerListLoadBalancer for client TG-RIBBON-SERVICE initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=TG-RIBBON-SERVICE,current list of Servers=[192.168.14.196:8056],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone; Instance count:1;   Active connections count: 0;    Circuit breaker tripped count: 0;   Active connections per server: 0.0;]
},Server stats: [[Server:192.168.14.196:8056;   Zone:defaultZone;   Total Requests:0;   Successive connection failure:0;    Total blackout seconds:0;   Last connection made:Thu Jan 01 08:00:00 CST 1970;  First connection made: Thu Jan 01 08:00:00 CST 1970;    Active Connections:0;   total failure count in last (1000) msecs:0; average resp time:0.0;  90 percentile resp time:0.0;    95 percentile resp time:0.0;    min resp time:0.0;  max resp time:0.0;  stddev resp time:0.0]
]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@53c23742