SpringCloud 2020-Ribbon負載均衡服務調用的實現
1、概述
官網:https://github.com/Netflix/ribbon/wiki/Getting-Started
Ribbon目前也進入維護模式,未來替換方案:
LB(負載均衡)
集中式LB
進程內LB
Ribbon就是負載均衡+RestTemplate調用
2、Ribbon負載均衡演示
1、架構說明
總結:Ribbon其實就是一個軟負載均衡的客戶端組件,他可以和其他所需請求的客戶端結合使用,和eureka結合隻是其中的一個實例。
2、
3、二說RestTemplate的使用
官網
修改cloud-consumer-order80
getForObject方法/getForEntity方法
postForObject/postForEntity
- GET請求方法
- POST請求方法
4、依次2啟動7001,7002,8001,8002,80。訪問:http://localhost/consumer/payment/getForEntity/31
3、Ribbon核心組件IRule
IRule:根據特定算法從服務列表中選取一個要訪問的服務
Ribbon自帶負載均衡算法:
如何替換負載均衡算法:修改cloud-consumer-order80
1、註意配置細節
2、新建package
3、在myrule下面新建配置類MySelfRule
package com.liukai.myrule; import com.netflix.loadbalancer.IRule; import com.netflix.loadbalancer.RandomRule; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; /** * @author liukai * @version 1.0.0 * @ClassName MySelfRule.java * @Description TODO * @createTime 2021年03月21日 11:50:00 */ @Configuration public class MySelfRule { @Bean(name = "myRandomRule") public IRule myRule(){ return new RandomRule();//定義為隨機 } }
4、主啟動類添加@RibbonClient
package com.liukai.springcloud; import com.liukai.myrule.MySelfRule; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; import org.springframework.cloud.netflix.ribbon.RibbonClient; /** * @author liukai * @version 1.0.0 * @ClassName OrderMain80.java * @Description TODO * @createTime 2021年03月19日 18:27:00 */ @SpringBootApplication @EnableEurekaClient @RibbonClient(name = "CLOUD-PAYMENT-SERVICE",configuration = MySelfRule.class) public class OrderMain80 { public static void main(String[] args) { SpringApplication.run(OrderMain80.class); } }
5、測試:依次啟動7001,7002,8001,8002,cloud-consumer-order80
訪問:http://localhost/consumer/payment/get/31
多方問幾次,可以發現查詢的端口號是隨機的,而不是交替出現瞭
4、Ribbon負載均衡算法
4.1 原理 + 源碼
1、註釋掉cloud-consumer-order80主啟動類的@RibbonClient
2、原理
3、源碼:
public Server choose(ILoadBalancer lb, Object key) { if (lb == null) { log.warn("no load balancer"); return null; } Server server = null; int count = 0; while (server == null && count++ < 10) { List<Server> reachableServers = lb.getReachableServers(); List<Server> allServers = lb.getAllServers(); int upCount = reachableServers.size(); int serverCount = allServers.size(); if ((upCount == 0) || (serverCount == 0)) { log.warn("No up servers available from load balancer: " + lb); return null; } int nextServerIndex = incrementAndGetModulo(serverCount); server = allServers.get(nextServerIndex); if (server == null) { /* Transient. */ Thread.yield(); continue; } if (server.isAlive() && (server.isReadyToServe())) { return (server); } // Next. server = null; } if (count >= 10) { log.warn("No available alive servers after 10 tries from load balancer: " + lb); } return server; } /** * Inspired by the implementation of {@link AtomicInteger#incrementAndGet()}. * * @param modulo The modulo to bound the value of the counter. * @return The next value. */ private int incrementAndGetModulo(int modulo) { for (;;) { int current = nextServerCyclicCounter.get(); int next = (current + 1) % modulo; if (nextServerCyclicCounter.compareAndSet(current, next)) return next; } }
4.2 手寫負載均衡算法
1、修改8001,8002的controller
// 手寫負載均衡需要用到 @GetMapping(value = "/payment/lb") public String getPaymentLB(){ return serverPort; }
2、cloud-consumer-order80的ApplicationContextBean去掉@LoadBalanced
3、新建接口LoadBalancer
package com.liukai.springcloud.lb; import org.springframework.cloud.client.ServiceInstance; import java.util.List; /** * @author liukai * @version 1.0.0 * @ClassName LoadBalancer.java * @Description TODO * @createTime 2021年03月21日 12:24:00 */ public interface LoadBalancer { //收集服務器總共有多少臺能夠提供服務的機器,並放到list裡面 ServiceInstance instances(List<ServiceInstance> serviceInstances); }
4、新建實現類MyLB
package com.liukai.springcloud.lb; import org.springframework.cloud.client.ServiceInstance; import org.springframework.stereotype.Component; import java.util.List; import java.util.concurrent.atomic.AtomicInteger; /** * @author liukai * @version 1.0.0 * @ClassName MyLB.java * @Description TODO * @createTime 2021年03月21日 12:27:00 */ @Component public class MyLB implements LoadBalancer { private AtomicInteger atomicInteger = new AtomicInteger(0); //坐標 private final int getAndIncrement() { int current; int next; do { current = this.atomicInteger.get(); next = current >= 2147483647 ? 0 : current + 1; } while (!this.atomicInteger.compareAndSet(current, next)); //第一個參數是期望值,第二個參數是修改值是 System.out.print("*******第幾次訪問,次數next: " + next); return next; } @Override public ServiceInstance instances(List<ServiceInstance> serviceInstances) { //得到機器的列表 int index = getAndIncrement() % serviceInstances.size(); //得到服務器的下標位置 System.out.println(" ====>端口:" + serviceInstances.get(index).getPort()); return serviceInstances.get(index); } }
5、修改OrderController
@Resource private LoadBalancer loadBalancer; @Resource private DiscoveryClient discoveryClient; @GetMapping(value = "/consumer/payment/lb") public String getPaymentLB(){ List<ServiceInstance> instances = discoveryClient.getInstances("CLOUD-PAYMENT-SERVICE"); if (instances == null || instances.size() <= 0){ return null; } // instances.forEach(System.out::println); // 使用手寫的負載均衡算法獲取服務 ServiceInstance serviceInstance = loadBalancer.instances(instances); // 獲取服務的地址 URI uri = serviceInstance.getUri(); // 拼接地址訪問 return restTemplate.getForObject(uri+"/payment/lb",String.class); }
6、測試:訪問 http://localhost/consumer/payment/lb
發現訪問的端口號開始輪詢出現,手寫負載均衡輪詢算法成功
到此這篇關於SpringCloud 2020-Ribbon負載均衡服務調用的實現的文章就介紹到這瞭,更多相關SpringCloud Ribbon負載均衡內容請搜索WalkonNet以前的文章或繼續瀏覽下面的相關文章希望大傢以後多多支持WalkonNet!
推薦閱讀:
- 聊聊SpringCloud中的Ribbon進行服務調用的問題
- Java Spring Cloud 負載均衡詳解
- spring cloud 集成 ribbon負載均衡的實例代碼
- Spring cloud alibaba之Ribbon負載均衡實現方案
- 淺談SpringCloud之Ribbon詳解