輪詢演算法的核心為：用發出請求的次數除以所呼叫微服務的提供者數量，並取餘數。

演算法如下：

介面：

package order.lb;

import org.springframework.cloud.client.ServiceInstance;

import java.util.List;

public interface LoadBalancer {
    ServiceInstance instances(List<ServiceInstance> serviceInstances);

}
實現類：

@Component
public class MyLB implements LoadBalancer{
 
   private AtomicInteger atomicInteger=new AtomicInteger(0);
   public final  int getAndIncrement(){
       int current;
       int next;
       do{
           current=this.atomicInteger.get();
           next=current>=214748364?0:current+1;
       }while (!this.atomicInteger.compareAndSet(current,next));
 
       System.out.println("next:"+next);
       return next;
   }
    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {

        int i = getAndIncrement() % serviceInstances.size();
        return serviceInstances.get(i);
    }
}
使用(需註釋@LoadBalanced註解)：

@GetMapping("consumer/payment/lb")
 
public String getPayment(){
    List<ServiceInstance> serviceInstances = discoveryClient.getInstances("CLOUD-PAYMENT-SERVICE");
    if (serviceInstances==null||serviceInstances.size()<=0){
        return  null;
    }
    ServiceInstance instances = loadBalancer.instances(serviceInstances);
    URI uri = instances.getUri();
 return    restTemplate.getForObject(uri+"/payment/lb",String.class);
}