负载均衡算法

Posted 2021-03-02 nineberg

负载均衡算法：rest接口第几次请求数 % 服务器集群总数量 = 实际调用服务器位置下标 ， 每次服务重启动后rest 接口计数从1开始

@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 >= 2147483647 ? 0 : current + 1;
        }while (!this.atomicInteger.compareAndSet(current,next));
        System.out.println("**************第 "+ next +" 次访问*******");
        //代表第几次访问
        return next;

    }


    //负载均衡算法：rest接口第几次请求数 % 服务器集群总数量 = 实际调用服务器位置下标 ， 每次服务重启动后rest 接口计数从1开始
    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstance) {

        // serviceInstance.size 获取集群总数
        int index = getAndIncrement() % serviceInstance.size();
        return serviceInstance.get(index);
    }
}

public interface LoadBalancer {


    ServiceInstance instances(List<ServiceInstance> serviceInstance);

}

    @Resource
    private LoadBalancer loadBalancer;

    @GetMapping(value = "/consumer/payment/lb")
    public String getPaymentLB()
    {
        List<ServiceInstance> instances = discoveryClient.getInstances("CLOUD-PAYMENT-SERVICE");
        if (instances == null||instances.size() <=0){
            return null;
        }

        ServiceInstance serviceInstance = loadBalancer.instances(instances);
        URI uri = serviceInstance.getUri();

        return  restTemplate.getForObject(uri+"/payment/lb",String.class);
    }