LoadBalance负载均衡

转载自：https://blog.youkuaiyun.com/qq924862077/article/details/79676932

  
  Dubbo提供了负载均衡，接口如下：

//默认负载均衡算法是random
@SPI(RandomLoadBalance.NAME)
public interface LoadBalance {
 
    /**
     * select one invoker in list.
     *
     * @param invokers   invokers.
     * @param url        refer url
     * @param invocation invocation.
     * @return selected invoker.
     */
	  //根据负载均衡算法获取将要调用的Invoker
    @Adaptive("loadbalance")
    <T> Invoker<T> select(List<Invoker<T>> invokers, URL url, Invocation invocation) throws RpcException;

}

  Dubbo提供的负载均衡器有如下：

• org.apache.dubbo.rpc.cluster.loadbalance.RandomLoadBalance
• org.apache.dubbo.rpc.cluster.loadbalance.RoundRobinLoadBalance
• org.apache.dubbo.rpc.cluster.loadbalance.ConsistentHashLoadBalance
• org.apache.dubbo.rpc.cluster.loadbalance.LeastActiveLoadBalance
• …

  配置使用
  服务端服务级别：<dubbo:service interface="..." loadbalance="roundrobin" />
  客户端服务级别：<dubbo:reference interface="..." loadbalance="roundrobin" />
  服务端方法级别：

<dubbo:service interface="...">
    <dubbo:method name="..." loadbalance="roundrobin"/>
</dubbo:service>

  客户端方法级别：

<dubbo:reference interface="...">
    <dubbo:method name="..." loadbalance="roundrobin"/>
</dubbo:reference>