1. 扩展说明

当有多个服务提供方时,将多个服务提供方组织成一个集群,并伪装成一个提供方。

2. 扩展接口

com.alibaba.dubbo.rpc.cluster.Cluster

3. 扩展配置
<dubbo:protocol cluster="xxx" />
<dubbo:provider cluster="xxx" /> <!-- 缺省值配置,如果<dubbo:protocol>没有配置cluster时,使用此配置 -->
4. 已知扩展
  • com.alibaba.dubbo.rpc.cluster.support.FailoverCluster
  • com.alibaba.dubbo.rpc.cluster.support.FailfastCluster
  • com.alibaba.dubbo.rpc.cluster.support.FailsafeCluster
  • com.alibaba.dubbo.rpc.cluster.support.FailbackCluster
  • com.alibaba.dubbo.rpc.cluster.support.ForkingCluster
  • com.alibaba.dubbo.rpc.cluster.support.AvailableCluster
5. 扩展示例

Maven项目结构

src
 |-main
    |-java
        |-com
            |-xxx
                |-XxxCluster.java (实现Cluster接口)
    |-resources
        |-META-INF
            |-dubbo
                |-com.alibaba.dubbo.rpc.cluster.Cluster (纯文本文件,内容为:xxx=com.xxx.XxxCluster)

XxxCluster.java

package com.xxx;
 
import com.alibaba.dubbo.rpc.cluster.Cluster;
import com.alibaba.dubbo.rpc.cluster.support.AbstractClusterInvoker;
import com.alibaba.dubbo.rpc.cluster.Directory;
import com.alibaba.dubbo.rpc.cluster.LoadBalance;
import com.alibaba.dubbo.rpc.Invoker;
import com.alibaba.dubbo.rpc.Invocation;
import com.alibaba.dubbo.rpc.Result;
import com.alibaba.dubbo.rpc.RpcException;
 
public class XxxCluster implements Cluster {
    public <T> Invoker<T> merge(Directory<T> directory) throws RpcException {
        return new AbstractClusterInvoker<T>(directory) {
            public Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
                // ...
            }
        };
    }
}

META-INF/dubbo/com.alibaba.dubbo.rpc.cluster.Cluster

xxx=com.xxx.XxxCluster