根据IP动态路由调用Dubbo服务【黑马java培训】

public class MyCluster implements Cluster{
   @Override
   public <T> Invoker<T> join(Directory<T> directory) throws RpcException {
       return new MyClusterInvoker(directory);
   }
}

public class MyClusterInvoker<T> extends MyAbstractClusterInvoker<T> {



 public MyClusterInvoker(Directory<T> directory) {

     super(directory);

 }

@Override
 protected Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance)
         throws RpcException {
     //1.查看是否设置了指定ip
     String ip = (String) RpcContext.getContext().get("ip");
     if (StringUtils.isBlank(ip)) {
         throw new RuntimeException("ip is blank ");
     }
     //2.检查是否有可用invoker
     checkInvokers(invokers,invocation);
     //3.根据指定ip获取对应invoker
     Invoker<T> invoked = invokers.stream().filter(invoker -> invoker.getUrl().getHost().equals(ip))
             .findFirst().orElse(null);
     //4.检查是否有可用invoker

     if(null == invoked) {

         throw new RpcException(RpcException.NO_INVOKER_AVAILABLE_AFTER_FILTER,

                 "Failed to invoke the method " + invocation.getMethodName() + " in the service "

                         + getInterface().getName() + ". No provider available for the service "

                         + directory.getUrl().getServiceKey() + " from ip " + ip + " on the consumer "

                         + NetUtils.getLocalHost() + " using the dubbo version " + Version.getVersion()

                         + ". Please check if the providers have been started and registered.");

    }

     //5.发起远程调用，失败则抛出异常

     try {
         return invoked.invoke(invocation);

     } catch (Throwable e) {

         if (e instanceof RpcException && ((RpcException) e).isBiz()) { // biz exception.

             throw (RpcException) e;

         }

         throw new RpcException(e instanceof RpcException ? ((RpcException) e).getCode() : 0,
                 "Fail invoke providers " + (invoked != null?invoked.getUrl():"")+ " " + loadbalance.getClass().getSimpleName()
                         + " select from all providers " + invokers + " for service " + getInterface().getName()
                         + " method " + invocation.getMethodName() + " on consumer " + NetUtils.getLocalHost()
                         + " use dubbo version " + Version.getVersion()
                         + ", but no luck to perform the invocation. Last error is: " + e.getMessage(),
                 e.getCause() != null ? e.getCause() : e);
     }
 }
}

public Result invoke(final Invocation invocation) throws RpcException {
  checkWhetherDestroyed();
  // binding attachments into invocation.
  Map<String, String> contextAttachments = RpcContext.getContext().getAttachments();
  if (contextAttachments != null && contextAttachments.size() != 0) {
      ((RpcInvocation) invocation).addAttachments(contextAttachments);
  }
  List<Invoker<T>> invokers = list(invocation);
    LoadBalance loadbalance = null;//initLoadBalance(invokers, invocation);
  RpcUtils.attachInvocationIdIfAsync(getUrl(), invocation);
  return doInvoke(invocation, invokers, loadbalance);
}