书第43页右下角，案例编写有误 about deep-in-spring-cloud-samples HOT 1 OPEN

@GetMapping("/hello")
public Mono hello() {
Flux instances = reactiveDiscoveryClient.getInstances(serviceName);
// 从服务实例中取第一个
ServiceInstance serviceInstance = instances.blockFirst();
// 使用WebClient调用服务实例对应的节点信息中的“/echo”方法
return WebClient.create("http://" + serviceInstance.getHost() + ":" + serviceInstance.getPort())
.get()
.uri("/echo?name=nacos")
.retrieve()
.bodyToMono(String.class);
}

from deep-in-spring-cloud-samples.