spring:
  cloud:
    loadbalancer:
      enabled: false

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            spring-cloud-starter-loadbalancer
        </dependency>

package cn.itxs.ecom.order.config;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
public class RestTemplateConfig {
    @LoadBalanced
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate() ;
    }
}

package cn.itxs.ecom.order.controller;

import cn.itxs.ecom.commons.service.OrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

/**
 * @Name OrderController
 * @Description 
 * @Author itxs
 * @Date 2022/4/10 20:15
 * @Version 1.0
 * @History 
 */
@RestController
public class OrderController {

    @Autowired
    OrderService orderService;

    @Autowired
    private RestTemplate restTemplate;

    @RequestMapping("/create/{userId}/{commodityCode}/{count}")
    public String create(@PathVariable("userId") String userId,@PathVariable("commodityCode") String commodityCode, @PathVariable("count") int count){
        return orderService.create(userId,commodityCode,count).toString();
    }

    @RequestMapping("/deductRest/{commodityCode}/{count}")
    public String deductRest(@PathVariable("commodityCode") String commodityCode, @PathVariable("count") int count){
        String url = "http://ecom-storage-service/deduct/"+commodityCode+"/"+count;
        return restTemplate.getForObject(url, String.class);
    }
}

server:
  port: 4080

package cn.itxs.ecom.order.config;

import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.loadbalancer.core.RandomLoadBalancer;
import org.springframework.cloud.loadbalancer.core.ReactorLoadBalancer;
import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;
import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.core.env.Environment;

public class CustomLoadBalancerConfiguration {

    @Bean
    ReactorLoadBalancer<ServiceInstance> randomLoadBalancer(Environment environment,
                                                            LoadBalancerClientFactory loadBalancerClientFactory) {
        String name = environment.getProperty(LoadBalancerClientFactory.PROPERTY_NAME);
        return new RandomLoadBalancer(loadBalancerClientFactory
                .getLazyProvider(name, ServiceInstanceListSupplier.class),
                name);
    }
}

package cn.itxs.ecom.order.config;

import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
@LoadBalancerClient(value = "ecom-storage-service", configuration = CustomLoadBalancerConfiguration.class)
public class RestTemplateConfig {

    @LoadBalanced
    @Bean
    public RestTemplate restTemplate(RestTemplateBuilder builder) {
        return builder.build() ;
    }
}

        <dependency>
            <groupId>org.springframework.boot</groupId>
            spring-boot-starter-webflux
        </dependency>

package cn.itxs.ecom.order.config;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.reactive.function.client.WebClient;

@Configuration
public class WebClientConfig {
    @LoadBalanced
    @Bean
    WebClient.Builder webClientBuilder() {
        return WebClient.builder();
    }

    @Bean
    WebClient webClient() {
        return webClientBuilder().build();
    }
}

    @Autowired
    private WebClient webClient;   

	@RequestMapping(value = "/deductWebClient/{commodityCode}/{count}")
    public Mono<String> deductWebClient(@PathVariable("commodityCode") String commodityCode, @PathVariable("count") int count) {
        String url = "http://ecom-storage-service/deduct/"+commodityCode+"/"+count;
        // WebClient
        Mono<String> result = webClient.get().uri(url)
                .retrieve().bodyToMono(String.class);
        return result;
    }

    @Autowired
    private ReactorLoadBalancerExchangeFilterFunction lbFunction;   

    @RequestMapping(value = "/deductWebFluxReactor/{commodityCode}/{count}")
    public Mono<String> deductWebFluxReactor(@PathVariable("commodityCode") String commodityCode, @PathVariable("count") int count) {
        String url = "/deduct/"+commodityCode+"/"+count;
        Mono<String> result = WebClient.builder().baseUrl("http://ecom-storage-service")
                .filter(lbFunction)
                .build()
                .get()
                .uri(url)
                .retrieve()
                .bodyToMono(String.class);
        return result;
    }

	// ʵڳInterceptingHttpAccessor
	// RestTemplate.InterceptingHttpAccessor#setInterceptors
	public void setInterceptors(List<ClientHttpRequestInterceptor> interceptors) {
		Assert.noNullElements(interceptors, "'interceptors' must not contain null elements");
		// Take getInterceptors() List as-is when passed in here
		if (this.interceptors != interceptors) {
			this.interceptors.clear();
			this.interceptors.addAll(interceptors);
			AnnotationAwareOrderComparator.sort(this.interceptors);
		}
	}

@SuppressWarnings({ "unchecked", "rawtypes" })
public class BlockingLoadBalancerClient implements LoadBalancerClient {

	private final ReactiveLoadBalancer.Factory<ServiceInstance> loadBalancerClientFactory;

	/**
	 * @deprecated in favour of
	 * {@link BlockingLoadBalancerClient#BlockingLoadBalancerClient(ReactiveLoadBalancer.Factory)}
	 */
	@Deprecated
	public BlockingLoadBalancerClient(LoadBalancerClientFactory loadBalancerClientFactory,
			LoadBalancerProperties properties) {
		this.loadBalancerClientFactory = loadBalancerClientFactory;
	}

	public BlockingLoadBalancerClient(ReactiveLoadBalancer.Factory<ServiceInstance> loadBalancerClientFactory) {
		this.loadBalancerClientFactory = loadBalancerClientFactory;
	}

	@Override
	public <T> T execute(String serviceId, LoadBalancerRequest<T> request) throws IOException {
		String hint = getHint(serviceId);
		LoadBalancerRequestAdapter<T, DefaultRequestContext> lbRequest = new LoadBalancerRequestAdapter<>(request,
				new DefaultRequestContext(request, hint));
		Set<LoadBalancerLifecycle> supportedLifecycleProcessors = getSupportedLifecycleProcessors(serviceId);
		supportedLifecycleProcessors.forEach(lifecycle -> lifecycle.onStart(lbRequest));
		ServiceInstance serviceInstance = choose(serviceId, lbRequest);
        // ѡ
		if (serviceInstance == null) {
			supportedLifecycleProcessors.forEach(lifecycle -> lifecycle.onComplete(
					new CompletionContext<>(CompletionContext.Status.DISCARD, lbRequest, new EmptyResponse())));
			throw new IllegalStateException("No instances available for " + serviceId);
		}
		return execute(serviceId, serviceInstance, lbRequest);
	}

	@Override
	public <T> T execute(String serviceId, ServiceInstance serviceInstance, LoadBalancerRequest<T> request)
			throws IOException {
		DefaultResponse defaultResponse = new DefaultResponse(serviceInstance);
		Set<LoadBalancerLifecycle> supportedLifecycleProcessors = getSupportedLifecycleProcessors(serviceId);
		Request lbRequest = request instanceof Request ? (Request) request : new DefaultRequest<>();
		supportedLifecycleProcessors
				.forEach(lifecycle -> lifecycle.onStartRequest(lbRequest, new DefaultResponse(serviceInstance)));
		try {
			T response = request.apply(serviceInstance);
			Object clientResponse = getClientResponse(response);
			supportedLifecycleProcessors
					.forEach(lifecycle -> lifecycle.onComplete(new CompletionContext<>(CompletionContext.Status.SUCCESS,
							lbRequest, defaultResponse, clientResponse)));
			return response;
		}
		catch (IOException iOException) {
			supportedLifecycleProcessors.forEach(lifecycle -> lifecycle.onComplete(
					new CompletionContext<>(CompletionContext.Status.FAILED, iOException, lbRequest, defaultResponse)));
			throw iOException;
		}
		catch (Exception exception) {
			supportedLifecycleProcessors.forEach(lifecycle -> lifecycle.onComplete(
					new CompletionContext<>(CompletionContext.Status.FAILED, exception, lbRequest, defaultResponse)));
			ReflectionUtils.rethrowRuntimeException(exception);
		}
		return null;
	}

	private <T> Object getClientResponse(T response) {
		ClientHttpResponse clientHttpResponse = null;
		if (response instanceof ClientHttpResponse) {
			clientHttpResponse = (ClientHttpResponse) response;
		}
		if (clientHttpResponse != null) {
			try {
				return new ResponseData(clientHttpResponse, null);
			}
			catch (IOException ignored) {
			}
		}
		return response;
	}

	private Set<LoadBalancerLifecycle> getSupportedLifecycleProcessors(String serviceId) {
		return LoadBalancerLifecycleValidator.getSupportedLifecycleProcessors(
				loadBalancerClientFactory.getInstances(serviceId, LoadBalancerLifecycle.class),
				DefaultRequestContext.class, Object.class, ServiceInstance.class);
	}

	@Override
	public URI reconstructURI(ServiceInstance serviceInstance, URI original) {
		return LoadBalancerUriTools.reconstructURI(serviceInstance, original);
	}

	@Override
	public ServiceInstance choose(String serviceId) {
		return choose(serviceId, REQUEST);
	}

    // ͨͬĸؾͻʵѡͬķ
	@Override
	public <T> ServiceInstance choose(String serviceId, Request<T> request) {
		ReactiveLoadBalancer<ServiceInstance> loadBalancer = loadBalancerClientFactory.getInstance(serviceId);
		if (loadBalancer == null) {
			return null;
		}
		Response<ServiceInstance> loadBalancerResponse = Mono.from(loadBalancer.choose(request)).block();
		if (loadBalancerResponse == null) {
			return null;
		}
		return loadBalancerResponse.getServer();
	}

	private String getHint(String serviceId) {
		LoadBalancerProperties properties = loadBalancerClientFactory.getProperties(serviceId);
		String defaultHint = properties.getHint().getOrDefault("default", "default");
		String hintPropertyValue = properties.getHint().get(serviceId);
		return hintPropertyValue != null ? hintPropertyValue : defaultHint;
	}

}

	@Bean
	@ConditionalOnMissingBean
	public ReactorLoadBalancer<ServiceInstance> reactorServiceInstanceLoadBalancer(Environment environment,
			LoadBalancerClientFactory loadBalancerClientFactory) {
		String name = environment.getProperty(LoadBalancerClientFactory.PROPERTY_NAME);
		return new RoundRobinLoadBalancer(
				loadBalancerClientFactory.getLazyProvider(name, ServiceInstanceListSupplier.class), name);
	}

package org.springframework.cloud.loadbalancer.core;

import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import reactor.core.publisher.Mono;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.DefaultResponse;
import org.springframework.cloud.client.loadbalancer.EmptyResponse;
import org.springframework.cloud.client.loadbalancer.Request;
import org.springframework.cloud.client.loadbalancer.Response;

public class RandomLoadBalancer implements ReactorServiceInstanceLoadBalancer {

	private static final Log log = LogFactory.getLog(RandomLoadBalancer.class);

	private final String serviceId;

	private ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider;

	/**
	 * @param serviceInstanceListSupplierProvider a provider of
	 * {@link ServiceInstanceListSupplier} that will be used to get available instances
	 * @param serviceId id of the service for which to choose an instance
	 */
	public RandomLoadBalancer(ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider,
			String serviceId) {
		this.serviceId = serviceId;
		this.serviceInstanceListSupplierProvider = serviceInstanceListSupplierProvider;
	}

	@SuppressWarnings("rawtypes")
	@Override
	public Mono<Response<ServiceInstance>> choose(Request request) {
		ServiceInstanceListSupplier supplier = serviceInstanceListSupplierProvider
				.getIfAvailable(NoopServiceInstanceListSupplier::new);
		return supplier.get(request).next()
				.map(serviceInstances -> processInstanceResponse(supplier, serviceInstances));
	}

	private Response<ServiceInstance> processInstanceResponse(ServiceInstanceListSupplier supplier,
			List<ServiceInstance> serviceInstances) {
		Response<ServiceInstance> serviceInstanceResponse = getInstanceResponse(serviceInstances);
		if (supplier instanceof SelectedInstanceCallback && serviceInstanceResponse.hasServer()) {
			((SelectedInstanceCallback) supplier).selectedServiceInstance(serviceInstanceResponse.getServer());
		}
		return serviceInstanceResponse;
	}

	private Response<ServiceInstance> getInstanceResponse(List<ServiceInstance> instances) {
		if (instances.isEmpty()) {
			if (log.isWarnEnabled()) {
				log.warn("No servers available for service: " + serviceId);
			}
			return new EmptyResponse();
		}
		int index = ThreadLocalRandom.current().nextInt(instances.size());

		ServiceInstance instance = instances.get(index);

		return new DefaultResponse(instance);
	}

}

package cn.itxs.ecom.order.config;

import java.util.List;
import java.util.Random;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.loadbalancer.core.ReactorServiceInstanceLoadBalancer;
import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;
import org.springframework.cloud.client.loadbalancer.DefaultResponse;
import org.springframework.cloud.client.loadbalancer.EmptyResponse;
import org.springframework.cloud.client.loadbalancer.Request;
import org.springframework.cloud.client.loadbalancer.Response;
import reactor.core.publisher.Mono;

public class ItxsRandomLoadBalancerClient implements ReactorServiceInstanceLoadBalancer {
    // б
    private ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider;

    public ItxsRandomLoadBalancerClient(ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider) {
        this.serviceInstanceListSupplierProvider = serviceInstanceListSupplierProvider;
    }

    @Override
    public Mono<Response<ServiceInstance>> choose(Request request) {
        ServiceInstanceListSupplier supplier = serviceInstanceListSupplierProvider.getIfAvailable();
        return supplier.get().next().map(this::getInstanceResponse);
    }

    /**
     * ʹȡ
     * @param instances
     * @return
     */
    private Response<ServiceInstance> getInstanceResponse(
            List<ServiceInstance> instances) {
        System.out.println("ItxsRandomLoadBalancerClient start");
        if (instances.isEmpty()) {
            return new EmptyResponse();
        }

        System.out.println("ItxsRandomLoadBalancerClient random");
        // 㷨
        int size = instances.size();
        Random random = new Random();
        ServiceInstance instance = instances.get(random.nextInt(size));

        return new DefaultResponse(instance);
    }
}

package cn.itxs.ecom.order.config;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.loadbalancer.core.ReactorServiceInstanceLoadBalancer;
import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;
import org.springframework.context.annotation.Bean;

public class CustomLoadBalancerConfiguration {

    @Bean
    public ReactorServiceInstanceLoadBalancer customLoadBalancer(ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider) {
        return new ItxsRandomLoadBalancerClient(serviceInstanceListSupplierProvider);
    }
}