Spring Cloud Nacos 2021使用LoadBalancer做负载均衡

news2025/8/11 8:30:04

项目源码：https://download.csdn.net/download/weixin_42950079/87150709

Spring Cloud Nacos 2021 移除了 Ribbon，在Spring Cloud Commons 项目中添加了 Spring Cloud LoadBalancer 作为新的负载均衡器

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
    <version>2021.0.1.0</version>
</dependency>

<!-- loadbalancer负载均衡 -->
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-loadbalancer</artifactId>
</dependency>

LoadBalancer负载均衡策略

LoadBalancer 的负载均衡策略没有 Ribbon 那么丰富，只提供了RandomLoadBalancer、NacosLoadBalancer、RoundRobinLoadBalancer，在不指定的时候默认使用RoundRobinLoadBalancer轮询负载均衡策略。 👉👉👉推荐使用整合 Ribbon 的方式来实现负载均衡。

RandomLoadBalancer ：基于随机访问的负载均衡策略
NacosLoadBalancer：基于Nacos权重的负载均衡策略
RoundRobinLoadBalancer：基于轮询的负载均衡策略

切换LoadBalancer负载均衡策略

使用基于随机访问的负载均衡策略，注意返回类型是 ReactorLoadBalancer<ServiceInstance>

@Configuration
public class CustomLoadBalancerConfiguration {

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

}

使用基于轮询的负载均衡策略，注意返回类型是 ReactorLoadBalancer<ServiceInstance>

@Configuration
public class CustomLoadBalancerConfiguration {

    // 参考 NacosLoadBalancerClientConfiguration
    @Bean
    public ReactorLoadBalancer<ServiceInstance> roundRobinLoadBalancer(Environment environment, LoadBalancerClientFactory loadBalancerClientFactory) {
        String name = environment.getProperty(LoadBalancerClientFactory.PROPERTY_NAME);

        return new RoundRobinLoadBalancer(loadBalancerClientFactory.getLazyProvider(name, ServiceInstanceListSupplier.class), name);
    }

}

使用负载均衡策略

在启动类上添加@LoadBalancerClient注解，指定xxx服务使用xxx负载均衡策略。

@SpringBootApplication
@LoadBalancerClients(
        @LoadBalancerClient(value = "stock-service", configuration = CustomLoadBalancerConfiguration.class)
)
public class Order8010Application {

    public static void main(String[] args) {
        SpringApplication.run(Order8010Application.class);
        System.out.println("order8010 --> 项目启动成功");
    }

}