负载均衡

LoadBalancer

过程

在添加 @LoadBalanced 注解后，会启动拦截器对发起的服务调用请求进行拦截，叫做 LoadBalancerInterceptor，

它实现了 ClientHttpRequestInterceptor 接口

配置

第一种

将官方提供的 RandomLoadBalancer 注册为 Bean（不需要加 @Configuration）

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

指定对应的服务为负载均衡策略

@Configuration
@LoadBalancerClient(value = "userService", configuration = LoadBalancerConfig.class)
public class BeanConfiguration {
    @Bean
    @LoadBalanced
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

OpenFeign

配置

添加依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
    <version>4.0.1</version>
</dependency>

在启动类上添加注解

@SpringBootApplication
@EnableFeignClients
public class BorrowApplication {
    public static void main(String[] args) {
        SpringApplication.run(BorrowApplication.class);
    }
}

创建对应服务的接口类