注意了，ribbon负载均衡器将被替换

Spring Cloud Hoxton.M2 is the first release containing both blocking and non-blocking load balancer client implementations as an alternative to Netflix Ribbon which has entered maintenance mode.

To use the new `BlockingLoadBalancerClient` with a `RestTemplate` you will need to include `org.springframework.cloud:spring-cloud-loadbalancer` on your application’s classpath. The same dependency can be used in a reactive application when using `@LoadBalanced WebClient.Builder` - the only difference is that Spring Cloud will auto-configure a `ReactorLoadBalancerExchangeFilterFunction` instance. See the [documentation](https://cloud.spring.io/spring-cloud-static/spring-cloud-commons/2.2.0.M2/reference/html/#_spring_resttemplate_as_a_load_balancer_client) for additional information. The new `ReactorLoadBalancerExchangeFilterFunction` can also be autowired and passed directly to `WebClient.Builder` (see the [documentation](https://cloud.spring.io/spring-cloud-commons/reference/html/#webflux-with-reactive-loadbalancer)). For all these features, [Project Reactor](https://projectreactor.io/)-based `RoundRobinLoadBalancer` is used underneath.

@LoadBalanced
@Bean
public RestTemplate restTemplate() {
        SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
        requestFactory.setReadTimeout(env.getProperty("client.http.request.readTimeout", Integer.class, 15000));
        requestFactory.setConnectTimeout(env.getProperty("client.http.request.connectTimeout", Integer.class, 3000));
        RestTemplate rt = new RestTemplate(requestFactory);
        return rt;
}

backend:
  ribbon:
    client:
      enabled: true
    ServerListRefreshInterval: 5000

ribbon:
  ConnectTimeout: 3000
  ReadTimeout: 1000
  eager-load:
    enabled: true
    clients: cas-server,customer-server
  MaxAutoRetries: 2
  MaxAutoRetriesNextServer: 3
  OkToRetryOnAllOperations: true
  NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RoundRobinRule

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-loadbalancer</artifactId>
</dependency>

spring:
  cloud:
    loadbalancer:
      ribbon:
        enabled: false

@LoadBalanced//就不能用ip等形式来请求其他服务
@Bean
public RestTemplate restTemplate() {
        SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
        requestFactory.setReadTimeout(env.getProperty("client.http.request.readTimeout", Integer.class, 15000));
        requestFactory.setConnectTimeout(env.getProperty("client.http.request.connectTimeout", Integer.class, 3000));
        RestTemplate rt = new RestTemplate(requestFactory);
        return rt;
}