springboot elasticsearch报错 Error creating bean with name ‘elasticsearchClient‘

org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘elasticsearchClient’ defined in class path resource [org/springframework/boot/autoconfigure/data/elasticsearch/ElasticsearchAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.elasticsearch.client.transport.TransportClient]: Factory method ‘elasticsearchClient’ threw exception; nested exception is java.lang.IllegalStateException: availableProcessors is already set to [4], rejecting [4]

报错信息如上，创建elasticsearchClient bean失败，是因为TransportClient instantiate Failed
异常信息nested exception is java.lang.IllegalStateException让人摸不着头脑，感觉仿佛是自己什么地方配置错误，而且刚刚接触，不熟悉配置信息（其实是个坑）

原因:

Es的netty与Netty服务本身不兼容(你说bug也行)
SpringBoot 2.X 的 spring-boot-starter-data-redis 默认是以 lettuce 作为连接池的， 而在 lettuce ， elasticsearch transport 中都会依赖netty, 二者的netty 版本不一致，不能够兼容

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解决办法：

**
关于@PostConstruct注解
参考:https://blog.csdn.net/qq360694660/article/details/82877222

/**
 * @ClassName ElasticSearchConfig
 * @Description //ElasticSearchConfig
 * @Author TY
 * @Date 2021/1/26 10:05
 * @Version 1.0
 **/
@Configuration
public class ElasticSearchConfig {

    /**
     * 防止netty的bug
     * java.lang.IllegalStateException: availableProcessors is already set to [4], rejecting [4]
     */
    @PostConstruct
    void init() {
        System.setProperty("es.set.netty.runtime.available.processors", "false");
    }
}