Springboot项目添加 es 依赖后，报错：java.lang.NoClassDefFoundError: org/elasticsearch/client/core/MainResponse。
具体而言：当我新建 springboot 项目后，已经测试可以正常运行，什么都没做的情况下，添加了三个依赖：
org.springframework.boot spring-boot-starter-data-elasticsearch org.elasticsearch elasticsearch 6.5.4 org.elasticsearch.client elasticsearch-rest-high-level-client 6.5.4
再次运行，则报错如下：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'elasticsearchTemplate' defined in class path resource [org/springframework/boot/autoconfigure/data/elasticsearch/ElasticsearchDataConfiguration$RestClientConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate]: Factory method 'elasticsearchTemplate' threw exception; nested exception is java.lang.BootstrapMethodError: java.lang.NoClassDefFoundError: org/elasticsearch/client/core/MainResponse at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:638) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:944) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-5.3.12.jar:5.3.12] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.12.jar:5.3.12] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.5.6.jar:2.5.6] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754) [spring-boot-2.5.6.jar:2.5.6] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:434) [spring-boot-2.5.6.jar:2.5.6] at org.springframework.boot.SpringApplication.run(SpringApplication.java:338) [spring-boot-2.5.6.jar:2.5.6] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1343) [spring-boot-2.5.6.jar:2.5.6] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1332) [spring-boot-2.5.6.jar:2.5.6] at cn.smileyan.demo.ElasticsearchDemoApplication.main(ElasticsearchDemoApplication.java:13) [classes/:na] Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate]: Factory method 'elasticsearchTemplate' threw exception; nested exception is java.lang.BootstrapMethodError: java.lang.NoClassDefFoundError: org/elasticsearch/client/core/MainResponse at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.3.12.jar:5.3.12] at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-5.3.12.jar:5.3.12]解决方法
去掉后面两个依赖。只保留第一个即可。
即
org.springframework.boot spring-boot-starter-data-elasticsearch
虽然卸载了这些，但是功能也是可以用的。
总结踩坑无数遍，笔记千百回。如果也遇到了这个问题，并且以上方法能够解决的话，就点个赞吧，感谢！
这是真实开发场景下，已经测试过的。
Smileyan
2021.11.17 12:56
