由于我用的是springboot2.3.0版本，es用的是7.4.2,但是boot中研究定义了es的版本是7.6.2，
在这里修改版本没有生效，导致项目引入了2个版本，下面是我用的api，(暂时还不知道为什么)
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>7.4.2</version>
</dependency>
然后就会发生以下错误
java.lang.IncompatibleClassChangeError: Found interface org.elasticsearch.common.bytes.BytesReference, but class was expected at org.elasticsearch.client.RequestConverters.createEntity(RequestConverters.java:689) at org.elasticsearch.client.RequestConverters.createEntity(RequestConverters.java:684) at org.elasticsearch.client.IndicesRequestConverters.createIndex(IndicesRequestConverters.java:128) at org.elasticsearch.client.RestHighLevelClient.internalPerformRequest(RestHighLevelClient.java:1760) at org.elasticsearch.client.RestHighLevelClient.performRequest(RestHighLevelClient.java:1734) at org.elasticsearch.client.RestHighLevelClient.performRequestAndParseEntity(RestHighLevelClient.java:1696) at org.elasticsearch.client.IndicesClient.create(IndicesClient.java:191) at org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate.createIndex(ElasticsearchRestTemplate.java:1248) at org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate.createIndex(ElasticsearchRestTemplate.java:1256)
查找原因，应该是2个版本原因导致的，于是就统一一下，我改不了7.4.2,那我就选择加入7.6.2，哈哈哈。
存在一个版本，然后再进行测试。
@Autowired(required = false) private RestHighLevelClient client; @Test void indexData() throws IOException { IndexRequest request = new IndexRequest("users"); request.id("1"); User u = new User(); u.setAge(11); u.setGender("男"); u.setUserName("wgr"); String s = JSON.toJSONString(u); request.source(s, XContentType.JSON); IndexResponse indexResponse = client.index(request, GulimallElasticSearchConfig.COMMON_OPTIONS); System.out.println(indexResponse); }
Found interface org.elasticsearch.common.bytes.BytesReference, but class was expected
原文：https://www.cnblogs.com/dalianpai/p/13144584.html