发生情况

导入依赖

<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>7.12.1</version>
</dependency>

编写测试类

@SpringBootTest
class HotelAdminApplicationTests {

    private RestHighLevelClient client;

    @BeforeEach
    void setUp(){
        this.client = new RestHighLevelClient(RestClient.builder(
                HttpHost.create("http://127.0.0.1:9200")
        ));
    }

    @AfterEach
    void tearDown() throws IOException {
        this.client.close();
    }

    @Test
    void contextLoads() {
        System.out.println(client);

    }
}

解决方案

额外导入两个依赖

<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-client</artifactId>
    <version>7.12.1</version>
</dependency>

<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>7.12.1</version>
</dependency>

导入后成功运行~