```java import lombok.extern.slf4j.Slf4j; import org.apache.http.HttpHost; import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest; import org.elasticsearch.action.support.master.AcknowledgedResponse; import org.elasticsearch.client.RequestOptions; import org.elasticsearch.client.RestClient; import org.elasticsearch.client.RestHighLevelClient; import org.elasticsearch.client.indices.CreateIndexRequest; import org.elasticsearch.client.indices.CreateIndexResponse; import org.elasticsearch.client.indices.GetIndexRequest; import org.elasticsearch.client.indices.GetIndexResponse; import org.junit.Test; import java.io.IOException; @Slf4j public class IndexOperation { /** * 創建索引 */ @Test public void createIndex() throws IOException { //獲取elasticsearch客戶端 RestHighLevelClient client = new RestHighLevelClient( RestClient.builder(new HttpHost("localhost", 9200, "http")) ); //創建索引，如果索引已經存在則拋出異常 CreateIndexRequest request = new CreateIndexRequest("user"); //發送請求并獲取響應 CreateIndexResponse response = client.indices().create(request, RequestOptions.DEFAULT); boolean acknowledged = response.isAcknowledged(); //創建結果：true log.info("創建結果：{}", acknowledged); //關閉連接 client.close(); } /** * 查詢索引 */ @Test public void getIndex() throws IOException { RestHighLevelClient client = new RestHighLevelClient( RestClient.builder(new HttpHost("localhost", 9200, "http")) ); //查詢索引 GetIndexRequest request = new GetIndexRequest("user"); GetIndexResponse response = client.indices().get(request, RequestOptions.DEFAULT); //size: 1, indices: [user] log.info("size: {}, indices: {}", response.getIndices().length, response.getIndices()); client.close(); } /** * 刪除索引 */ @Test public void deleteIndex() throws IOException { RestHighLevelClient client = new RestHighLevelClient( RestClient.builder(new HttpHost("localhost", 9200, "http")) ); //刪除索引 DeleteIndexRequest request = new DeleteIndexRequest("user"); //發送請求并獲取響應 AcknowledgedResponse response = client.indices().delete(request, RequestOptions.DEFAULT); //操作結果：true log.info("操作結果：{}", response.isAcknowledged()); //關閉連接 client.close(); } } ```