以下是一个简单的Maven工程和Spring demo案例,演示如何使用Java调用Elasticsearch。

配置Maven依赖

在pom.xml文件中添加以下依赖:

org.elasticsearch elasticsearch 6.5.4 org.elasticsearch.client transport 6.5.4 org.elasticsearch.client rest 6.5.4

创建Elasticsearch连接

创建一个Elasticsearch连接配置类,用于连接Elasticsearch集群。示例代码如下:

@Configuration
public class ElasticsearchConfig {

private static final String HOST = "localhost";private static final int PORT = 9300;@Beanpublic RestHighLevelClient restHighLevelClient() {    RestClientBuilder builder = RestClient.builder(new HttpHost(HOST, PORT));    RestHighLevelClient client = new RestHighLevelClient(builder);    return client;}

}

创建Elasticsearch操作类

创建一个Elasticsearch操作类,用于执行Elasticsearch的操作。示例代码如下:

@Componentpublic class ElasticsearchService {private RestHighLevelClient client;@Autowiredpublic ElasticsearchService(RestHighLevelClient client) {    this.client = client;}public void createIndex(String indexName) throws IOException {    CreateIndexRequest request = new CreateIndexRequest(indexName);    client.indices().create(request, RequestOptions.DEFAULT);}public void deleteIndex(String indexName) throws IOException {    DeleteIndexRequest request = new DeleteIndexRequest(indexName);    client.indices().delete(request, RequestOptions.DEFAULT);}public void insert(String indexName, String id, String jsonString) throws IOException {    IndexRequest request = new IndexRequest(indexName);    request.id(id);    request.source(jsonString, XContentType.JSON);    IndexResponse response = client.index(request, RequestOptions.DEFAULT);}public void update(String indexName, String id, String jsonString) throws IOException {UpdateRequest request = new UpdateRequest(indexName, id);        request.doc(jsonString, XContentType.JSON);        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);    }public void delete(String indexName, String id) throws IOException {    DeleteRequest request = new DeleteRequest(indexName, id);    DeleteResponse response = client.delete(request, RequestOptions.DEFAULT);}public SearchHits search(String indexName, QueryBuilder queryBuilder) throws IOException {    SearchRequest searchRequest = new SearchRequest(indexName);    SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();    searchSourceBuilder.query(queryBuilder);    searchRequest.source(searchSourceBuilder);    SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);    SearchHits hits = response.getHits();    return hits;}}4. 创建Spring Boot控制器创建一个Spring Boot控制器,在其中调用Elasticsearch操作类执行Elasticsearch操作。示例代码如下:@RestControllerpublic class ElasticsearchController {@Autowiredprivate ElasticsearchService elasticsearchService;@GetMapping("/createIndex")public String createIndex() throws IOException {    elasticsearchService.createIndex("my_index");    return "Index created successfully";}@GetMapping("/deleteIndex")public String deleteIndex() throws IOException {    elasticsearchService.deleteIndex("my_index");    return "Index deleted successfully";}@PostMapping("/insert")public String insert() throws IOException {    String jsonString = "{\"title\":\"Java Programming\",\"author\":\"John Doe\"}";    elasticsearchService.insert("my_index", "1", jsonString);    return "Document inserted successfully";}@PostMapping("/update")public String update() throws IOException {    String jsonString = "{\"title\":\"Java Programming\",\"author\":\"Jane Doe\"}";    elasticsearchService.update("my_index", "1", jsonString);    return "Document updated successfully";}@GetMapping("/delete")public String delete() throws IOException {    elasticsearchService.delete("my_index", "1");    return "Document deleted successfully";}@GetMapping("/search")public SearchHits search() throws IOException {    QueryBuilder queryBuilder = QueryBuilders.matchQuery("title", "Java");    SearchHits hits = elasticsearchService.search("my_index", queryBuilder);    return hits;}}

以上代码演示了如何创建Elasticsearch连接、执行Elasticsearch

操作,以及在Spring Boot控制器中调用Elasticsearch操作类执行操作。

测试

运行Spring Boot应用程序,并访问以下URL以执行相应的操作:

/createIndex:创建名为“my_index”的索引。

/deleteIndex:删除名为“my_index”的索引。

/insert:向名为“my_index”的索引插入一条文档。

/update:更新名为“my_index”的索引中的文档。

/delete:从名为“my_index”的索引中删除文档。

/search:从名为“my_index”的索引中搜索匹配“Java”的文档。

可以使用Postman或类似的工具进行测试。

以上就是一个基本的Maven工程和Spring demo案例,演示了如何使用Java调用Elasticsearch。这只是一个简单的示例,实际应用中可能需要更复杂和细致的实现。