elasticsearch 类document

Elasticsearch 是一个开源的分布式搜索和分析引擎，它使用倒排索引来实现高效的全文搜索。在 Elasticsearch 中，文档（Document）是最基本的数据单元。每个文档都有一个唯一的标识（ID），并且由多个字段组成。

一个文档可以是任何形式的结构化数据，通常以 JSON 格式表示。每个字段都有一个字段名和相应的值。字段可以是简单的值（如字符串、数字、布尔值等），也可以是复杂的结构（如嵌套对象、数组等）。

在 Elasticsearch 中，文档是存储、索引和搜索的基本单位。你可以将文档插入到索引中，然后通过各种查询来搜索和检索这些文档。每个文档都可以独立地进行索引和更新，而且可以根据需要进行分片和复制，以支持高吞吐量和可扩展性。

总结来说，Elasticsearch 的文档是用于存储和检索数据的基本单位，它具有灵活的数据结构和强大的搜索功能。

相关问题

elasticsearch java类document

在 Elasticsearch 的 Java 客户端中，有一个名为 `org.elasticsearch.client.document.DocumentClient` 的类，用于执行与文档相关的操作。这个类提供了一系列方法，可以用来索引、获取、更新和删除文档。下面是一个简单的示例：

import org.elasticsearch.action.get.GetRequest;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.action.update.UpdateRequest;
import org.elasticsearch.action.update.UpdateResponse;
import org.elasticsearch.action.delete.DeleteRequest;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;

public class DocumentExample {
    private RestHighLevelClient client;

    public DocumentExample(RestHighLevelClient client) {
        this.client = client;
    }

    public void indexDocument(String index, String id, String json) throws IOException {
        IndexRequest request = new IndexRequest(index)
            .id(id)
            .source(json, XContentType.JSON);
        
        IndexResponse response = client.index(request, RequestOptions.DEFAULT);
        System.out.println(response);
    }

    public void getDocument(String index, String id) throws IOException {
        GetRequest request = new GetRequest(index, id);
        
        GetResponse response = client.get(request, RequestOptions.DEFAULT);
        System.out.println(response);
    }

    public void updateDocument(String index, String id, String json) throws IOException {
        UpdateRequest request = new UpdateRequest(index, id)
            .doc(json, XContentType.JSON);
        
        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        System.out.println(response);
    }

    public void deleteDocument(String index, String id) throws IOException {
        DeleteRequest request = new DeleteRequest(index, id);
        
        DeleteResponse response = client.delete(request, RequestOptions.DEFAULT);
        System.out.println(response);
    }
}

以上示例展示了如何使用 `DocumentClient` 类来执行索引、获取、更新和删除文档的操作。你可以根据自己的需求调用这些方法，并根据需要处理相应的响应。请注意，需要先创建一个 `RestHighLevelClient` 实例，并将其传递给 `DocumentExample` 的构造函数中，以便与 Elasticsearch 集群进行交互。

elasticsearch通用工具类

以下是一个基本的 Elasticsearch 工具类，可以用于与 Elasticsearch 交互：

import org.apache.http.HttpHost;
import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.bulk.BulkResponse;
import org.elasticsearch.action.delete.DeleteRequest;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.action.get.GetRequest;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.QueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.builder.SearchSourceBuilder;

import java.io.IOException;
import java.util.List;
import java.util.Map;

public class ElasticsearchUtil {

    private RestHighLevelClient client;

    public ElasticsearchUtil(String host, int port) {
        client = new RestHighLevelClient(RestClient.builder(new HttpHost(host, port, "http")));
    }

    public void close() throws IOException {
        client.close();
    }

    public boolean indexExists(String index) throws IOException {
        return client.indices().exists(new GetIndexRequest(index), RequestOptions.DEFAULT);
    }

    public boolean createIndex(String index) throws IOException {
        CreateIndexRequest request = new CreateIndexRequest(index);
        request.settings(Settings.builder()
                .put("index.number_of_shards", 3)
                .put("index.number_of_replicas", 2)
        );
        request.mapping("properties", "{\n" +
                "  \"name\": {\n" +
                "    \"type\": \"text\"\n" +
                "  },\n" +
                "  \"age\": {\n" +
                "    \"type\": \"integer\"\n" +
                "  }\n" +
                "}", XContentType.JSON);
        request.alias(new Alias("my_alias"));

        CreateIndexResponse response = client.indices().create(request, RequestOptions.DEFAULT);
        return response.isAcknowledged();
    }

    public boolean deleteIndex(String index) throws IOException {
        DeleteIndexRequest request = new DeleteIndexRequest(index);
        AcknowledgedResponse response = client.indices().delete(request, RequestOptions.DEFAULT);
        return response.isAcknowledged();
    }

    public boolean documentExists(String index, String id) throws IOException {
        GetRequest getRequest = new GetRequest(index, id);
        getRequest.fetchSourceContext(new FetchSourceContext(false));
        getRequest.storedFields("_none_");
        return client.exists(getRequest, RequestOptions.DEFAULT);
    }

    public boolean createDocument(String index, String id, Map<String, Object> source) throws IOException {
        IndexRequest request = new IndexRequest(index);
        if (id != null) {
            request.id(id);
        }
        request.source(source);
        IndexResponse response = client.index(request, RequestOptions.DEFAULT);
        return response.getResult() == DocWriteResponse.Result.CREATED;
    }

    public boolean updateDocument(String index, String id, Map<String, Object> source) throws IOException {
        UpdateRequest request = new UpdateRequest(index, id);
        request.doc(source);
        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        return response.getResult() == DocWriteResponse.Result.UPDATED;
    }

    public boolean deleteDocument(String index, String id) throws IOException {
        DeleteRequest request = new DeleteRequest(index, id);
        DeleteResponse response = client.delete(request, RequestOptions.DEFAULT);
        return response.getResult() == DocWriteResponse.Result.DELETED;
    }

    public Map<String, Object> getDocument(String index, String id) throws IOException {
        GetRequest getRequest = new GetRequest(index, id);
        GetResponse response = client.get(getRequest, RequestOptions.DEFAULT);
        if (response.isExists()) {
            return response.getSource();
        } else {
            return null;
        }
    }

    public List<Map<String, Object>> searchDocument(String index, String field, String value) throws IOException {
        QueryBuilder queryBuilder = QueryBuilders.matchQuery(field, value);
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.query(queryBuilder);
        SearchRequest searchRequest = new SearchRequest(index);
        searchRequest.source(sourceBuilder);
        SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
        List<Map<String, Object>> result = new ArrayList<>();
        for (SearchHit hit : searchResponse.getHits().getHits()) {
            result.add(hit.getSourceAsMap());
        }
        return result;
    }

    public boolean bulkCreateDocuments(String index, List<Map<String, Object>> sources) throws IOException {
        BulkRequest request = new BulkRequest();
        for (Map<String, Object> source : sources) {
            IndexRequest indexRequest = new IndexRequest(index);
            indexRequest.source(source);
            request.add(indexRequest);
        }
        BulkResponse response = client.bulk(request, RequestOptions.DEFAULT);
        return !response.hasFailures();
    }

    public boolean bulkUpdateDocuments(String index, List<Map<String, Object>> sources) throws IOException {
        BulkRequest request = new BulkRequest();
        for (Map<String, Object> source : sources) {
            String id = (String) source.remove("id");
            UpdateRequest updateRequest = new UpdateRequest(index, id);
            updateRequest.doc(source);
            request.add(updateRequest);
        }
        BulkResponse response = client.bulk(request, RequestOptions.DEFAULT);
        return !response.hasFailures();
    }

    public boolean bulkDeleteDocuments(String index, List<String> ids) throws IOException {
        BulkRequest request = new BulkRequest();
        for (String id : ids) {
            DeleteRequest deleteRequest = new DeleteRequest(index, id);
            request.add(deleteRequest);
        }
        BulkResponse response = client.bulk(request, RequestOptions.DEFAULT);
        return !response.hasFailures();
    }

}

这个工具类使用 Elasticsearch 的 Java High Level REST Client，支持创建、删除索引，增删改查文档，以及批量操作。