elasticsearch 获取数据

ElasticSearch提供了根据索引名称，类别，文档ID来获取数据

案例

package com.et.connection;

import com.google.gson.JsonObject;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Map;

/**
 * @Author: ETJAVA
 * @CreateTime: 2024-04-07  21:26
 * @Description: TODO 读取索引
 * @Version: 1.0
 */
public class SearchIndex {

    private static String host="192.168.199.126";
    private static int port=9300; // 程序连接的端口

    public static void main(String[] args) throws UnknownHostException {

        TransportClient client = new PreBuiltTransportClient(Settings.EMPTY)
                .addTransportAddress(new TransportAddress(InetAddress.getByName(SearchIndex.host), SearchIndex.port));
        // 创建索引 返回索引相关信息
        Map<String, Object> map = createIndex(client);


        // 根据索引名称+索引类型+索引ID查询索引
        getIndex(client,String.valueOf(map.get("indexName")),String.valueOf(map.get("indexType")),String.valueOf(map.get("indexId")));


    }

    /**
     * 创建索引
     * @param client
     * @return 返回索引ID，名称，类型
     */
    private static Map<String,Object> createIndex(TransportClient client){
        Map<String,Object> map = new HashMap<>();
        // 定义要添加的数据
        JsonObject jsonObject = new JsonObject();
        jsonObject.addProperty("name","Java");
        jsonObject.addProperty("publishDate","2001-01-01");
        jsonObject.addProperty("price",99.98);

        IndexResponse indexResponse = client.prepareIndex("book", "java") // 定义索引的位置和id
                .setSource(jsonObject.toString(), XContentType.JSON) // 添加值
                .get();// 获取返回值

        map.put("indexName",indexResponse.getIndex());
        map.put("indexType",indexResponse.getType());
        map.put("indexId",indexResponse.getId());
        return map;
    }

    /**
     * 获取索引
     * @param client 连接elasticsearch的客户端对象
     * @param indexName 索引名称
     * @param indexType 索引的类型
     * @param docId 索引id
     */
    private static void getIndex(TransportClient client,String indexName,String indexType,String docId){
        GetResponse getResponse = client.prepareGet(indexName, indexType, docId).get();
        System.out.println(getResponse.getSourceAsString());// 返回json格式数据
        System.out.println(getResponse.getSource());// 返回Map格式数据
        System.out.println(new String(getResponse.getSourceAsBytes()));// 返回byte数组
    }
}