[大数据]Java 操作ElasticSearch API 大全，涵盖所有操作方式

内容简介：包括TransportClient、Low Level Rest Client、High Level Rest Cliet的详细用法，此外还包括高亮搜索、聚合搜索、SQL搜索、SpringDataElasticSearch的Template搜索，Repositories搜索等；涵盖Java操作ElasticSearch的所有API！

一、ElasticSearch Java API

ElasticSearch官方支持当下几乎所有流行编程语言，如Java、JavaScript、Ruby、Go、.Net、Python等。并且在ElasticSearch官方中都有非常详细的使用案例介绍：

ElasticSearch的客户端工具官方文档：https://www.elastic.co/guide/en/elasticsearch/client/index.html

在使用Java客户端操作ElasticSearch时，官方提供有Java Transport Client和Java REST Client方式；其中Java REST Client分为Java Low Level REST Client和Java High Level REST Client两种方式；

• Java Transport Client：ES的早期连接工具，TransportClient通过TCP方式访问ES，功能强大，上手简单，ElasticSearch早期推出的Java客户端工具；在7.0版本中不再建议使用，将会在8.0版本中被删除；
• Java REST Client：5.0版本新推出的Java客户端工具，RestClient方式通过http访问ES，依赖于JDK1.8（官方推荐）；
  • Java Low Level REST Client：官方的低级客户端。它允许通过http与一个Elasticsearch集群通信。将请求的编组和响应的反编组工作留给用户自己处理。它兼容所有的Elasticsearch的版本。
  • Java High Level REST Client：官方的高级客户端。它基于低级客户端，它暴露了API特定的方法，并负责处理请求编组和响应非编组。

Tips：需要注意的是：TransportClient的默认端口是9300，而Rest Client的默认端口是9200

官方参考资料：

• Java Transport Client：https://www.elastic.co/guide/en/elasticsearch/client/java-api/7.6/index.html
• Java Low Level REST Client：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-low.html
• Java High Level REST Client：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-high.html

1.1 搭建环境

1.1.1 Maven依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.es</groupId>
    <artifactId>01_ElasticSearch_API</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!--es依赖-->
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.6.2</version>
        </dependency>

        <!--es依赖-->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>transport</artifactId>
            <version>7.6.2</version>
        </dependency>

        <!--lombok插件-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.10</version>
        </dependency>

        <!--json转换工具-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.8.1</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.1</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

1.1.2 实体类

package com.es.entity;

/**
 * @author lscl
 * @version 1.0
 * @intro:
 */

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Goods {
    private String id;
    private String name;
    private String title;
    private Double price;
    private String[] category;
}

1.1.3 建立连接

package com.es.demo;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.Test;

/**
 * @author lscl
 * @version 1.0
 * @intro:
 */
public class Demo01_ES_Connection {

    /*
        TransportClient:建立连接
        官网案例: https://www.elastic.co/guide/en/elasticsearch/client/java-api/7.6/transport-client.html
     */
    @Test
    public void test1() throws Exception {

        // 创建Client连接对象(指定集群名称)
        Settings settings = Settings.builder().put("cluster.name", "my-cluster").build();

        // 客户端对象
        TransportClient client = new PreBuiltTransportClient(settings);

        System.out.println(client);

        // 释放资源
        client.close();
    }

    /*
        Low Level REST Client: 建立连接
        官网案例: https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-low-usage-initialization.html
     */
    @Test
    public void test2() throws Exception {
        RestClient restClient = RestClient.builder(
                new HttpHost("localhost", 9200, "http")
        ).build();

        System.out.println(restClient);
    }


    /*
        High Level REST Client: 建立连接
        官网案例: https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-high-getting-started-initialization.html
    */
    @Test
    public void test3() throws Exception {
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http")
                )
        );

        System.out.println(client);
    }

}

1.2 TransportClient 的用法

• 1）TransportClient 使用9300端口远程连接到 Elasticsearch 集群，客户端并不加入集群，而是通过获取单个或者多个transport地址来以轮询的方式与他们通信。

• 2）TransportClient使用传输协议与Elasticsearch节点通信，如果客户端的版本和与其通信的ES实例的版本不同，就会出现兼容性问题。而low-level REST使用的是HTTP协议，可以与任意版本ES集群通信。high-level REST是基于low-level REST的。

ElasticSearch官方关于TransportClient的使用方法：https://www.elastic.co/guide/en/elasticsearch/client/java-api/7.6/index.html

1.2.1 索引相关

TransportClient 索引相关API：https://www.elastic.co/guide/en/elasticsearch/client/java-api/7.6/java-admin-indices.html

要进行索引的管理必须获取到IndicesAdminClient对象来进行索引管理：

// 创建客户端管理对象
AdminClient adminClient = transportClient.admin();

IndicesAdminClient indices = adminClient.indices();

• IndicesAdminClient类对象索引的管理有两种方式：

  • 1）prepareXxx相关方法：

    • prepareCreate：创建索引
    • prepareDelete：删除索引
    • prepareUpdateSettings：修改索引配置
    • prepareGetIndex：查询索引信息
    • prepareGetSettings：查询索引配置信息

  • 2）封装Request相关方法：

    • create：创建索引

    CreateIndexRequest具体用法：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-high-create-index.html

    • delete：删除索引

    DeleteIndexRequest具体用法：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-high-delete-index.html

    • updateSettings：修改索引

    UpdateSettingsRequest具体用法：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-high-indices-put-settings.html

    • getIndex：查询索引信息

    GetIndexRequest具体用法：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-high-indices-exists.html

1）prepareXxx相关方法

• 代码示例：

package com.es.demo;

import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
import org.elasticsearch.action.admin.indices.get.GetIndexResponse;
import org.elasticsearch.action.admin.indices.mapping.put.PutMappingRequest;
import org.elasticsearch.action.admin.indices.settings.get.GetSettingsResponse;
import org.elasticsearch.client.AdminClient;
import org.elasticsearch.client.IndicesAdminClient;
import org.elasticsearch.client.Requests;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.net.InetAddress;
import java.util.Arrays;

/**
 * @author lscl
 * @version 1.0
 * @intro: Java操作ES  TransportClient方式 索引管理
 * 官网相关案例: https://www.elastic.co/guide/en/elasticsearch/client/java-api/7.6/java-admin-indices.html
 */
public class Demo02_Index_TransportClient_Prepare {

    // 创建Client连接对象
    private Settings settings;

    // es客户端对象
    private TransportClient client;

    @Before
    public void before() throws Exception {

        // 创建Client连接对象
        settings = Settings.builder().put("cluster.name", "elasticsearch").build();

        // 客户端对象
        client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
    }

    @After
    public void after() throws Exception {
        client.close();
    }

    // 创建索引
    @Test
    public void test1() throws Exception {

        // 创建客户端管理对象
        AdminClient adminClient = client.admin();

        // 获取索引操作对象
        IndicesAdminClient indices = adminClient.indices();

        // 创建索引
        indices.prepareCreate("goodsindex")
                .setSettings(
                        Settings.builder()
                                // primary shard
                                .put("index.number_of_shards", 3)
                                // replica shard
                                .put("index.number_of_replicas", 1)
                ).get();        // 执行创建

        // 快速创建索引
//        client.admin().indices().prepareCreate("goodsindex").get();
    }

    // 创建映射
    @Test
    public void test2() throws Exception {
        /*
             创建一个Content构建对象
             {
                "_doc":{
                    "properties": {
                        "id":{
                            "type":"integer",
                            "store":"true"
                        },
                        "name":{
                            "type":"text",
                            "store":"true"
                        },
                        "title":{
                            "type":"text",
                            "store":"true"
                        },
                        "price":{
                            "type":"double"
                        },
                        "category":{
                            "fielddata": true,
                            "type":"object"
                        }
                    }
                }
             }
         */
        XContentBuilder builder = XContentFactory.jsonBuilder()
                .startObject()
                .startObject("_doc")
                .startObject("properties")
                .startObject("id")
                .field("type", "integer")
                .field("store", "true")
                .endObject()
                .startObject("name")
                .field("type", "text").field("store", "true").field("analyzer", "standard")
                .endObject()
                .startObject("title")
                .field("type", "text").field("store", "true").field("analyzer", "standard")
                .endObject()
                .startObject("price")
                .field("type", "double")
                .endObject()
                .startObject("category")
                .field("type", "text").field("fielddata", true)
                .endObject()
                .endObject()
                .endObject()
                .endObject();

        // 创建映射
        PutMappingRequest mapping = Requests.putMappingRequest("goodsindex")      // 该索引必须存在
                .type("_doc").source(builder);

        // 索引操作对象
        IndicesAdminClient indices = client.admin().indices();

        // 添加映射
        indices.putMapping(mapping).get();

    }

    // 删除索引
    @Test
    public void test3() throws Exception {
        // 获取索引操作对象
        IndicesAdminClient indices = client.admin().indices();
        // 删除索引
        indices.prepareDelete("goodsindex").get();
    }


    // 更新索引
    @Test
    public void test4() throws Exception {
        // 获取索引操作对象
        IndicesAdminClient indices = client.admin().indices();

        // 执行更改
        indices.prepareUpdateSettings("goodsindex")
                .setSettings(
                        Settings.builder().put("index.number_of_replicas", 1)
                ).get();
    }

    // 查询索引信息
    @Test
    public void test5() throws Exception {
        // 获取索引操作对象
        IndicesAdminClient indices = client.admin().indices();

        // 制作查询
        GetIndexResponse indexResponse = indices.prepareGetIndex().get();

        // 获取索引名称
        String[] indexNames = indexResponse.getIndices();
        System.out.println("indexNames: " + Arrays.toString(indexNames));
    }


    // 查询索引配置
    @Test
    public void test6() throws Exception {
        // 获取索引操作对象
        IndicesAdminClient indices = client.admin().indices();

        // 执行查询
        GetSettingsResponse response = indices.prepareGetSettings("goodsindex").get();

        for (ObjectObjectCursor<String, Settings> cursor : response.getIndexToSettings()) {
            // 索引名称
            String index = cursor.key;

            // 索引配置信息
            Settings settings = cursor.value;

            // primary shard
            Integer shards = settings.getAsInt("index.number_of_shards", null);

            // replica shard
            Integer replicas = settings.getAsInt("index.number_of_replicas", null);

            System.out.println("index: " + index);
            System.out.println("settings: " + settings);
            System.out.println("shards: " + shards);
            System.out.println("replicas: " + replicas);
        }
    }
}

2）封装Request相关方法

• 代码示例：

package com.es.demo;

import org.elasticsearch.action.admin.indices.create.CreateIndexRequest;
import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
import org.elasticsearch.action.admin.indices.get.GetIndexRequest;
import org.elasticsearch.action.admin.indices.get.GetIndexResponse;
import org.elasticsearch.action.admin.indices.settings.put.UpdateSettingsRequest;
import org.elasticsearch.client.AdminClient;
import org.elasticsearch.client.IndicesAdminClient;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

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

/**
 * @author lscl
 * @version 1.0
 * @intro: Java操作ES  TransportClient方式 索引管理
 */
public class Demo03_Index_TransportClient {

    // 创建Client连接对象
    private Settings settings;

    // es客户端对象
    private TransportClient client;

    @Before
    public void before() throws Exception {

        // 创建Client连接对象
        settings = Settings.builder().put("cluster.name", "elasticsearch").build();

        // 客户端对象
        client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
    }

    @After
    public void after() throws Exception {
        client.close();
    }

    // 创建索引
    @Test
    public void test1() throws Exception {

        // 创建客户端管理对象
        AdminClient adminClient = client.admin();

        // 获取索引操作对象
        IndicesAdminClient indices = adminClient.indices();

        // 创建索引请求对象(具体用法: https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-high-create-index.html)
        CreateIndexRequest createIndexRequest = new CreateIndexRequest("goodsindex");

        // 分片配置
        createIndexRequest.settings(
                Settings.builder()
                        .put("index.number_of_shards", 3)
                        .put("index.number_of_replicas", 2)
        );

//        createIndexRequest.mapping()      // 设置映射

        // 发送请求
        indices.create(createIndexRequest).get();
    }


    // 删除索引
    @Test
    public void test2() throws Exception {
        // 获取索引操作对象
        IndicesAdminClient indices = client.admin().indices();

        indices.delete(new DeleteIndexRequest("goodsindex")).get();
    }


    // 更新索引
    @Test
    public void test3() throws Exception {
        // 获取索引操作对象
        IndicesAdminClient indices = client.admin().indices();

        // 索引配置修改对象(具体用法: https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-high-indices-put-settings.html)
        UpdateSettingsRequest updateSettingsRequest = new UpdateSettingsRequest();

        // 设置配置信息
        /*updateSettingsRequest.settings(
                Settings.builder()
                        .put("index.number_of_replicas", 1)
                        .build()
        );*/

        // 也可以使用Map
        HashMap<String, Object> settingsParams = new HashMap<>();
        settingsParams.put("index.number_of_replicas", 1);

        // 设置配置信息
        updateSettingsRequest.settings(settingsParams);

        indices.updateSettings(updateSettingsRequest).get();
    }

    // 查询索引
    @Test
    public void test4() throws Exception {
        // 获取索引操作对象
        IndicesAdminClient indices = client.admin().indices();

        // 索引查询对象
        GetIndexRequest getIndexRequest = new GetIndexRequest();

        // 执行查询,获取结果集
        GetIndexResponse indexResponse = indices.getIndex(getIndexRequest).get();

        // 获取索引名称
        String[] indexNames = indexResponse.getIndices();

        System.out.println("indexNames: " + indexNames);

//        indexResponse.getAliases()            // 获取别名
//        indexResponse.getMappings()           // 获取映射
//        indexResponse.getSettings()           // 获取配置信息
    }
}

1.2.2 文档相关

TransportClient文档管理相关API：https://www.elastic.co/guide/en/elasticsearch/client/java-api/7.6/index.html

同样，对于文档管理相关功能的API在ElasticSearch官网中提供有两种方式：

• 1）prepareXxx相关方法：
  • prepareIndex：创建文档
  • prepareDelete：删除文档
  • prepareUpdate：修改文档
  • prepareGet：查询文档
• 2）直接功能方法：
  • index：创建文档
  • delete：删除文档
  • update：修改文档
  • get：查询文档

1）preapeXxx相关方法

• 代码示例：

package com.es.demo;

import com.es.entity.Goods;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

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

/**
 * @author lscl
 * @version 1.0
 * @intro: Java操作ES  TransportClient方式 文档管理
 */
public class Demo04_Document_TransportClient_Prepare {
    // 创建Client连接对象
    private Settings settings;

    // es客户端对象
    private TransportClient client;

    @Before
    public void before() throws Exception {
        // 创建Client连接对象
        settings = Settings.builder().put("cluster.name", "elasticsearch").build();

        // 客户端对象
        client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
    }

    @After
    public void after() throws Exception {
        client.close();
    }

    // 新增文档
    @Test
    public void test1() throws Exception {

        // 准备json数据
        Goods goods = new Goods("1",
                "xiaomi shouji",
                "xiaomi 5G paizhao shouji",
                2899.0D,
                new String[]{"5G", "paizhao"}
        );

        ObjectMapper objectMapper = new ObjectMapper();

        // 转换为JSON字符串
        String goodsJson = objectMapper.writeValueAsString(goods);

        // 执行请求
        client.prepareIndex("goodsindex", "_doc", "1").setSource(goodsJson, XContentType.JSON).get();
    }

    // XContentBuilder方式构建文档
    @Test
    public void test2() throws Exception {
        //创建文档信息
        XContentBuilder builder = XContentFactory.jsonBuilder()
                .startObject()
                .field("id", "2")
                .field("name", "huawei shouji")
                .field("title", "huawei 4G youxi shouji")
                .field("price", 988)
                .field("category", new String[]{"4G", "youxi"})
                .endObject();

        // 建立文档对象
        client.prepareIndex("goodsindex", "_doc", "2").setSource(builder).get();
    }

    // 删除文档
    @Test
    public void test3() throws Exception {
        client.prepareDelete("goodsindex", "_doc", "1").get();
    }


    // 修改文档
    @Test
    public void test4() throws Exception {

        Goods goods = new Goods("2",
                "lianxian shouji",
                "lianxiang 5G youxi shouji",
                3899.0D,
                new String[]{"5G", "youxi"}
        );

        ObjectMapper om = new ObjectMapper();

        // 转换为JSON字符串
        String goodsJson = om.writeValueAsString(goods);

        // 执行请求
        client.prepareUpdate("goodsindex", "_doc", "2").setDoc(goodsJson, XContentType.JSON).get();
    }

    // 查询文档
    @Test
    public void test5() throws Exception {

        // 执行查询
        GetResponse response = client.prepareGet("goodsindex", "_doc", "1").get();

        // 查询结果以Map形式返回
        Map<String, Object> sourceAsMap = response.getSourceAsMap();
        System.out.println("map: " + sourceAsMap);

        // 查询结果以Json字符串形式返回
        String jsonStr = response.getSourceAsString();
        System.out.println("jsonStr: " + jsonStr);
    }
}

2）封装Request相关方法

• 代码示例：

package com.es.demo;

import com.es.entity.Goods;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.elasticsearch.action.delete.DeleteRequest;
import org.elasticsearch.action.get.GetRequest;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.update.UpdateRequest;
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 org.junit.After;
import org.junit.Before;
import org.junit.Test;

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

/**
 * @author lscl
 * @version 1.0
 * @intro: Java操作ES  TransportClient方式 文档管理
 * 官网相关案例:
 */
public class Demo05_Document_TransportClient {
    // 创建Client连接对象
    private Settings settings;

    // es客户端对象
    private TransportClient client;

    @Before
    public void before() throws Exception {
        // 创建Client连接对象
        settings = Settings.builder().put("cluster.name", "elasticsearch").build();

        // 客户端对象
        client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
    }

    @After
    public void after() throws Exception {
        client.close();
    }

    // 新增文档
    @Test
    public void test1() throws Exception {

        // 准备json数据
        Goods goods = new Goods("1",
                "xiaomi shouji",
                "xiaomi 5G paizhao shouji",
                2899.0D,
                new String[]{"5G", "paizhao"}
        );

        ObjectMapper objectMapper = new ObjectMapper();

        String goodsJson = objectMapper.writeValueAsString(goods);

        // 创建索引请求对象
        IndexRequest indexRequest = new IndexRequest("goodsindex", "_doc", "1");

        // 传递json数据
        indexRequest.source(goodsJson, XContentType.JSON);

        // 执行请求
        client.index(indexRequest).get();
    }

    // 删除文档
    @Test
    public void test2() throws Exception {
        client.delete(new DeleteRequest("goodsindex", "_doc", "1")).get();
    }


    // 修改文档
    @Test
    public void test3() throws Exception {

        // 准备Update请求
        UpdateRequest updateRequest = new UpdateRequest("goodsindex", "_doc", "2");

        Goods goods = new Goods("1",
                "lianxian shouji",
                "lianxiang 5G youxi shouji",
                3899.0D,
                new String[]{"5G", "youxi"}
        );

        ObjectMapper om = new ObjectMapper();

        // 设置新文档
        updateRequest.doc(om.writeValueAsString(goods), XContentType.JSON);

        // 执行update请求
        client.update(updateRequest).get();
    }

    // 查询文档
    @Test
    public void test4() throws Exception {

        // 准备一个get请求
        GetRequest getRequest = new GetRequest("goodsindex", "_doc", "2");
        // 执行get请求
        GetResponse res = client.get(getRequest).get();

        // 获取map数据
        Map<String, Object> goodsMap = res.getSource();
        System.out.println(goodsMap);

        // 获取json数据
        String goodsJson = res.getSourceAsString();
        System.out.println(goodsJson);
    }
}

1.2.3 搜索相关功能

• 准备数据：

DELETE goodsindex

POST /goodsindex/_doc/1
{
  "name":"huawei shouji",
  "title":"huawei 4G quanmianping youxi shouji",
  "price":4899,
  "category":["youxi","4G","quanmianping"]
}

POST /goodsindex/_doc/2
{
  "name":"vivo shouji",
  "title":"vivo 5G paizhao shouji",
  "price":2899,
  "category":["5G","paizhao"]
}

POST /goodsindex/_doc/3
{
  "name":"oppo shouji",
  "title":"oppo 5G paizhao shouji",
  "price":1899,
  "category":["5G","paizhao"]
}

POST /goodsindex/_doc/4
{
  "name":"huawei shouji",
  "title":"huawei 5G youxi shouji",
  "price":3899,
  "category":["5G","youxi"]
}

POST /goodsindex/_doc/5
{
  "name":"xiaomi shouji",
  "title":"xiaomi 4G youxi shouji",
  "price":988,
  "category":["youxi","4G"]
}

POST /goodsindex/_doc/6
{
  "name":"xiaomi shouji",
  "title":"xiaomi 5G youxi qumianping shouji",
  "price":1899,
  "category":["youxi","5G","qumianping"]
}

POST /goodsindex/_doc/7
{
  "name":"xiaomi shouji",
  "title":"xiaomi 5G youxi shouji",
  "price":1299,
  "category":["youxi","5G"]
}

POST /goodsindex/_doc/8
{
  "name":"xiaomi shouji",
  "title":"xiaomi 4G shouji",
  "price":869,
  "category":["4G"]
}

POST /goodsindex/_doc/9
{
  "name":"huawei shouji",
  "title":"huawei 5G zhineng qumianping shouji",
  "price":2899,
  "category":["zhineng","5G","qumianping"]
}

POST /goodsindex/_doc/10
{
  "name":"youxi shouji",
  "title":"xiaomi 5G shouji",
  "price":2899,
  "category":["youxi","5G"]
}

1）SearchRequest搜索

• SearchRequest：是ES提供的一个专门用于搜索的对象；在创建SearchRequest对象时指定要操作的索引（默认情况下在所有索引中搜索），SearchRequest可以执行封装大部分的搜索；例如string search、queryDSL、query filter、phrase search、term query、query string、highlight search、聚合搜索等；

• SearchSourceBuilder：搜索源构建对象，在此对象中设置搜索的条件；最终将SearchSourceBuilder类设置到SearchRequest中，代表填充条件完毕；

• QueryBuilders：查询条件构建对象，用于构建不同类型的查询；

QueryBuilders更多用法：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-high-query-builders.html

• 示例代码：

package com.es.demo;

import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.sort.SortOrder;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.net.InetAddress;

/**
 * @author lscl
 * @version 1.0
 * @intro: Java操作ES  TransportClients的prepareSearch搜索
 * 官网相关案例:
 */
public class Demo06_Search_TransportClient_Prepare {
    // 创建Client连接对象
    private Settings settings;

    // es客户端对象
    private TransportClient client;

    @Before
    public void before() throws Exception {
        // 创建Client连接对象
        settings = Settings.builder().put("cluster.name", "elasticsearch").build();

        // 客户端对象
        client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
    }

    @After
    public void after() throws Exception {
        client.close();
    }

    // 抽取打印方法
    public void print(SearchResponse res) {
        System.out.println("查询到: " + res.getHits().getTotalHits().value);

        SearchHits hits = res.getHits();
        for (SearchHit hit : hits) {
            System.out.println("score: " + hit.getScore());
            // 文档的json返回形式
            System.out.println(hit.getSourceAsString());
            System.out.println("------------");
        }
    }

    // DSL query 
    @Test
    public void queryDSL() throws Exception {

        // 创建搜索条件对象
        SearchResponse res = client.prepareSearch("goodsindex")
                .setTypes("_doc")
                .setQuery(QueryBuilders.matchQuery("title", "xiaomi"))
                .get();

        print(res);
    }

    // query filter
    @Test
    public void queryFilter() throws Exception {

        SearchResponse res = client.prepareSearch("goodsindex")
                .setQuery(
                        QueryBuilders.boolQuery()
                                .must(QueryBuilders.matchQuery("title", "huawei"))
                                .mustNot(QueryBuilders.matchQuery("title", "youxi"))
                ).get();

        print(res);
    }

    // phrase search
    @Test
    public void phraseSearch() throws Exception {
        SearchResponse res = client.prepareSearch("goodsindex")
                .setQuery(QueryBuilders.matchPhraseQuery("title", "huawei 5G"))
                .get();

        print(res);
    }

    // term query
    @Test
    public void termQuery() throws Exception {

        SearchResponse res = client.prepareSearch("goodsindex")
                .setQuery(QueryBuilders.termQuery("title", "huawei 5G"))
                .get();

        print(res);
    }

    // string search
    @Test
    public void stringSearch() throws Exception {               // 带分词

        // 创建搜索条件对象
        SearchResponse res = client.prepareSearch("goodsindex")
                .setTypes("_doc")
                .setQuery(QueryBuilders.queryStringQuery("title:4G"))
                .setQuery(QueryBuilders.queryStringQuery("category:youxi"))
                .setQuery(QueryBuilders.queryStringQuery("price:[2000 TO 5000]"))
                .addSort("price", SortOrder.DESC)
                .setFrom(0)
                .setSize(3)
                .get();

        print(res);
    }

    // query string
    @Test
    public void queryString() throws Exception {

        SearchResponse res = client.prepareSearch("goodsindex")
                .setQuery(
                        // AND/OR 运算符查询
//                QueryBuilders.queryStringQuery("youxi 5G").field("name").field("title").defaultOperator(Operator.AND)

                        // 最少匹配词条
//                QueryBuilders.queryStringQuery("huawei youxi 4G").field("title").minimumShouldMatch("2")

                        // 模糊查询
//                QueryBuilders.queryStringQuery("huawkk~").field("title")

                        // 范围查询
                        QueryBuilders.queryStringQuery("[2000 TO 3000]").field("price")
                )
                .get();
        print(res);
    }

    // ids query
    @Test
    public void testIdQuery() throws Exception {

        SearchResponse res = client.prepareSearch("goodsindex")
                .setTypes("article")
                //设置要查询的id
                .setQuery(QueryBuilders.idsQuery().addIds("1", "2"))
                //执行查询
                .get();

        print(res);
    }
}

2）TransportClient搜索

使用TransportClient类提供的prepareSearch方法进行搜索，同样使用QueryBuilders进行搜索条件的构建，只是写法不同而已；

• 代码示例：

package com.es.demo;

import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.sort.SortOrder;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.net.InetAddress;

/**
 * @author lscl
 * @version 1.0
 * @intro: Java操作ES
 * 官网相关案例:
 */
public class Demo07_Search_TransportClient {
    // 创建Client连接对象
    private Settings settings;

    // es客户端对象
    private TransportClient client;

    // 抽取打印方法
    public void print(SearchResponse res) {
        System.out.println("查询到: " + res.getHits().getTotalHits().value);

        SearchHits hits = res.getHits();
        for (SearchHit hit : hits) {
            System.out.println("score: " + hit.getScore());
            // 文档的json返回形式
            System.out.println(hit.getSourceAsString());
            System.out.println("------------");
        }
    }

    @Before
    public void before() throws Exception {
        // 创建Client连接对象
        settings = Settings.builder().put("cluster.name", "my-cluster").build();

        // 客户端对象
        client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
        System.out.println(client.getClass());
    }

    @After
    public void after() throws Exception {
        client.close();
    }


    // query string
    @Test
    public void stringSearch() throws Exception {               // 带分词

        // 创建搜索对象
        SearchRequest searchRequest = new SearchRequest("goodsindex");

        // 创建查询构建对象
        SearchSourceBuilder builder = new SearchSourceBuilder();

        // 设置查询条件
        builder.query(QueryBuilders.queryStringQuery("title:shou*"));
        builder.query(QueryBuilders.queryStringQuery("category:youxi"));
        builder.query(QueryBuilders.queryStringQuery("price:[2000 TO 5000]"));
        builder.sort("price", SortOrder.DESC);
        builder.from(0);
        builder.size(2);

        // 封装查询
        searchRequest.source(builder);

        // 执行查询获取结果集
        SearchResponse res = client.search(searchRequest).get();

        System.out.println("查询到: " + res.getHits().getTotalHits().value);

        SearchHits hits = res.getHits();
        for (SearchHit hit : hits) {
            System.out.println("score: " + hit.getScore());
            // 文档的json返回形式
            System.out.println(hit.getSourceAsString());
            System.out.println("------------");
        }

    }

    // DSL query
    @Test
    public void queryDSL() throws Exception {

        // 创建搜索请求对象
        SearchRequest searchRequest = new SearchRequest("goodsindex");

        // 创建查询构建对象
        SearchSourceBuilder builder = new SearchSourceBuilder();

        // 设置查询条件
//        builder.query(QueryBuilders.matchAllQuery());
        builder.query(QueryBuilders.matchQuery("title", "xiaomi"));

        // 封装查询
        searchRequest.source(builder);

        // 执行查询获取结果集
        SearchResponse res = client.search(searchRequest).get();

        // 打印结果集
        print(res);
    }

    // query filter
    @Test
    public void queryFilter() throws Exception {
        SearchRequest searchRequest = new SearchRequest("goodsindex");

        // 创建查询构建对象
        SearchSourceBuilder builder = new SearchSourceBuilder();

        // 构建查询条件
        builder.query(
                QueryBuilders.boolQuery().
                        must(QueryBuilders.matchQuery("title", "huawei")).
                        mustNot(QueryBuilders.matchQuery("title", "youxi"))
        );

        // 封装查询条件
        searchRequest.source(builder);
        SearchResponse res = client.search(searchRequest).get();

        print(res);
    }

    // phrase query
    @Test
    public void phraseSearch() throws Exception {

        // 创建搜索请求对象
        SearchRequest searchRequest = new SearchRequest("goodsindex");

        // 创建查询构建对象
        SearchSourceBuilder builder = new SearchSourceBuilder();

        // 设置查询条件
        builder.query(QueryBuilders.matchPhraseQuery("title", "huawei 5G"));

        // 封装查询
        searchRequest.source(builder);

        // 执行查询获取结果集
        SearchResponse res = client.search(searchRequest).get();

        // 打印结果集
        print(res);
    }

    // term query
    @Test
    public void termQuery() throws Exception {

        // 创建搜索请求对象
        SearchRequest searchRequest = new SearchRequest("goodsindex");

        // 创建查询构建对象
        SearchSourceBuilder builder = new SearchSourceBuilder();

        // 设置查询条件
        builder.query(QueryBuilders.termQuery("title", "huawei 5G"));

        // 封装查询
        searchRequest.source(builder);

        // 执行查询获取结果集
        SearchResponse res = client.search(searchRequest).get();

        // 打印结果集
        print(res);
    }

    // query string
    @Test
    public void queryString() throws Exception {

        // 创建搜索请求对象
        SearchRequest searchRequest = new SearchRequest("goodsindex");

        // 创建查询构建对象
        SearchSourceBuilder builder = new SearchSourceBuilder();

        // 设置查询条件
        builder.query(
                // AND/OR 运算符查询
//                QueryBuilders.queryStringQuery("youxi 5G").field("name").field("title").defaultOperator(Operator.AND)

                // 最少匹配词条
//                QueryBuilders.queryStringQuery("huawei youxi 4G").field("title").minimumShouldMatch("2")

                // 模糊查询
//                QueryBuilders.queryStringQuery("huawkk~").field("title")

                // 范围查询
                QueryBuilders.queryStringQuery("[2000 TO 3000]").field("price")
        );

        // 封装查询
        searchRequest.source(builder);

        // 执行查询获取结果集
        SearchResponse res = client.search(searchRequest).get();

        // 打印结果集
        print(res);
    }

}

1.2.4 高亮搜索

Java在实现ES的高亮搜索主要就在于一个类：HighlightBuilder。该类封装了高亮搜索的条件，如高亮字段/高亮前后缀等；

HighlightBuilder具体用法：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/java-rest-high-search.html

package com.es.demo;

import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightField;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

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

/**
 * @author lscl
 * @version 1.0
 * @intro: 使用TransportClient进行高亮搜索
 */
public class Demo08_Highlight_Search_TransportClient {
    // 创建Client连接对象
    private Settings settings;

    // es客户端对象
    private TransportClient client;

    // 抽取打印方法
    public void print(SearchResponse res) {
        System.out.println("查询到: " + res.getHits().getTotalHits().value);

        SearchHits hits = res.getHits();
        for (SearchHit hit : hits) {
            System.out.println("score: " + hit.getScore());
            // 文档的json返回形式
            System.out.println(hit.getSourceAsString());
            System.out.println("------------");
        }
    }

    @Before
    public void before() throws Exception {
        // 创建Client连接对象
        settings = Settings.builder().put("cluster.name", "elasticsearch").build();

        // 客户端对象
        client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
    }

    @After
    public void after() throws Exception {
        client.close();
    }

    // 使用SearchRequest对象进行高亮搜索
    @Test
    public void searchQueryHighQuery() throws Exception {

        // 准备一个SearchRequest对象
        SearchRequest searchRequest = new SearchRequest("goodsindex");

        // 搜索条件构建对象
        SearchSourceBuilder builder = new SearchSourceBuilder();

        // 设置搜索条件
        builder.query(QueryBuilders.queryStringQuery("title:4G"));

        // 高亮构建对象
        HighlightBuilder highBuilder = new HighlightBuilder().field("title").preTags("<font color='red'>").postTags("</font>");

        // 设置高亮
        builder.highlighter(highBuilder);

        // 设置查询源
        searchRequest.source(builder);

        // 执行查询
        SearchResponse res = client.search(searchRequest).get();

        // 获取命中的记录
        SearchHits results = res.getHits();

        for (SearchHit result : results) {

            // 原始数据
            String sourceAsString = result.getSourceAsString();
            System.out.println(sourceAsString);

            // 高亮数据
            Map<String, HighlightField> high = result.getHighlightFields();
            System.out.println(high.get("title").fragments()[0].string());
            System.out.println("----------------");
        }
    }

    // 使用prepareSearch进行查询
    @Test
    public void transportClientHighQuery() throws Exception {

        // 高亮条件构造器
        HighlightBuilder highBuilder = new HighlightBuilder().field("title").preTags("</font style='red'>").postTags("</font>");

        // 创建搜索条件对象
        SearchResponse res = client.prepareSearch("goodsindex")
                .setTypes("_doc")
                .setQuery(QueryBuilders.queryStringQuery("title:4G"))
                .highlighter(highBuilder)               // 设置高亮数据
                .get();

        // 获取命中的记录
        SearchHits results = res.getHits();

        for (SearchHit result : results) {

            // 原始数据
            String sourceAsString = result.getSourceAsString();
            System.out.println(sourceAsString);

            // 高亮数据
            Map<String, HighlightField> high = result.getHighlightFields();
            System.out.println(high.get("title").fragments()[0].string());
            System.out.println("----------------");
        }
    }
}

1.2.5 聚合搜索

• 示例代码：

package com.es.demo;

import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.TransportAddress;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.aggregations.Aggregations;
import org.elasticsearch.search.aggregations.bucket.terms.Terms;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.transport.client.PreBuiltTransportClient;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.net.InetAddress;
import java.util.List;

/**
 * @author lscl
 * @version 1.0
 * @intro: 使用TransportClient进行聚合搜索
 */
public class Demo09_Aggs_TransportClient {

    // 创建Client连接对象
    private Settings settings;

    // es客户端对象
    private TransportClient client;

    // 抽取打印方法
    public void print(SearchResponse res) {
        System.out.println("查询到: " + res.getHits().getTotalHits().value);

        SearchHits hits = res.getHits();
        for (SearchHit hit : hits) {
            System.out.println("score: " + hit.getScore());
            // 文档的json返回形式
            System.out.println(hit.getSourceAsString());
            System.out.println("------------");
        }
    }

    @Before
    public void before() throws Exception {
        // 创建Client连接对象
        settings = Settings.builder().put("cluster.name", "my-cluster").build();

        // 客户端对象
        client = new PreBuiltTransportClient(settings)
                .addTransportAddress(new TransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
    }

    @After
    public void after() throws Exception {
        client.close();
    }

    // 计算每个分类下的商品数量(使用SearchRequest进行搜索)
    @Test
    public void aggs_searchRequest() throws Exception {
        // 创建搜索对象
        SearchRequest searchRequest = new SearchRequest("goodsindex");

        // 条件构建对象
        SearchSourceBuilder searchBuilder =
                new SearchSourceBuilder().aggregation(AggregationBuilders.terms("group_by_category").field("category"));

        // 设置搜索条件
        searchRequest.source(searchBuilder);

        // 执行搜索
        SearchResponse res = client.search(searchRequest).get();

        // 获取聚合数据
        Aggregations aggregations = res.getAggregations();

        // 根据分组的名称获取对应的值
        Terms group_by_category = aggregations.get("group_by_category");

        // 获取
        List<? extends Terms.Bucket> buckets = group_by_category.getBuckets();
        for (Terms.Bucket bucket : buckets) {

            // key
            String key = bucket.getKeyAsString();
            System.out.println("key:" + key);

            // docCount
            long docCount = bucket.getDocCount();
            System.out.println("docCount:" + docCount);

            System.out.println("--------------------");
        }

    }

    // 计算每个分类下的商品数量(使用prepareSearch进行搜索)
    @Test
    public void aggs_transportClientSearch() throws Exception {

        /*
        GET goodsindex/_doc/_search
        {
          "size": 0,
          "aggs": {
            "group_by_category": {
              "terms": {
                "field": "category"
              }
            }
          }
        }
         */
        SearchResponse res = client.prepareSearch("goodsindex")
                .setQuery(QueryBuilders.matchAllQuery())
                .addAggregation(AggregationBuilders.terms("group_by_category").field("category"))
                .setSize(0)         // 不要原始数据(只要聚合数据)
                .get();

        // 获取聚合数据
        Aggregations aggregations = res.getAggregations();

        // 根据分组的名称获取对应的值
        Terms group_by_category = aggregations.get("group_by_category");

        // 获取
        List<? extends Terms.Bucket> buckets = group_by_category.getBuckets();
        for (Terms.Bucket bucket : buckets) {

            // key
            String key = bucket.getKeyAsString();
            System.out.println("key:" + key);

            // docCount
            long docCount = bucket.getDocCount();
            System.out.println("docCount:" + docCount);

            System.out.println("--------------------");
        }
    }

}

1.3 Low Level REST Client

Low Level REST Client：ElasticSearch官方的低级客户端。之所以称为低级客户端，是因为它几乎没有帮助 Java 用户构建请求或解析响应。它只处理请求的路径和查询字符串构造；请求响应后，只是将响应的数据直接响应给客户端，并没有做其他处理；

官方文档：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/index.html

Low Level REST Client中相关的类：

• RestClient：用于发送一次HTTP请求到ElasticSearch服务器

• Request：用于封装一次HTTP请求，如请求方式/请求地址/请求体等

• Response：RestClient执行完请求后得到的响应；

• 示例代码：

package com.es.demo;

import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.HttpHost;
import org.apache.http.StatusLine;
import org.apache.http.entity.ContentType;
import org.apache.http.nio.entity.NStringEntity;
import org.apache.http.util.EntityUtils;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.Request;
import org.elasticsearch.client.Response;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.util.Arrays;

/**
 * @author lscl
 * @version 1.0
 * @intro:
 */
public class Demo10_RestClient {

    // 创建Client连接对象
    private RestClient restClient;

    // 抽取打印方法
    public void print(SearchResponse res) {
        System.out.println("查询到: " + res.getHits().getTotalHits().value);

        SearchHits hits = res.getHits();
        for (SearchHit hit : hits) {
            System.out.println("score: " + hit.getScore());
            // 文档的json返回形式
            System.out.println(hit.getSourceAsString());
            System.out.println("------------");
        }
    }

    @Before
    public void before() throws Exception {
        // 创建Client连接对象
        restClient = RestClient.builder(
                new HttpHost("localhost", 9200, "http")
        ).build();

    }

    @After
    public void after() throws Exception {
        restClient.close();
    }

    // 发送GET请求
    @Test
    public void test1() throws Exception {
        Request request = new Request(
                "GET",
                "/");

        Response response = restClient.performRequest(request);

        // 响应体
        HttpEntity entity = response.getEntity();
        System.out.println("entity: " + entity);
        System.out.println(EntityUtils.toString(entity));
        System.out.println("-----------------");

        // 响应头
        Header[] headers = response.getHeaders();
        System.out.println("headers: " + Arrays.toString(headers));
        System.out.println("-----------------");

        // 响应行
        StatusLine statusLine = response.getStatusLine();
        System.out.println("statusLine: " + statusLine);
        System.out.println("-----------------");

    }

    // get请求
    @Test
    public void test2() throws Exception {
        Request request = new Request(
                "GET",
                "/goodsindex/_doc/_search");

        Response response = restClient.performRequest(request);

        // 响应体
        HttpEntity entity = response.getEntity();
        System.out.println(EntityUtils.toString(entity));       // 将响应体以Json方式响应
    }

    // get请求
    @Test
    public void test3() throws Exception {

        /*
            GET goodsindex/_doc/_search
            {
              "query": {
                "match": {
                  "title": "5g"
                }
              }
            }
         */
        Request request = new Request(
                "GET",
                "/goodsindex/_doc/_search");

        // 准备Json请求体字符串
        String requestEntityJson = "{\n" +
                "              \"query\": {\n" +
                "                \"match\": {\n" +
                "                  \"title\": \"5g\"\n" +
                "                }\n" +
                "              }\n" +
                "            }";

        // 封装成HttpEntity请求体对象
        HttpEntity httpEntity = new NStringEntity(requestEntityJson, ContentType.APPLICATION_JSON);

        // 将请求体设置到本次请求上
        request.setEntity(httpEntity);

        // 执行请求获取结果集
        Response response = restClient.performRequest(request);

        // 响应体
        HttpEntity responseEntity = response.getEntity();
        System.out.println(EntityUtils.toString(responseEntity));       // 将响应体以Json方式响应
    }

    // get请求
    @Test
    public void test4() throws Exception {

        /*
            GET goodsindex/_doc/_search
            {
              "query": {
                "match": {
                  "title": "shouji"
                }
              },
              "sort": [
                {
                  "price": {
                    "order": "desc"
                  }
                }
              ]
            }
         */
        Request request = new Request(
                "GET",
                "/goodsindex/_doc/_search");

        // 准备Json请求体字符串
        String requestEntityJson = "{\n" +
                "          \"query\": {\n" +
                "            \"match\": {\n" +
                "              \"title\": \"shouji\"\n" +
                "            }\n" +
                "          },\n" +
                "          \"sort\": [\n" +
                "            {\n" +
                "              \"price\": {\n" +
                "                \"order\": \"desc\"\n" +
                "              }\n" +
                "            }\n" +
                "          ]\n" +
                "        }";


        // 将请求体设置到本次请求上
        request.setJsonEntity(requestEntityJson);

        // 执行请求获取结果集
        Response response = restClient.performRequest(request);

        // 响应体
        HttpEntity responseEntity = response.getEntity();
        System.out.println(EntityUtils.toString(responseEntity));       // 将响应体以Json方式响应
    }

    // post请求
    @Test
    public void test5() throws Exception {

        /*
            POST /goodsindex/_doc/100
            {
              "name":"meizu shouji",
              "title":"meizu 4G gaoqing youxi shouji",
              "price":1899,
              "category":["youxi","4G","gaoqing"]
            }
         */
        Request request = new Request(
                "POST",
                "/goodsindex/_doc/100");

        // 准备Json请求体字符串
        String requestEntityJson = "{\n" +
                "          \"name\":\"meizu shouji\",\n" +
                "          \"title\":\"meizu 4G gaoqing youxi shouji\",\n" +
                "          \"price\":1899,\n" +
                "          \"category\":[\"youxi\",\"4G\",\"gaoqing\"]\n" +
                "        }";


        // 将请求体设置到本次请求上
        request.setJsonEntity(requestEntityJson);

        // 格式化响应结果集
        request.addParameter("pretty", "true");

        // 执行请求获取结果集
        Response response = restClient.performRequest(request);

        // 响应体
        HttpEntity responseEntity = response.getEntity();
        System.out.println(EntityUtils.toString(responseEntity));       // 将响应体以Json方式响应
    }

    // put请求
    @Test
    public void test6() throws Exception {

        /*
            PUT /goodsindex/_doc/100
            {
              "name":"meizu shouji",
              "title":"meizu 5G paizhao shouji",
              "price":2899,
              "category":["paizhao","5G","gaoqing"]
            }
         */
        Request request = new Request(
                "PUT",
                "/goodsindex/_doc/100");

        // 准备Json请求体字符串
        String requestEntityJson = "{\n" +
                "              \"name\":\"meizu shouji\",\n" +
                "              \"title\":\"meizu 5G paizhao shouji\",\n" +
                "              \"price\":2899,\n" +
                "              \"category\":[\"paizhao\",\"5G\",\"gaoqing\"]\n" +
                "            }";


        // 将请求体设置到本次请求上
        request.setJsonEntity(requestEntityJson);

        // 格式化响应结果集
        request.addParameter("pretty", "true");

        // 执行请求获取结果集
        Response response = restClient.performRequest(request);

        // 响应体
        HttpEntity responseEntity = response.getEntity();
        System.out.println(EntityUtils.toString(responseEntity));       // 将响应体以Json方式响应
    }


    // delete请求
    @Test
    public void test7() throws Exception {

        /*
            DELETE /goodsindex/_doc/100
         */
        Request request = new Request(
                "DELETE",
                "/goodsindex/_doc/100");

        // 格式化响应结果集
        request.addParameter("pretty", "true");

        // 执行请求获取结果集
        Response response = restClient.performRequest(request);

        // 响应体
        HttpEntity responseEntity = response.getEntity();
        System.out.println(EntityUtils.toString(responseEntity));       // 将响应体以Json方式响应
    }

}

1.4 High Level REST Client

Java 高级 REST 客户端在 Java 低级 REST 客户端之上运行。它的主要目标是公开 API 特定的方法，接受请求对象作为参数并返回响应对象，以便请求编组和响应解组由客户端本身处理。要求Elasticsearch版本为2.0或者更高。

官方文档：https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.6/index.html

• High Level REST Client中相关的类：High Level REST Client和TransportClient一样支持IndexRequest，DeleteRequest，UpdateRequest，GetRequest，SearchRequest，因此用法和我们之前使用TransportClient类似；

• 示例代码：

package com.es.demo;

import com.es.entity.Goods;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.http.HttpHost;
import org.elasticsearch.action.delete.DeleteRequest;
import org.elasticsearch.action.get.GetRequest;
import org.elasticsearch.action.get.GetResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.action.update.UpdateRequest;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

/**
 * @author lscl
 * @version 1.0
 * @intro: RestHighLevelClient 用法
 */
public class Demo11_RestHighLevelClient {
    // 高级查询对象
    private RestHighLevelClient client;

    // 抽取打印方法
    public void print(SearchResponse res) {
        System.out.println("查询到: " + res.getHits().getTotalHits().value);

        SearchHits hits = res.getHits();
        for (SearchHit hit : hits) {
            System.out.println("score: " + hit.getScore());
            // 文档的json返回形式
            System.out.println(hit.getSourceAsString());
            System.out.println("------------");
        }
    }

    @Before
    public void before() throws Exception {
        //获取连接客户端
        client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("localhost", 9200, "http")
                )
        );
    }

    @After
    public void after() throws Exception {
        client.close();
    }

    @Test
    public void insert() throws Exception {         // 增
        // 准备数据
        Goods goods = new Goods("11",
                "meizu shouji", "meizu 5G zhineng paizhao shouji",
                2899.0D, new String[]{"5G", "zhineng", "paizhao"}
        );

        // 转换为json
        String goodsJson = new ObjectMapper().writeValueAsString(goods);

        // 准备索引请求对象
        IndexRequest indexRequest = new IndexRequest("goodsindex", "_doc", "11");

        // 设置数据源
        indexRequest.source(goodsJson, XContentType.JSON);

        client.index(indexRequest, RequestOptions.DEFAULT);
    }


    @Test
    public void delete() throws Exception {         // 删

        DeleteRequest deleteRequest = new DeleteRequest("goodsindex", "_doc", "1");

        client.delete(deleteRequest, RequestOptions.DEFAULT);
    }


    @Test
    public void update() throws Exception {         // 改

        UpdateRequest updateRequest = new UpdateRequest("goodsindex", "_doc", "2");

        // 准备数据
        Goods goods = new Goods("2",
                "zhongxing shouji", "zhongxing 4G youxi shouji",
                2899.0D, new String[]{"4G", "youxi"});

        String goodsJson = new ObjectMapper().writeValueAsString(goods);

        updateRequest.doc(goodsJson, XContentType.JSON);

        client.update(updateRequest, RequestOptions.DEFAULT);
    }


    @Test
    public void query() throws Exception {          // 查

        GetRequest getRequest = new GetRequest("goodsindex", "_doc", "2");

        GetResponse res = client.get(getRequest, RequestOptions.DEFAULT);

        System.out.println(res.getSourceAsString());
    }

    @Test
    public void searchRequest() throws Exception {      // searchRequest查询

        SearchRequest searchRequest = new SearchRequest("goodsindex");

        SearchSourceBuilder builder = new SearchSourceBuilder()
                .query(QueryBuilders.queryStringQuery("title:meizu"));

        searchRequest.source(builder);

        SearchResponse res = client.search(searchRequest, RequestOptions.DEFAULT);

        print(res);
    }
}

1.5 SQL搜索ElasticSearch

1）开启ES白金版功能

• 1）

• 2）

• 3）：

• 4）：

2）示例代码

• 引入相关依赖：

<!--配置ES的SQL支持 maven仓库-->
<repositories>
    <repository>
        <id>elastic.co</id>
        <url>https://artifacts.elastic.co/maven</url>
    </repository>
</repositories>

<dependencies>
    <dependency>
        <groupId>org.elasticsearch.plugin</groupId>
        <artifactId>x-pack-sql-jdbc</artifactId>
        <version>7.6.2</version>
    </dependency>
</dependencies>

• 示例代码：

package com.es.demo;

import org.junit.Test;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

/**
 * @author lscl
 * @version 1.0
 * @intro:
 */
public class Demo12_ES_JDBC {

    @Test
    public void test1() throws Exception {
        // 获取与ES服务器的连接
        Connection connection = DriverManager.getConnection("jdbc:es://http://localhost:9200");

        // 创建语句对象
        Statement statement = connection.createStatement();

        // 执行SQL,获取结果集
        ResultSet rs = statement.executeQuery("select * from goodsindex");

        while (rs.next()) {
            System.out.print("name: " + rs.getString("name")+"\t");
            System.out.print("title: " + rs.getString("title")+"\t");
            System.out.print("price: " + rs.getString("price")+"\t");
            System.out.print("category: " + rs.getString("category")+"\t");
            System.out.println();
        }

        connection.close();
    }
}

二、Spring Data ElasticSearch

Spring Data ElasticSearch是SpringData大家族的一员，Spring Data 的使命是给各种数据访问提供统一的编程接口，不管是关系型数据库（如MySQL），还是非关系数据库（如Redis），或者类似Elasticsearch这样的索引数据库。从而简化开发人员的代码，提高开发效率。

• SpringData官网：https://spring.io/projects/spring-data
• SpringDataElasticSearch官网：https://docs.spring.io/spring-data/elasticsearch/docs/4.0.3.RELEASE/reference/html/#preface

• 引入项目依赖：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.es</groupId>
    <artifactId>02_ElasticSearch_Template</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.1.RELEASE</version>
        <relativePath/>
    </parent>

    <!--锁定ES版本-->
    <properties>
        <elasticsearch.version>7.6.2</elasticsearch.version>
    </properties>

    <dependencies>
        <!--SpringBoot整合Elasticsearch-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
        </dependency>
        
        <!--SpringBoot整合测试单元-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        
        <!--lombok插件-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.12</version>
        </dependency>

    </dependencies>
</project>

2.1 Template 查询

SpringData家族为大部分产品都提供了查询模板类，例如JdbcTemplate、RedisTemplate、RabbitTempalte等简化我们的操作；同样，SpringDataElasticSearch提供了ElasticsearchRestTemplate类来简化Java操作ES的代码；

• SpringDataElasticSearch官网案例：https://docs.spring.io/spring-data/elasticsearch/docs/4.0.3.RELEASE/reference/html/#elasticsearch.operations

• 在SpringDataElasticSearch官网中提供有四种操作ES的相关类：
  • IndexOperations：有关于索引相关操作，如创建或删除索引。
  • DocumentOperations：有关于文档的操作，根据文档的id进行存储、更新和检索文档的操作。
  • SearchOperations：搜索文档相关操作
  • ElasticsearchOperations ：结合了DocumentOperations和SearchOperations接口。

Spring官网中提供有ElasticsearchTemplate与ElasticsearchRestTemplate 两个ES相关模板类，其中ElasticsearchTemplate是使用TransportClient对ElasticsearchOperations的实现；ElasticsearchRestTemplate 则是使用High Level REST Client对ElasticsearchOperations的实现；

Tips：ElasticsearchTemplate从4.0版本起不再使用，使用ElasticsearchRestTemplate代替。

• 定义实体类：

关于实体类定义的详细文档：https://docs.spring.io/spring-data/elasticsearch/docs/4.0.3.RELEASE/reference/html/#elasticsearch.mapping

package com.es.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.data.annotation.Id;
import org.springframework.data.elasticsearch.annotations.Document;
import org.springframework.data.elasticsearch.annotations.Field;
import org.springframework.data.elasticsearch.annotations.FieldType;

@Data
@AllArgsConstructor
@NoArgsConstructor
@Document(indexName = "goodsindex", type = "_doc", shards = 1, replicas = 2)
// ES7.0后不支持type功能(一个索引只能有一个type,名为_doc)
public class Goods {

    @Id
    private String id;

    @Field(index = true, store = false, fielddata = false, type = FieldType.Text, analyzer = "standard", searchAnalyzer = "standard")
    private String name;

    @Field(analyzer = "standard", searchAnalyzer = "standard")
    private String title;

    @Field
    private Double price;

    @Field
    private String[] category;
}