二.springBoot项目集成ElasticSearch及使用

1.依赖引入

<!--elasticsearch搜索引擎-->
<!--高版本7.0后TransportClient已被淘汰，用rest-high-level-client代替-->
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-high-level-client</artifactId>
    <version>7.6.2</version>
</dependency>
<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>7.6.2</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>elasticsearch-rest-client</artifactId>
    <version>7.6.2</version>
    <scope>compile</scope>
</dependency>

2.ElasticSearch常见用法

package com.lmy.elasticSearchTest;


import cn.hutool.core.bean.BeanUtil;
import com.alibaba.fastjson.JSON;
import com.lmy.elasticSearchTest.pojo.User;
import org.apache.http.HttpHost;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
import org.elasticsearch.action.admin.indices.create.CreateIndexRequest;
import org.elasticsearch.action.admin.indices.create.CreateIndexResponse;
import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
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.action.support.master.AcknowledgedResponse;
import org.elasticsearch.action.update.UpdateRequest;
import org.elasticsearch.action.update.UpdateResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.indices.GetIndexRequest;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.*;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.junit.Before;
import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;

/**
 * es 7.6.x API测试
 */
public class ElasticSearchApiTest {

    private RestHighLevelClient restHighLevelClient;

    // 集群地址，多个用,隔开
    @Value("${es.hosts}")
    private String hosts = "127.0.0.1";
    // 使用的端口号
    @Value("${es.port}")
    private int port = 9200;
    @Value("${es.userName}")
    private String userName = "";
    @Value("${es.password}")
    private String password = "";

    // 使用的协议
    private static String schema = "http";

    // 连接超时时间
    private static int connectTimeOut = 1000;
    // 连接超时时间
    private static int socketTimeOut = 30000;
    // 获取连接的超时时间
    private static int connectionRequestTimeOut = 500;

    @Before
    public void init() throws IOException {
        /*// 单机模式
        restHighLevelClient = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost("127.0.0.1", 9200, "http")));*/

        // 集群模式
        /*用户认证对象*/
        final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        /*设置账号密码*/
        credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials(userName, password));

        RestClientBuilder builder = RestClient.builder(this.getHostList().toArray(new HttpHost[0]))
                .setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
                    @Override
                    public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpAsyncClientBuilder) {
                        return httpAsyncClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
                    }
                });
        // 异步httpclient连接延时配置
        builder.setRequestConfigCallback(new RestClientBuilder.RequestConfigCallback() {
            @Override
            public RequestConfig.Builder customizeRequestConfig(RequestConfig.Builder requestConfigBuilder) {
                requestConfigBuilder.setConnectTimeout(connectTimeOut);
                requestConfigBuilder.setSocketTimeout(socketTimeOut);
                requestConfigBuilder.setConnectionRequestTimeout(connectionRequestTimeOut);
                return requestConfigBuilder;
            }
        });
        restHighLevelClient = new RestHighLevelClient(builder);

    }

    public ArrayList<HttpHost> getHostList() {
        ArrayList<HttpHost> hostList = new ArrayList<>();
        String[] hostStrs = hosts.split(",");
        for (String host : hostStrs) {
            hostList.add(new HttpHost(host, port, schema));
        }
        return hostList;
    }

    /**
     * 索引操作
     * @throws IOException
     */

    // 测试索引的创建 Request
    @Test
    public void testCreateIndex() throws IOException {
        // 创建索引的请求
        CreateIndexRequest request = new CreateIndexRequest("api_test");
        //
        CreateIndexResponse response = restHighLevelClient.indices().create(request, RequestOptions.DEFAULT);
        System.out.println(response);
        restHighLevelClient.close();
    }

    // 测试索引是否存在
    @Test
    public void testIndexIsExists() throws IOException {
        GetIndexRequest request = new GetIndexRequest("api_test");
        boolean exists = restHighLevelClient.indices().exists(request, RequestOptions.DEFAULT);
        System.out.println(exists);
        restHighLevelClient.close();
    }

    // 测试索引删除
    @Test
    public void testDeleteIndex() throws IOException {
        DeleteIndexRequest request = new DeleteIndexRequest("blog");
        AcknowledgedResponse response = restHighLevelClient.indices().delete(request, RequestOptions.DEFAULT);
        //查看索引是否存在
        System.out.println(response.isAcknowledged());
        restHighLevelClient.close();
    }

    /**
     * 文档操作
     */

    // 测试添加文档
    @Test
    public void testAddDocument() throws IOException {
        // 创建一个User对象
        User user = new User("wangmazi", 99);
        // 创建请求
        IndexRequest request = new IndexRequest("api_test");
        // 制定规则 PUT /api_test/_doc/1
        request.id("3");//设置文档id
        request.timeout(TimeValue.timeValueMillis(1000));//设置超时时间
        request.source(JSON.toJSONString(user), XContentType.JSON);//设置添加的文档内容
        // 客户端发送请求，获取响应的结果
        IndexResponse response = restHighLevelClient.index(request, RequestOptions.DEFAULT);
        System.out.println(response);
        restHighLevelClient.close();
    }

    // 测试获得文档信息
    @Test
    public void testGetDocument() throws IOException {
        GetRequest request = new GetRequest("api_test","_all", "1");
        GetResponse response = restHighLevelClient.get(request, RequestOptions.DEFAULT);
        // 打印文档内容
        System.out.println(response.getSourceAsString());
        System.out.println(request);
        restHighLevelClient.close();
    }

    // 获取文档，判断是否存在 get /api_test/_doc/1
    @Test
    public void testDocumentIsExists() throws IOException {
        GetRequest request = new GetRequest("api_test","_all", "1");
        // 不获取返回的 _source的上下文了
        request.fetchSourceContext(new FetchSourceContext(false));
        request.storedFields("_none_");
        boolean exists = restHighLevelClient.exists(request, RequestOptions.DEFAULT);
        System.out.println(exists);
        restHighLevelClient.close();
    }

    // 测试更新文档内容
    @Test
    public void testUpdateDocument() throws IOException {
        UpdateRequest request = new UpdateRequest("api_test","_all", "1");
        User user = new User("lmy", 25);
        request.doc(JSON.toJSONString(user), XContentType.JSON);
        UpdateResponse update = restHighLevelClient.update(request, RequestOptions.DEFAULT);
        System.out.println(update.status());
        restHighLevelClient.close();
    }

    // 测试删除文档
    @Test
    public void testDeleteDocument() throws IOException {
        DeleteRequest request = new DeleteRequest("api_test","_all", "3");
        request.timeout("1s");
        DeleteResponse response = restHighLevelClient.delete(request, RequestOptions.DEFAULT);
        System.out.println(response.status());
        restHighLevelClient.close();
    }

    // 查询
    // SearchRequest 搜索请求
    // SearchSourceBuilder 条件构造
    // HighlightBuilder 高亮
    // TermQueryBuilder 精确查询
    // MatchAllQueryBuilder
    // xxxQueryBuilder ...
    /**
     * QueryBuilders:termQuery(精确查询)，matchQuery(匹配查询)，rangeQuery(范围查询)，multiMatchQuery(多个字段上进行匹配查询)，wildcardQuery(通配符查询，支持 * 和 ? 通配符)，existsQuery(检查文档中是否存在某个字段)，
     * BoolQueryBuilder:复合查询 must(AND)、should(OR)、must_not(NOT)、filter(过滤条件 必须满足 filter 子句中的所有条件)
     */
    @Test
    public void testSearch() throws IOException {
        List<User> userList = new ArrayList<>();
        // 1.创建查询请求对象 参数为索引名(库名)
        SearchRequest request = new SearchRequest("api_test");
        // 2.构建搜索条件
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        // (1)查询条件 使用QueryBuilders工具类创建
        // 精确查询
        TermQueryBuilder termQuery = QueryBuilders.termQuery("name", "lmy");
        // 匹配查询
        MatchAllQueryBuilder matchAllQuery = QueryBuilders.matchAllQuery();
        MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("name", "lmy");
        // 范围查询
        RangeQueryBuilder rangeQueryBuilder = QueryBuilders.rangeQuery("age");
        rangeQueryBuilder.gte("17");
        rangeQueryBuilder.lte("20");
        // 复合查询 must、should、must_not、filter
        BoolQueryBuilder boolQueryBuilder = new BoolQueryBuilder();
        boolQueryBuilder.must(QueryBuilders.matchQuery("name", "lmy"));
        boolQueryBuilder.must(QueryBuilders.rangeQuery("age").gte("17").lte("20"));
        // (2)其他<可有可无>：（可以参考 SearchSourceBuilder 的字段部分）
        // 设置高亮
        searchSourceBuilder.highlighter(new HighlightBuilder());
        // 分页
        searchSourceBuilder.from(0);
        searchSourceBuilder.size(3);
        searchSourceBuilder.timeout(new TimeValue(60, TimeUnit.SECONDS));
        // (3)条件投入
        searchSourceBuilder.query(boolQueryBuilder);
        // 3.添加条件到请求
        request.source(searchSourceBuilder);
        // 4.客户端查询请求
        SearchResponse response = restHighLevelClient.search(request, RequestOptions.DEFAULT);
        // 5.查看返回结果
        SearchHits hits = response.getHits();
        System.out.println(JSON.toJSONString(hits));
        System.out.println("========================");
        for (SearchHit h:hits.getHits()) {
            System.out.println(h.getSourceAsMap());
            User user = BeanUtil.mapToBean(h.getSourceAsMap(), User.class,true);
            userList.add(user);
        }
        System.out.println(userList);
        restHighLevelClient.close();
    }

    // 特殊的，真的项目一般会 批量插入数据
    @Test
    public void testBulk() throws IOException {
        BulkRequest request = new BulkRequest();
        request.timeout("10s");

        ArrayList<User> list = new ArrayList<>();
        list.add(new User("lmy-1",18));
        list.add(new User("lmy-2",19));
        list.add(new User("lmy-3",20));
        list.add(new User("lmy-4",21));

        // 批量请求处理
        for (User u :list) {
            request.add(
              new IndexRequest("api_test").source(JSON.toJSONString(u),XContentType.JSON)
            );
        }
        BulkResponse bulk = restHighLevelClient.bulk(request, RequestOptions.DEFAULT);
        System.out.println(bulk.status());
        restHighLevelClient.close();
    }
}