ElasticSearch使用RestHighLevelClient进行搜索查询

悠悠 2023-02-13 05:41 13阅读 0赞

Elasticsearch Java API有四类client连接方式：TransportClient、  RestClient 、Jest、 Spring\_Data\_Elasticsearch。其中TransportClient、  RestClient是Elasticsearch原生的api，TransportClient会在8.0版本中完成删除，替代的是HighLevelRestClient，它使用HTTP请求而不是Java序列化请求。Spring\_Data\_Elasticsearch是spring集成的Elasticsearch开发包。在博客园 [Elasticsearch 6.4基本操作 - Java版][Elasticsearch 6.4_ - Java] 一文中有简单的描述，不再过多引述。本文主要记录一下HighLevelRestClient在spingboot项目中的使用。

使用es主要是做一些非关系型数据文档的检索，公司用的最多的是配合kibana进行可视化的日志检索，非常方便。elasticsearch、kibana安装，配置和使用，有大量博客记录，此处不再说明。

@Configuration配置sping并启动容器 @Bean注册Bean

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import org.apache.http.HttpHost;
    import org.apache.http.client.config.RequestConfig.Builder;
    import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
    import org.elasticsearch.client.RestClient;
    import org.elasticsearch.client.RestClientBuilder;
    import org.elasticsearch.client.RestClientBuilder.HttpClientConfigCallback;
    import org.elasticsearch.client.RestClientBuilder.RequestConfigCallback;
    import org.elasticsearch.client.RestHighLevelClient;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
     
    import java.util.ArrayList;
     
    @Configuration
    public class ESConfig {
     
        private static String hosts = "127.0.0.1"; // 集群地址，多个用,隔开
        private static int port = 9200; // 使用的端口号
        private static String schema = "http"; // 使用的协议
        private static ArrayList<HttpHost> hostList = null;
     
        private static int connectTimeOut = 1000; // 连接超时时间
        private static int socketTimeOut = 30000; // 连接超时时间
        private static int connectionRequestTimeOut = 500; // 获取连接的超时时间
     
        private static int maxConnectNum = 100; // 最大连接数
        private static int maxConnectPerRoute = 100; // 最大路由连接数
        static {
            hostList = new ArrayList<>();
            String[] hostStrs = hosts.split(",");
            for (String host : hostStrs) {
                hostList.add(new HttpHost(host, port, schema));
            }
        }
        @Bean
        public RestHighLevelClient client(){
            RestClientBuilder builder = RestClient.builder(hostList.toArray(new HttpHost[0]));
            // 异步httpclient连接延时配置
            builder.setRequestConfigCallback(new RequestConfigCallback() {
                @Override
                public Builder customizeRequestConfig(Builder requestConfigBuilder) {
                    requestConfigBuilder.setConnectTimeout(connectTimeOut);
                    requestConfigBuilder.setSocketTimeout(socketTimeOut);
                    requestConfigBuilder.setConnectionRequestTimeout(connectionRequestTimeOut);
                    return requestConfigBuilder;
                }
            });
            // 异步httpclient连接数配置
            builder.setHttpClientConfigCallback(new HttpClientConfigCallback() {
                @Override
                public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
                    httpClientBuilder.setMaxConnTotal(maxConnectNum);
                    httpClientBuilder.setMaxConnPerRoute(maxConnectPerRoute);
                    return httpClientBuilder;
                }
            });
            RestHighLevelClient client = new RestHighLevelClient(builder);
            return client;
        }
    }

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

写一个service。

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import org.elasticsearch.action.search.SearchRequest;
    import org.elasticsearch.action.search.SearchResponse;
    import org.elasticsearch.client.RequestOptions;
    import org.elasticsearch.client.RestHighLevelClient;
    import org.elasticsearch.index.query.BoolQueryBuilder;
    import org.elasticsearch.index.query.MatchQueryBuilder;
    import org.elasticsearch.index.query.QueryBuilders;
    import org.elasticsearch.index.query.RangeQueryBuilder;
    import org.elasticsearch.search.SearchHit;
    import org.elasticsearch.search.SearchHits;
    import org.elasticsearch.search.builder.SearchSourceBuilder;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
     
    import java.io.IOException;
    import java.util.Arrays;
     
    @Service
    public class ElasticSearchService {
        private static final Logger log = LoggerFactory.getLogger(ElasticSearchService.class);
     
        @Autowired
        private RestHighLevelClient client;
     
        public String search() throws IOException {
            BoolQueryBuilder boolBuilder = QueryBuilders.boolQuery();
            SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
            MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("fields.entity_id", "319");//这里可以根据字段进行搜索，must表示符合条件的，相反的mustnot表示不符合条件的
           // RangeQueryBuilder rangeQueryBuilder = QueryBuilders.rangeQuery("fields_timestamp"); //新建range条件
           // rangeQueryBuilder.gte("2019-03-21T08:24:37.873Z"); //开始时间
           // rangeQueryBuilder.lte("2019-03-21T08:24:37.873Z"); //结束时间
           // boolBuilder.must(rangeQueryBuilder);
            boolBuilder.must(matchQueryBuilder);
            sourceBuilder.query(boolBuilder); //设置查询，可以是任何类型的QueryBuilder。
            sourceBuilder.from(0); //设置确定结果要从哪个索引开始搜索的from选项，默认为0
            sourceBuilder.size(100); //设置确定搜素命中返回数的size选项，默认为10
    　　　　  sourceBuilder.timeout(new TimeValue(60, TimeUnit.SECONDS)); //设置一个可选的超时，控制允许搜索的时间。
    
    
            sourceBuilder.fetchSource(new String[] {"fields.port","fields.entity_id","fields.message"}, new String[] {}); //第一个是获取字段，第二个是过滤的字段，默认获取全部
            SearchRequest searchRequest = new SearchRequest("customer"); //索引
            searchRequest.types("doc"); //类型
            searchRequest.source(sourceBuilder);
            SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);
            SearchHits hits = response.getHits();  //SearchHits提供有关所有匹配的全局信息，例如总命中数或最高分数：
            SearchHit[] searchHits = hits.getHits();
            for (SearchHit hit : searchHits) {
                log.info("search -> {}",hit.getSourceAsString());
            }
            return Arrays.toString(searchHits);
        }
    }

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

--------------------

上面的ElasticSearchService 有几个常用的Builder类和方法需要了解下。

[BoolQueryBuilder ][BoolQueryBuilder]用来拼装查询条件。一般来说must的性能要低一些，因为他要进行打分评估，也就是说要进行\_score，而filter则不会。

`filter(QueryBuilder queryBuilder)`

Adds a query that **must** appear in the matching documents but will not contribute to scoring.

`must(QueryBuilder queryBuilder)`

Adds a query that **must** appear in the matching documents and will contribute to scoring.

`should(QueryBuilder queryBuilder)`

Adds a query that *should* appear in the matching documents.

简单来说：must 相当于 与 & = ；must not 相当于 非 ~   ！=；should 相当于 或  |   or ；filter  过滤

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//filter 效率比 must高的多 
     if (StringUtils.isNotBlank(query.getRouterDatabaseNo())) {
    　　　boolQueryBuilder.filter(QueryBuilders.termQuery("routerDatabaseNo", query.getRouterDatabaseNo()));
     }
    
    //时间段 一定要有头有尾 不然会出现慢查询
     if (null != query.getCreateTime() && null != query.getUpdateTime()) {
         boolQueryBuilder.filter(QueryBuilders.rangeQuery("createTime").from( query.getCreateTime()).to(query.getUpdateTime()));
     }

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

[SearchSourceBuilder][]

SearchRequest searchRequest = new SearchRequest("customer"); //将请求限制为一个索引
     SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
     searchRequest.types("doc"); //将请求限制为一个类型。
     searchRequest.source(sourceBuilder); //将SearchSourceBuilder添加到SeachRequest

创建`SeachRequest`，没有参数，这将针对所有索引运行。有参数，则按参数所传值为索引，此处“customer”为索引值。大多数搜索参数都添加到`SearchSourceBuilder`中，它为搜索请求body中的所有内容提供了setter。

`SearchSourceBuilder的排序：`允许添加一个或多个`SortBuilder`实例，有四种特殊的实现（Field-，Score-，GeoDistance-和ScriptSortBuilder）。

sourceBuilder.sort(new ScoreSortBuilder().order(SortOrder.DESC)); //按_score降序排序（默认值）。
    sourceBuilder.sort(new FieldSortBuilder("_uid").order(SortOrder.ASC));//也可以按_id字段进行升序排序

SearchSourceBuilder的源过滤：默认情况下，搜索请求会返回文档`_source`的内容，但与Rest API中的内容一样，你可以覆盖此行为，例如，你可以完全关闭`_source`检索：

sourceBuilder.fetchSource(false);

该方法还接受一个或多个通配符模式的数组，以控制以更精细的方式包含或排除哪些字段：

String[] includeFields = new String[] {"title", "user", "innerObject.*"};
    String[] excludeFields = new String[] {"_type"};
    sourceBuilder.fetchSource(includeFields, excludeFields);

SearchSourceBuilder的请求结果高亮显示：通过在SearchSourceBuilder上设置HighlightBuilder，可以实现高亮搜索结果，通过将一个或多个HighlightBuilder.Field实例添加到HighlightBuilder，可以为每个字段定义不同的高亮行为。

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
    HighlightBuilder highlightBuilder = new HighlightBuilder(); //创建一个新的HighlightBuilder。
    HighlightBuilder.Field highlightTitle = new HighlightBuilder.Field("title");  //为title字段创建字段高光色。
    highlightTitle.highlighterType("unified"); // 设置字段高光色类型。
    highlightBuilder.field(highlightTitle);   //将字段高光色添加到高亮构建器。
    HighlightBuilder.Field highlightUser = new HighlightBuilder.Field("user");
    highlightBuilder.field(highlightUser);
    searchSourceBuilder.highlighter(highlightBuilder);

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

[SearchSourceBuilder][] 更多api可以参考链接文章，归纳的很详细了，不再过多引述。

--------------------

写一个controller用于测试

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import java.io.IOException;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import com.slowcity.admin.service.ElasticSearchService;
    
    @RestController 
    @RequestMapping("/test")
    public class TestResource {
        
        @Autowired
        private ElasticSearchService elasticSearchService;
        private static final Logger log = LoggerFactory.getLogger(TestResource.class);
        //条件 查询 
        @PostMapping("/v1/test")
        public String query( ) {
            String queryResult =null;
            try {
                queryResult = elasticSearchService.search();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return queryResult;
        }
    }

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

首先在es中维护几条数据，如下：

postman测试一下，结果如下：

![format_png][]

[实现分布式定时任务调度][Link 1]  
[» ][Link 2]下一篇： [可实现的全局唯一有序ID生成策略][Link 2]

**相关博文：**  
· [Elasticsearch搜索查询语法][Elasticsearch]  
· [elasticsearch查询][elasticsearch]  
· [elasticsearch的rest搜索--- 查询][elasticsearch_rest_---]  
· [RestHighLevelClient查询es][RestHighLevelClient_es]  
· [ElasticSearchRestHighLevelClient通用操作][ElasticSearchRestHighLevelClient]  
» [更多推荐...][...]

[Elasticsearch 6.4_ - Java]: https://www.cnblogs.com/swordfall/p/9981883.html
[aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg
[BoolQueryBuilder]: http://xbib.org/elasticsearch/2.1.1/apidocs/org/elasticsearch/index/query/BoolQueryBuilder.html
[SearchSourceBuilder]: https://segmentfault.com/a/1190000016830796?utm_source=tag-newest
[format_png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9pbWcyMDE4LmNuYmxvZ3MuY29tL2Jsb2cvMTE2MDc0OC8yMDE5MTAvMTE2MDc0OC0yMDE5MTAyNDE3MTI0MzkyNi01MzkzMjU0Mi5wbmc?x-oss-process=image/format,png
[Link 1]: https://www.cnblogs.com/slowcity/p/11671231.html
[Link 2]: https://www.cnblogs.com/slowcity/p/11737314.html
[Elasticsearch]: https://www.cnblogs.com/haixiang/p/12095578.html
[elasticsearch]: https://www.cnblogs.com/lyq-biu/p/9867150.html
[elasticsearch_rest_---]: https://www.cnblogs.com/ykkBlog/p/4667857.html
[RestHighLevelClient_es]: https://www.cnblogs.com/wangrudong003/p/10959525.html
[ElasticSearchRestHighLevelClient]: https://www.cnblogs.com/WeidLang/p/10245659.html
[...]: https://recomm.cnblogs.com/blogpost/11727579