ElasticSearch使用RestHighLevelClient进行搜索查询
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 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
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;
} }
写一个service。
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);
} }
上面的ElasticSearchService 有几个常用的Builder类和方法需要了解下。
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](http://xbib.org/elasticsearch/2.1.1/apidocs/org/elasticsearch/index/query/BoolQueryBuilder.html#filter-org.elasticsearch.index.query.QueryBuilder-)([QueryBuilder](http://xbib.org/elasticsearch/2.1.1/apidocs/org/elasticsearch/index/query/QueryBuilder.html) queryBuilder)
Adds a query that must appear in the matching documents but will not contribute to scoring.
[must](http://xbib.org/elasticsearch/2.1.1/apidocs/org/elasticsearch/index/query/BoolQueryBuilder.html#must-org.elasticsearch.index.query.QueryBuilder-)([QueryBuilder](http://xbib.org/elasticsearch/2.1.1/apidocs/org/elasticsearch/index/query/QueryBuilder.html) queryBuilder)
Adds a query that must appear in the matching documents and will contribute to scoring.
[should](http://xbib.org/elasticsearch/2.1.1/apidocs/org/elasticsearch/index/query/BoolQueryBuilder.html#should-org.elasticsearch.index.query.QueryBuilder-)([QueryBuilder](http://xbib.org/elasticsearch/2.1.1/apidocs/org/elasticsearch/index/query/QueryBuilder.html) 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
//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()));
}
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。
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);
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
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;
} }
首先在es中维护几条数据，如下：
postman测试一下，结果如下：
【end】
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