获取数量count

在ES查询时，SearchResponse中的SearchHits中包含有满足条件的记录数量；为了减少数据量的传递，查询时需要设定size为0，避免返回记录的详细信息，浪费时间与流量。

public long count(List
   
     lstIndex, QueryBuilder queryBuilder) {
       try (RestHighLevelClient client = getClient()) {
           SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();        sourceBuilder.query(queryBuilder);        //  sourceBuilder.from(0);        sourceBuilder.size(0);        sourceBuilder.timeout(new TimeValue(60, TimeUnit.SECONDS));        SearchRequest reqSearch = new SearchRequest(lstIndex.toArray(new String[0]));        reqSearch.source(sourceBuilder);        SearchResponse respSearch = client.search(reqSearch);        SearchHits hitsSearch = respSearch.getHits();        return hitsSearch.getTotalHits();    } catch (ElasticsearchStatusException ex) {
           _logger.error("Count fail: {}", ex);    }}

判断Index是否存在

ES7与ES6下判断的方式是不同的。

ES7中判断Index

在ES7下，可以方便地通过客户端连接的indices().exists来判断：

static boolean isIndexExists(String strIndex) {
       try (RestHighLevelClient client = getRestHighLevelClient()) {
           GetIndexRequest req = new GetIndexRequest(strIndex);        boolean resp = client.indices().exists(req, RequestOptions.DEFAULT);        System.out.println(strIndex + " exists: " + resp);        return resp;    } catch (Exception ex) {
           ex.printStackTrace();    }    return false;}

ES6中判断Index

ES6中无法使用上面的判断方法，只好通过BBossESStarter中的方法来实现。在yml中设定好ES相关配置后，即可通过@Autowired注解自动创建。

@AutowiredBBossESStarter bossStarter;public boolean isIndexExists(String strIndex) {
       ClientInterface client = bossStarter.getRestClient();     return client.existIndice(strIndex);}

为了使用BBossESStarter，需要在pom中增加如下包：


       
    
     com.bbossgroups.plugins
        
    
     bboss-elasticsearch-rest-jdbc
        
    
     6.1.2
        
            
                 
      
       slf4j-log4j12
                  
      
       org.slf4j
              
         
    
   
       
    
     com.bbossgroups.plugins
        
    
     bboss-elasticsearch-spring-boot-starter
        
    
     6.1.2
        
            
                 
      
       slf4j-log4j12
                  
      
       org.slf4j

在yml文件中增加如下配置：

spring:  elasticsearch:    bboss:#      elasticUser: elastic#      elasticPassword: changeme      elasticsearch:        rest:          hostNames: 127.0.0.1:9200          ##hostNames: 192.168.8.25:9200,192.168.8.26:9200,192.168.8.27:9200  ##集群地址配置        dateFormat: yyyy.MM.dd        timeZone: Asia/Shanghai        showTemplate: true        discoverHost: false      dslfile:        refreshInterval: -1      http:        timeoutConnection: 5000        timeoutSocket: 5000        connectionRequestTimeout: 5000        retryTime: 1        maxLineLength: -1        maxHeaderCount: 200        maxTotal: 400        defaultMaxPerRoute: 200        soReuseAddress: false        soKeepAlive: false        timeToLive: 3600000        keepAlive: 3600000        keystore:        keyPassword:        hostnameVerifier:

聚合（分组）查询

聚合提供了用户进行分组和数理统计的能力，可以把聚合理解成SQL中的GROUP BY和分组函数。

通过AggregationBuilder可以设定分组信息，分组结果在bucket中：

指标聚合：max/min/avg/sum/stats，获取分组中最大、最小、平均、和、统计值；

terms聚合：根据字段值项分组聚合；field按什么字段分组；size指定返回多少个分组；

date_histogram聚合：时间直方图聚合（按天、月、年等进行聚合统计）可按 year (1y), quarter (1q), month (1M), week (1w), day (1d), hour (1h), minute (1m), second (1s) 间隔聚合或指定的时间间隔聚合；

static void groupTest() {
       try (RestHighLevelClient client = getRestHighLevelClient()) {
           List
   
     lstIndex = new ArrayList<>();        lstIndex.add("stats-2020.11.03");        SearchRequest searchRequest = new SearchRequest(lstIndex.toArray(new String[0]));        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();        sourceBuilder.size(0);      //  AggregationBuilder agg = AggregationBuilders.sum("groups").field("count");       //  AggregationBuilder agg = AggregationBuilders.terms("groups").field("count").size(100);        AggregationBuilder agg = AggregationBuilders.dateHistogram("groups")                .field("addDate")                .fixedInterval(DateHistogramInterval.MINUTE)                .minDocCount(1)                .order(BucketOrder.count(true));        sourceBuilder.aggregation(agg);        searchRequest.source(sourceBuilder);        SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);        MultiBucketsAggregation termNum = searchResponse.getAggregations().get("groups");        System.out.println("Agg Terms: " + termNum.getBuckets().size());        for (MultiBucketsAggregation.Bucket entry : termNum.getBuckets()) {
               System.out.println("Agg: " + entry.getKeyAsString() + " - " + entry.getDocCount());        }    } catch (Exception ex) {
           ex.printStackTrace();    }}

转载地址：http://lwilf.baihongyu.com/

你可能感兴趣的文章

Openshift 4.4 静态 IP 离线安装系列（一）：准备离线资源