JAVA Rest High Level Client如何取聚合后的数据
对于刚刚学习es的童鞋来说,很容易不清楚怎么获取客户端对es文档的聚合结果,下面就演示一下模仿DSL写聚合,然后获取到聚合的结果。
一, 对于下面这个简单的聚合,目的是对于文档全文匹配,聚合颜色字段。把满足匹配的文档放入自定义名称的colors桶中,参照《elasticsearch权威指南》的范围限定聚合
1 { 2 "size" : 0, 3 "query" : { 4 "match_all" : {} 5 }, 6 "aggs" : { 7 "colors" : { 8 "terms" : { 9 "field" : "color" 10 } 11 } 12 } 13 }
二, 对照着这个DSL写我们的java rest client api的调用方法,供业务层调用
1 /** 2 * ES中查询所有color 3 * 4 * @param indices 5 * @return 6 */ 7 public SearchResponse getAllColor(String... indices) { 8 SearchRequest searchRequest = new SearchRequest(indices); 9 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder().size(0); 10 searchSourceBuilder.query(QueryBuilders.matchAllQuery()); 11 TermsAggregationBuilder builder = AggregationBuilders.terms("colors").field("color"); 12 searchSourceBuilder.aggregation(builder); 13 searchRequest.source(searchSourceBuilder); 14 15 try { 16 return client.getHighLevelClient().search(searchRequest); 17 } catch (IOException e) { 18 throw new BizException("聚合失败:{}", e.getCause()); 19 } 20 }
三, 在我们的业务层调用上文中的getAllColor方法获取response,对response解析,获取聚合的结果
2 * 颜色信息 3 * 4 * @return 5 */ 6 public List<String> getAllColorInfo() { 7 SearchResponse response = highRestHelper.getAllColor(getIndices()); 8 Aggregations aggregations = response.getAggregations(); 9 ParsedStringTerms colorTerms = aggregations.get("app_group"); 10 List<String> colors = new ArrayList<>(); 11 List<? extends Terms.Bucket> buckets = colorTerms.getBuckets(); 12 for (Terms.Bucket bucket : buckets) { 13 String appName = bucket.getKey().toString(); 14 colors.add(appName); 15 } 16 return colors; 17 }
至此即可获取所有的聚合结果,只要能够参照DSL,转换成相应的api调用,那么解析过程完全可以复用。