ElasticSearch批量查询JavaApi实现

快来打我* 2022-11-26 04:57 399阅读 0赞

> ElasticSearch 版本 6.8

## 背景 ##

Elasticsearch 允许通过一次查询请求执行多个文档的检索，虽然 Elasticsearch 内部还是一条一条去检索，但是这样可以避免多次请求造成的单独网络开销，相对于一个一个的检索，这样的效率更高。  
之前项目处理是一条一条去检索，后来改造为批处理后，单处理差不多优化了10s的效率左右，测试数据量大概在2w左右

## java实现 ##

[es官方文档][es]

相比单处理，我们批处理肯定是要先获取 单个 SearchRequest， 然后再装入一个请求中类似list中,然后发一次请求

### 获取单个请求 ###

public SearchRequest getQuery(Drug drug, Boolean specFlag) { 
    
            SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
    
    
            BoolQueryBuilder builder = QueryBuilders.boolQuery();
            BoolQueryBuilder nameMatch = QueryBuilders.boolQuery().minimumShouldMatch(1)
                    .should(QueryBuilders.matchQuery("drugName",drug.getDrugName()))
                    .should(QueryBuilders.matchQuery("productName",drug.getDrugName()));
    
    
    
            BoolQueryBuilder must = QueryBuilders.boolQuery().minimumShouldMatch(2)
                    .should(nameMatch)
                    .should(QueryBuilders.matchQuery("companyName", drug.getCompany()))
                    .should(QueryBuilders.matchQuery("approvalIndex", drug.getApproval()));
    
            builder.must(must);
            if (specFlag) { 
                BoolQueryBuilder specMatch = QueryBuilders.boolQuery().minimumShouldMatch(1)
                        .should(QueryBuilders.matchQuery("specIndex",drug.getSpec()))
                        .should(QueryBuilders.matchQuery("otherSpec",drug.getSpec()));
                builder.must(specMatch);
                builder.should(QueryBuilders.termQuery("specIndex.full", drug.getSpec()))
                        .should(QueryBuilders.termQuery("otherSpec.full", drug.getSpec()));
    
            }
            // 分页只要第一条查询结果
            searchSourceBuilder.query(builder).from(0).size(1);
    
    
            SearchRequest firstSearchRequest = new SearchRequest();
            firstSearchRequest.source(searchSourceBuilder);
    
            return firstSearchRequest;
    
        }

### 构造批处理请求 ###

List<SearchRequest> searchRequests = Lists.newArrayListWithExpectedSize(sources.size());
    // getQuery 为上面方法
    SearchRequest query = clearSearch.getQuery(drug, false);
                searchRequests.add(query);

### 发送请求获取查询结果 ###

@Autowired
    ElasticsearchRestTemplate restTemplate;
    
     public List<DscStandardProduct> clearProduct(List<SearchRequest> searchRequests) { 
    
            List<DscStandardProduct> products = new ArrayList<>();
            MultiSearchRequest request = new MultiSearchRequest();
            // 添加批量查询
            for (SearchRequest searchRequest : searchRequests) { 
                request.add(searchRequest);
            }
    
            try { 
                MultiSearchResponse multiResponse = restTemplate.getClient().msearch(request, RequestOptions.DEFAULT);
                for (MultiSearchResponse.Item item : multiResponse.getResponses()) { 
                    SearchHits hits = item.getResponse().getHits();
    
                    if (CollectionUtil.isEmpty(hits)) { 
                        products.add(null);
                        continue;
                    }
                    for (SearchHit hit : hits) { 
                        String sourceAsString = hit.getSourceAsString();
                        DscStandardProduct product = JSONObject.parseObject(sourceAsString, DscStandardProduct.class);
                        products.add(product);
                    }
    
                }
    
            } catch (IOException e) { 
                e.printStackTrace();
            }
    
            return products;
    
        }

[es]: https://www.elastic.co/guide/en/elasticsearch/client/java-rest/6.8/java-rest-high-search.html