ElasticSerch同时查询多个索引

一、许多场景需要查询的结果不在一个索引里面，但是elasticseach不能像别的数据库一样进行联查，所以我们可以同时查询多个索引的字段来满足需求

1、查询DSL语句

GET /_search
{
  "size": 20,
  "query": {
    "bool": {
      "minimum_should_match": 1,
      "should": [
        {
          "bool": {
            "must": [
              {
                "term": {
                  "_index": {
                    "value": "索引一"
                  }
                }
              },
              {
                "term": {
                  "索引一字段": {
                    "value": "少年歌行"
                  }
                }
              }
            ]
          }
        },
        {
          "bool": {
            "must": [
              {
                "term": {
                  "_index": {
                    "value": "索引二"
                  }
                }
              }
            ],
            "filter": {
              "term": {
                "索引而字段": "少年歌行"
              }
            }
          }
        }
      ]
    }
  },
  "sort": [
    {
      "_index": {
        "order": "desc"
      }
    },
    {
      "_score": {
        "order": "desc"
      }
    }
  ]
}

2、java

BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
QueryBuilder queryBuilder1 = QueryBuilders.boolQuery().
.must(QueryBuilders.termQuery("_index", "索引一"));
QueryBuilder queryBuilder2 = QueryBuilders.boolQuery().
.must(QueryBuilders.termQuery("_index", "索引二");
boolQueryBuilder.minimumShouldMatch(1)
                .should(bookQueryBuilder)
                .should(extensionQueryBuilder);
Query query = new NativeSearchQueryBuilder()
                .withSourceFilter(new FetchSourceFilter(new String[] {}, excludes))
                .withQuery(boolQueryBuilder)
                .withSort(SortBuilders.fieldSort("_index").order(SortOrder.DESC))
                .withSort(SortBuilders.fieldSort("_score").order(SortOrder.DESC))
                .withPageable(PageRequest.of(page - 1, size))
                .build();
SearchHits<SearchResultDto> search = esRestTemplate.search(query, SearchResultDto.class, IndexCoordinates.of("索引一", "索引二"));