Elasticsearch的搜索结果可以通过以下参数进行控制：
from：指定搜索结果的起始位置，默认为0。
size：指定返回的文档数量，默认为10。
sort：指定搜索结果的排序方式，可以按照字段升序或降序排列。
query：指定搜索的查询条件，可以使用各种查询语句进行搜索。
filter：指定搜索的过滤条件，可以使用各种过滤语句进行过滤。
highlight：指定搜索结果中需要高亮显示的字段。
aggregations：指定搜索结果的聚合方式，可以对搜索结果进行分组统计。
suggest：指定搜索建议，可以根据用户输入的关键词提供搜索建议。
1. 数据准备
PUT /my_index/_doc/1
{
"title": "文雅酒店",
"content": "青岛",
"price": 556
}
PUT /my_index/_doc/2
{
"title": "金都嘉怡假日酒店",
"content": "北京",
"price": 337
}
PUT /my_index/_doc/3
{
"title": "金都欣欣酒店",
"content": "天津",
"price": 200
}
PUT /my_index/_doc/4
{
"title": "金都酒店",
"content": "北京",
"price": 500
}
2. ElasticSearch 搜索结果返回指定的字段
在 ElasticSearch 中，可以使用 _source 字段来指定返回的字段。默认情况下，ElasticSearch 返回匹配文档的所有字段，但是可以通过 _source 字段来指定只返回需要的字段，这样可以减少网络传输和解析的开销，提高搜索性能。
以下是一个示例，假设我们有一个名为 my_index 的索引，其中包含 title 、content和price 这3个字段，我们只需要返回 title 字段：
GET /my_index/_search
{
"_source": ["title"],
"query": {
"match": {
"content": "北京"
}
}
}
在上面的示例中，我们使用 _source 字段来指定只返回 title 字段，同时使用 match 查询来搜索包含 北京 的文档。
{
"took" : 2,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 2,
"relation" : "eq"
},
"max_score" : 1.3862944,
"hits" : [
{
"_index" : "my_index",
"_type" : "_doc",
"_id" : "2",
"_score" : 1.3862944,
"_source" : {
"title" : "金都嘉怡假日酒店"
}
},
{
"_index" : "my_index",
"_type" : "_doc",
"_id" : "4",
"_score" : 1.3862944,
"_source" : {
"title" : "金都酒店"
}
}
]
}
}
如果需要返回多个字段，可以将字段名添加到 _source 字段的数组中，如下所示：
GET /my_index/_search
{
"_source": ["title", "content"],
"query": {
"match": {
"content": "北京"
}
}
}
在上面的示例中，我们指定返回 title 和 content 两个字段。文章来源：https://www.toymoban.com/news/detail-442676.html
需要注意的是，如果某个字段被存储在索引中，但是没有被指定在 _source 字段中，那么在搜索结果中将无法获取该字段的值。因此，在创建索引时，需要根据实际需求来决定哪些字段需要被存储在索引中。文章来源地址https://www.toymoban.com/news/detail-442676.html
3. SpringBoot整合ES 搜索结果返回指定的字段
@Slf4j
@Service
public class ElasticSearchImpl {
@Autowired
private RestHighLevelClient restHighLevelClient;
public void searchUser() throws IOException {
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
// query 参数
MatchQueryBuilder matchQueryBuilder = new MatchQueryBuilder("content","北京");
searchSourceBuilder.query(matchQueryBuilder);
// _source 参数
searchSourceBuilder.fetchSource(new String[]{"title","content"},null);
SearchRequest searchRequest = new SearchRequest(new String[]{"my_index"},searchSourceBuilder);
SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
// 搜索结果
SearchHits searchHits = searchResponse.getHits();
SearchHit[] hits = searchHits.getHits();
for (SearchHit hit : hits) {
// hits.hits._source：匹配的文档的原始数据
String sourceAsString = hit.getSourceAsString();
System.out.println("sourceAsString = " + sourceAsString);
}
System.out.println(searchResponse);
}
}
{
"took": 1,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 2,
"relation": "eq"
},
"max_score": 1.3862944,
"hits": [
{
"_index": "my_index",
"_type": "_doc",
"_id": "2",
"_score": 1.3862944,
"_source": {
"title": "金都嘉怡假日酒店",
"content": "北京"
}
},
{
"_index": "my_index",
"_type": "_doc",
"_id": "4",
"_score": 1.3862944,
"_source": {
"title": "金都酒店",
"content": "北京"
}
}
]
}
}
4. 源码接口
public final class SearchSourceBuilder implements Writeable, ToXContentObject, Rewriteable<SearchSourceBuilder> {
/**
* Indicates whether the response should contain the stored _source for every hit
*/
public SearchSourceBuilder fetchSource(boolean fetch) {
FetchSourceContext fetchSourceContext = this.fetchSourceContext != null ? this.fetchSourceContext
: FetchSourceContext.FETCH_SOURCE;
this.fetchSourceContext = new FetchSourceContext(fetch, fetchSourceContext.includes(), fetchSourceContext.excludes());
return this;
}
/**
* Indicate that _source should be returned with every hit, with an
* "include" and/or "exclude" set which can include simple wildcard
* elements.
*
* @param include
* An optional include (optionally wildcarded) pattern to filter
* the returned _source
* @param exclude
* An optional exclude (optionally wildcarded) pattern to filter
* the returned _source
*/
public SearchSourceBuilder fetchSource(@Nullable String include, @Nullable String exclude) {
return fetchSource(include == null ? Strings.EMPTY_ARRAY : new String[] { include }, exclude == null ? Strings.EMPTY_ARRAY
: new String[] { exclude });
}
/**
* Indicate that _source should be returned with every hit, with an
* "include" and/or "exclude" set which can include simple wildcard
* elements.
*
* @param includes
* An optional list of include (optionally wildcarded) pattern to
* filter the returned _source
* @param excludes
* An optional list of exclude (optionally wildcarded) pattern to
* filter the returned _source
*/
public SearchSourceBuilder fetchSource(@Nullable String[] includes, @Nullable String[] excludes) {
FetchSourceContext fetchSourceContext = this.fetchSourceContext != null ? this.fetchSourceContext
: FetchSourceContext.FETCH_SOURCE;
this.fetchSourceContext = new FetchSourceContext(fetchSourceContext.fetchSource(), includes, excludes);
return this;
}
/**
* Indicate how the _source should be fetched.
*/
public SearchSourceBuilder fetchSource(@Nullable FetchSourceContext fetchSourceContext) {
this.fetchSourceContext = fetchSourceContext;
return this;
}
}
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