regex - ElasticSearch正则表达式查询不起作用

Question

我将ES 2.4.6与Java 8配合使用，并且创建了一个文档对象，如下所示:

@Document(indexName = "airports", type = "airport")
public class Airport {

  @Id
  private String id;

  @Field(type = String)
  private String name;
}

并且我成功地搜索到ES的几个机场对象，如下
名称: “旧金山”，“圣马特奥”，“圣地亚哥”，“帕洛阿尔托”，“大圣”
ES中的JSON内容如下所示:

{
  "took": 2,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 5,
    "max_score": 1,
    "hits": [
      {
        "_index": "airports",
        "_type": "airport",
        "_id": "SSMlsTWIYefbXHCnYEwEY",
        "_score": 1,
        "_source": {
          "id": "SSMlsTWIYefbXHCnYEwEY",
          "name": "Santiago"
        }
      },
      {
        "_index": "airports",
        "_type": "airport",
        "_id": "LlDcKuywPjURNeIISjXLjC",
        "_score": 1,
        "_source": {
          "id": "LlDcKuywPjURNeIISjXLjC",
          "name": "San Mateo"
        }
      },
      {
        "_index": "airports",
        "_type": "airport",
        "_id": "CVIjEHYphSmZIjYbHCMwtkqfKWtEHVh",
        "_score": 1,
        "_source": {
          "id": "CVIjEHYphSmZIjYbHCMwtkqfKWtEHVh",
          "name": "San Francisco"
        }
      },
      {
        "_index": "airports",
        "_type": "airport",
        "_id": "gbntKR",
        "_score": 1,
        "_source": {
          "id": "gbntKR",
          "name": "Palo Alto"
        }
      },
      {
        "_index": "airports",
        "_type": "airport",
        "_id": "bKosUdHeseMMboyaejv",
        "_score": 1,
        "_source": {
          "id": "bKosUdHeseMMboyaejv",
          "name": "Big San"
        }
      }
    ]
  }
}

然后我有以下curl命令以使用正则表达式查询来查找所有机场
以 “san”开头的名字忽略大小写，我这样做了:

curl -XGET 'localhost:9200/airports/airport/_search?pretty' -H 'Content-Type: application/json' -d'
{
    "query": {
        "regexp":{
            "name": "^(?i)san"
        }
    }
}
'

我使用正则表达式“^(？i)san”直接匹配这些机场名称，
它按预期工作:

String regex = "^(?i)san";
assertTrue("San Francisco".matches(regex));
assertTrue("San Mateo".matches(regex));
assertTrue("Santiago".matches(regex));
assertTrue(!"Big San".matches(regex));

那么有人知道为什么ES regex查询返回空结果吗？现在，如果
我使用 “san” 作为正则表达式，所有4个名称都返回，并且如果我使用 “San” ，则没有任何返回。

Answer 1

您可以将Match Phrase Prefix用于上述问题。

 {
  "query": {
    "match_phrase_prefix": {
       "name": "San"
      }
    }
 }

查看是否可以解决您的问题。