有multiple ways来实现你想要的，但最简单的是使用prefix query，如果你只是把你的数据直接索引到Elasticsearch而不定义Map，它会自动为你创建两个字段，并且在.keyword字段上你可以使用如下所示的前缀查询。

索引示例文档

PUT <your-es-index>/_doc/1

{
    "title" : "what is my name"
}

PUT <your-es-index>/_doc/2

{
    "title" : "what is google"
}

PUT <your-es-index>/_doc/3

{
    "title" : "what is stackoverflow"
}

PUT <your-es-index>/_doc/4

{
    "title" : "how to search"
}

搜索查询

POST /搜索（_S）

{
    "query": {
        "prefix": {
            "title.keyword": {
                "value": "what is"
            }
        }
    }
}

您预期的搜索结果

"hits": [
            {
                "_index": "72391510",
                "_id": "1",
                "_score": 1.0,
                "_source": {
                    "title": "what is my name"
                }
            },
            {
                "_index": "72391510",
                "_id": "2",
                "_score": 1.0,
                "_source": {
                    "title": "what is google"
                }
            },
            {
                "_index": "72391510",
                "_id": "3",
                "_score": 1.0,
                "_source": {
                    "title": "what is stackoverflow"
                }
            }