Elasticsearch的补全提示

Elasticsearch提供了Completion Suggester来实现补全提示功能。具体实现方式如下：
1. 定义Mapping，使用“completion” type索引数据。
2. 运行“suggest”查询，得到搜索建议。

以下是一个例子，演示如何使用Completion Suggester实现补全提示功能：
1. 定义Mapping，使用“completion” type。

PUT /suggest_test
{
  "mappings": {
    "properties": {
      "suggest": {
        "type": "completion"
      }
    }
  }
}

2. 索引数据。

PUT /suggest_test/_doc/1
{
  "suggest": {
    "input": ["apple", "pie"],
    "weight": 10
  }
}

3. 运行“suggest”查询，得到搜索建议。

GET /suggest_test/_search
{
  "suggest": {
    "my-suggestion": {
      "prefix": "app",
      "completion": {
        "field": "suggest"
      }
    }
  }
}

返回结果如下：

{
  "suggest": {
    "my-suggestion": [
      {
        "text": "app",
        "offset": 0,
        "length": 3,
        "options": [
          {
            "text": "apple",
            "_index": "suggest_test",
            "_type": "_doc",
            "_id": "1",
            "_score": 10.0,
            "_source": {
              "suggest": {
                "input": [
                  "apple",
                  "pie"
                ],
                "weight": 10
              }
            }
          }
        ]
      }
    ]
  }
}