elasticsearch实现简单的脚本排序(script sort)

Posted 2023-01-13

1、背景

我有一堆学生数据，其中湖北省的学生需要排在所有数据的最前面。其余省正序排序，对于同一个省的数据，按照年龄倒序排序。

2、分析

对于上方的排序需求，湖北省的学生数据需要排在前端，但是湖北省并不是一个字段，那么这个时候改如何实现呢？对于这种场景我们很容易就想到需要脚本script sort来实现。

3、构建数据

3.1 mapping

PUT /index_person

  "settings": 
    "number_of_shards": 1
  ,
  "mappings": 
    "properties": 
      "id":
        "type": "long"
      ,
      "name": 
        "type": "keyword"
      ,
      "age": 
        "type": "integer"
      ,
      "province":
        "type": "keyword"
      
    
  

3.2 插入数据

PUT /index_person/_bulk
"index":"_id":1
"id":1, "name":"张三","age":18,"province":"湖北"
"index":"_id":2
"id":2, "name":"李四","age":19,"province":"湖北"
"index":"_id":3
"id":3, "name":"王武","age":20,"province":"西安"
"index":"_id":4
"id":4, "name":"赵六","age":21,"province":"西安"
"index":"_id":5
"id":5, "name":"钱七","age":22,"province":"上海"

4、实现

4.1 根据省升序排序

4.1.1 dsl

GET index_person/_search

  "query": 
    "match_all": 
  ,
  "sort": [
    
      "province": 
        "order": "asc"
      
    
  ]

4.1.2 运行结果

可以看到省升序的排序顺序为 上海、湖北、西安。

4.2 湖北省排第一

4.2.1 dsl

GET index_person/_search

  "query": 
    "match_all": 
  ,
  "sort": [
    
      "_script": 
        "type": "number",
        "order": "desc",
        "script": 
          "lang": "painless",
          "source": """
                      if(params[_source][province] == 湖北)
                        1
                       else 
                        0
                      
                    """
        
      
    
  ]

4.2.2 运行结果

通过如上的 script sort排序之后，就可以看到 湖北省已经是排到第一位了。

4.3 湖北省排第一，其余省升序排序，按照年龄倒序

4.3.1 dsl

GET index_person/_search

  "query": 
    "match_all": 
  ,
  "sort": [
    
      "_script": 
        "type": "number",
        "order": "desc",
        "script": 
          "lang": "painless",
          "source": """
                      if(params[_source][province] == 湖北)
                        1
                       else 
                        0
                      
                    """
        
      
    ,
    
      "province": 
        "order": "asc"
      ,
      "age": 
        "order": "desc",
        "missing": "_last"
      
    
  ]

4.3.2 java代码

@Test
@DisplayName("脚本排序，固定的某个值的数据排在前面，其余的数据按照别的字段排序")
public void test01() throws IOException 
    SearchRequest request = SearchRequest.of(searchRequest ->
            searchRequest.index("index_person")
                    .query(query -> query.matchAll(matchAll -> matchAll))
                    .size(100)
                    .sort(sort ->
                            sort.script(sortScript ->
                                    sortScript.type(ScriptSortType.Number)
                                            .order(SortOrder.Desc)
                                            .script(script ->
                                                    script.inline(inline ->
                                                            inline.source("if(params[_source][province] == params.province)\\n" +
                                                                            "                        1\\n" +
                                                                            "                       else \\n" +
                                                                            "                        0\\n" +
                                                                            "                      ")
                                                                    .params("province", JsonData.of("湖北"))
                                                    )
                                            )
                            )
                    )
                    .sort(sort ->
                            sort.field(field ->
                                    field.field("province").order(SortOrder.Asc)
                            )
                    )
                    .sort(sort ->
                            sort.field(field ->
                                    field.field("age").order(SortOrder.Desc).missing("_last")
                            )
                    )
    );

    System.out.println("request: " + request);
    SearchResponse<Object> response = client.search(request, Object.class);
    System.out.println("response: " + response);

4.3.3 运行结果

5、完整代码

1、https://gitee.com/huan1993/spring-cloud-parent/blob/master/es/es8-api/src/main/java/com/huan/es8/script/ScriptFieldSort.java

6、参考文档

1、https://www.elastic.co/guide/en/elasticsearch/reference/7.17/sort-search-results.html