脚本化字段和运行时字段
Spring Data Elasticsearch 支持脚本化字段和运行时字段。 有关此内容的详细信息，请参阅有关脚本 （www.elastic.co/guide/en/elasticsearch/reference/current/modules-scripting.html） 和运行时字段 （www.elastic.co/guide/en/elasticsearch/reference/8.9/runtime.html） 的 Elasticsearch 文档。 在 Spring Data Elasticsearch 的上下文中，您可以使用
-
脚本化字段，用于返回在结果文档上计算并添加到返回文档的字段。
-
运行时字段，这些字段是根据存储的文档计算的，可以在查询中使用和/或在搜索结果中返回。
以下代码片段将展示您可以执行的作（这些代码片段显示了命令式代码，但反应式实现的工作方式类似）。
person 实体
这些示例中使用的 enity 是Person实体。
此实体具有birthDate以及一个age财产。
虽然 birthdate 是固定的，但 age 取决于发出查询的时间，并且需要动态计算。
import org.springframework.data.annotation.Id;
import org.springframework.data.elasticsearch.annotations.DateFormat;
import org.springframework.data.elasticsearch.annotations.Document;
import org.springframework.data.elasticsearch.annotations.Field;
import org.springframework.data.elasticsearch.annotations.ScriptedField;
import org.springframework.lang.Nullable;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import static org.springframework.data.elasticsearch.annotations.FieldType.*;
import java.lang.Integer;
@Document(indexName = "persons")
public record Person(
@Id
@Nullable
String id,
@Field(type = Text)
String lastName,
@Field(type = Text)
String firstName,
@Field(type = Keyword)
String gender,
@Field(type = Date, format = DateFormat.basic_date)
LocalDate birthDate,
@Nullable
@ScriptedField Integer age (1)
) {
public Person(String id,String lastName, String firstName, String gender, String birthDate) {
this(id, (2)
lastName,
firstName,
LocalDate.parse(birthDate, DateTimeFormatter.ISO_LOCAL_DATE),
gender,
null);
}
}
1
the age property will be calculated and filled in search results.
2
a convenience constructor to set up the test data.
Note that the age property is annotated with @ScriptedField.
This inhibits the writing of a corresponding entry in the index mapping and marks the property as a target to put a calculated field from a search response.
The repository interface
The repository used in this example:
public interface PersonRepository extends ElasticsearchRepository<Person, String> {
SearchHits<Person> findAllBy(ScriptedField scriptedField);
SearchHits<Person> findByGenderAndAgeLessThanEqual(String gender, Integer age, RuntimeField runtimeField);
}
The service class
The service class has a repository injected and an ElasticsearchOperations instance to show several ways of populating and using the age property.
We show the code split up in different pieces to put the explanations in
import org.springframework.data.elasticsearch.core.ElasticsearchOperations;
import org.springframework.data.elasticsearch.core.SearchHits;
import org.springframework.data.elasticsearch.core.query.Criteria;
import org.springframework.data.elasticsearch.core.query.CriteriaQuery;
import org.springframework.data.elasticsearch.core.query.FetchSourceFilter;
import org.springframework.data.elasticsearch.core.query.RuntimeField;
import org.springframework.data.elasticsearch.core.query.ScriptData;
import org.springframework.data.elasticsearch.core.query.ScriptType;
import org.springframework.data.elasticsearch.core.query.ScriptedField;
import org.springframework.data.elasticsearch.core.query.StringQuery;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class PersonService {
private final ElasticsearchOperations operations;
private final PersonRepository repository;
public PersonService(ElasticsearchOperations operations, SaRPersonRepository repository) {
this.operations = operations;
this.repository = repository;
}
public void save() { (1)
List<Person> persons = List.of(
new Person("1", "Smith", "Mary", "f", "1987-05-03"),
new Person("2", "Smith", "Joshua", "m", "1982-11-17"),
new Person("3", "Smith", "Joanna", "f", "2018-03-27"),
new Person("4", "Smith", "Alex", "m", "2020-08-01"),
new Person("5", "McNeill", "Fiona", "f", "1989-04-07"),
new Person("6", "McNeill", "Michael", "m", "1984-10-20"),
new Person("7", "McNeill", "Geraldine", "f", "2020-03-02"),
new Person("8", "McNeill", "Patrick", "m", "2022-07-04"));
repository.saveAll(persons);
}
1
a utility method to store some data in Elasticsearch.
Scripted fields
The next piece shows how to use a scripted field to calculate and return the age of the persons.
Scripted fields can only add something to the returned data, the age cannot be used in the query (see runtime fields for that).
public SearchHits<Person> findAllWithAge() {
var scriptedField = ScriptedField.of("age", (1)
ScriptData.of(b -> b
.withType(ScriptType.INLINE)
.withScript("""
Instant currentDate = Instant.ofEpochMilli(new Date().getTime());
Instant startDate = doc['birth-date'].value.toInstant();
return (ChronoUnit.DAYS.between(startDate, currentDate) / 365);
""")));
// version 1: use a direct query
var query = new StringQuery("""
{ "match_all": {} }
""");
query.addScriptedField(scriptedField); (2)
query.addSourceFilter(FetchSourceFilter.of(b -> b.withIncludes("*"))); (3)
var result1 = operations.search(query, Person.class); (4)
// version 2: use the repository
var result2 = repository.findAllBy(scriptedField); (5)
return result1;
}
1
define the ScriptedField that calculates the age of a person.
2
when using a Query, add the scripted field to the query.
3
when adding a scripted field to a Query, an additional source filter is needed to also retrieve the normal fields from the document source.
4
get the data where the Person entities now have the values set in their age property.
5
when using the repository, all that needs to be done is adding the scripted field as method parameter.
Runtime fields
When using runtime fields, the calculated value can be used in the query itself.
In the following code this is used to run a query for a given gender and maximum age of persons:
public SearchHits<Person> findWithGenderAndMaxAge(String gender, Integer maxAge) {
var runtimeField = new RuntimeField("age", "long", """ (1)
Instant currentDate = Instant.ofEpochMilli(new Date().getTime());
Instant startDate = doc['birthDate'].value.toInstant();
emit (ChronoUnit.DAYS.between(startDate, currentDate) / 365);
""");
// variant 1 : use a direct query
var query = CriteriaQuery.builder(Criteria
.where("gender").is(gender)
.and("age").lessThanEqual(maxAge))
.withRuntimeFields(List.of(runtimeField)) (2)
.withFields("age") (3)
.withSourceFilter(FetchSourceFilter.of(b -> b.withIncludes("*"))) (4)
.build();
var result1 = operations.search(query, Person.class); (5)
// variant 2: use the repository (6)
var result2 = repository.findByGenderAndAgeLessThanEqual(gender, maxAge, runtimeField);
return result1;
}
}
1
define the runtime field that calculates the age of a person. // see asciidoctor.org/docs/user-manual/#builtin-attributes for builtin attributes.
2
when using Query, add the runtime field.
3
when adding a scripted field to a Query, an additional field parameter is needed to have the calculated value returned.
4
when adding a scripted field to a Query, an additional source filter is needed to also retrieve the normal fields from the document source.
5
get the data filtered with the query and where the returned entites have the age property set.
6
when using the repository, all that needs to be done is adding the runtime field as method parameter.
In addition to define a runtime fields on a query, they can also be defined in the index by setting the runtimeFieldsPath property of the @Mapping annotation to point to a JSON file that contains the runtime field definitions.