如何使用spring-data-elasticsearch存储java枚举

Question

public enum Smoking {
    NO("No"),YES("Yes");
}

如何使用spring-data-elasticsearch存储java枚举，我想存储Yes、No并搜索相同的枚举

Answer 1

为此，您可以为Enum提供自定义转换器，以便将其从字符串转换为字符串。我想您希望将此属性作为Elasticsearch中的关键字，而不是进行分析。

下面是Smoking枚举的一个实现，我在其中添加了必要的转换器作为嵌套枚举(我更喜欢使用枚举作为转换器的单一实现)：

import org.springframework.core.convert.converter.Converter;
import org.springframework.data.convert.ReadingConverter;
import org.springframework.data.convert.WritingConverter;

public enum Smoking {
    YES("yes"),
    NO("No");

    private String elasticsearchName;

    Smoking(String elasticsearchName) {
        this.elasticsearchName = elasticsearchName;
    }

    @WritingConverter
    public enum SmokingToStringConverter implements Converter<Smoking, String> {

        INSTANCE;

        @Override
        public String convert(Smoking source) {
            return source.elasticsearchName;
        }
    }

    @ReadingConverter
    public enum StringToSmokingConverter implements Converter<String, Smoking> {

        INSTANCE;

        @Override
        public Smoking convert(String source) {
            for (Smoking smoking : Smoking.values()) {
                if (smoking.elasticsearchName.equals(source)) {
                    return smoking;
                }
            }
            return null;
        }
    }
}

需要注册转换器，这可以通过添加elasticsearchCustomConversions()的自定义实现在configuration类中完成(请参阅https://docs.spring.io/spring-data/elasticsearch/docs/4.0.4.RELEASE/reference/html/#elasticsearch.clients.rest上有关配置客户端的文档

@Override
public ElasticsearchCustomConversions elasticsearchCustomConversions() {
    return new ElasticsearchCustomConversions(Arrays.asList(
        Smoking.SmokingToStringConverter.INSTANCE,
        Smoking.StringToSmokingConverter.INSTANCE)
    );
}

然后在实体中使用枚举类：

@Field(type = FieldType.Keyword)
private Smoking smoking;

仅此而已，枚举值以所需的形式存储在Elasticsearch中。