ElasticSearch Spring-Data Date 格式总是很长

当使用spring-data插入具有日期类型的Elasticsearch文档时，我无法获得正确的日期格式，日期格式始终是Long。

这是java代码：实体.java

import java.util.Date;

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.FieldIndex;
import org.springframework.data.elasticsearch.annotations.FieldType;

import com.fasterxml.jackson.annotation.JsonProperty;

@Document(indexName = "entity-index", type = "entity-type")
public class Entity {
    @Id
    private String id;

    @Field(type = FieldType.Date, index = FieldIndex.not_analyzed, store = true, 
            format = DateFormat.custom, pattern = "yyyy-MM-dd'T'hh:mm:ss.SSS'Z'")
    private Date createDate;

    private String system;
    private double score;

    @Field(type = FieldType.Date, format = DateFormat.date_optional_time)
    @JsonProperty(value = "@timestamp")
    private Date updateDate;
    // omit setter and getter 
}

这是测试

public class EntityDAOTest {
    @Autowired
    private ElasticsearchTemplate template;

    @Before
    public void init() {
        template.createIndex(Entity.class);
        template.putMapping(Entity.class);
    }


    @Test
    public void testCreate() {
        Entity entity = new Entity();
        entity.setId("5");
        entity.setCreateDate(new DateTime(2015,05,27,0,0).toDate());
        entity.setUpdateDate(new DateTime(2015,05,27,0,0).toDate());
        entity.setSystem("systemC");
        entity.setScore(5.7);
        IndexQuery query = new IndexQueryBuilder().withObject(entity).withId(entity.getId()).build();
        template.index(query);
    }

我可以获取所创建实体的映射：

{
   "entity-index": {
      "mappings": {
         "entity-type": {
            "properties": {
               "@timestamp": {
                  "type": "long"
               },
               "createDate": {
                  "type": "date",
                  "store": true,
                  "format": "yyyy-MM-dd'T'hh:mm:ss.SSS'Z'"
               },
               "id": {
                  "type": "string"
               },
               "score": {
                  "type": "double"
               },
               "system": {
                  "type": "string"
               },
               "updateDate": {
                  "type": "date",
                  "format": "date_optional_time"
               }
            }
         }
      }
   }
}

但是，当我搜索它时，我得到以下文档：curl -X GET /entity-index/_search

 {
               "id": "5",
               "createDate": 1432656000000,
               "system": "systemC",
               "score": 5.7,
               "@timestamp": 1432656000000
 }

和 日期字段都是长类型，我如何获得日期格式：'2015-08-17T12：00：00.000'？