Spring Data Rest - 如何更改 JSON 摘要集合的序列化类

Question

我使用 Spring Boot v1.2.5 并具有以下单个 table 继承实体：

@Entity    
@table(name="view_items")
@DiscriminatorColumn(name="type")
public abstract class ViewItem {
   private int position;     
}

@Entity
@DiscriminatorValue(value="table")
public class Table extends ViewItem {}

@Entity
@DiscriminatorValue(value="chart")
public class Chart extends ViewItem {}

public interface ViewItemRepository 
    extends JpaRepository<ViewItem, Integer>{}

以及以下关联：

@Entity
@Table(name="views")
public class View {

    @OneToMany
    @JoinColumn(name="view_id")
    @OrderBy("position")
    private List<ViewItem> viewItems = new ArrayList<ViewItem>();

    ...
}

调用 GET /views/{id}/viewItems return 按子类类型排序的集合（为了便于阅读，一些部分已被删除）：

HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Content-Type: application/hal+json;charset=UTF-8
Transfer-Encoding: chunked

Date: Wed, 23 Sep 2015 07:41:13 GMT

{
  "_embedded" : {        
    "tables" : [ {
      "position": 4,          
        ...
      "_links" : {
        "self" : {
          "href" : "http://localhost:8080/viewItems/3"
        }
      }
    } ],
    "charts" : [ {
      "position": 2,
        ...
      "_links" : {
        "self" : {
          "href" : "http://localhost:8080/viewItems/2"
        }
      }
    } ]
  }

是否有一种简单的方法来更改 JSON 序列化 view_items 像这样按位置排序？ :

{
  "_embedded" : {        
    "2": {
      "type": "chart",
        ...
      "_links" : {
        "self" : {
          "href" : "http://localhost:8080/viewItems/2"
        }
    },
    "4": {
      type: "table",
       ...
      "_links" : {
        "self" : {
          "href" : "http://localhost:8080/viewItems/3"
        }
  }

Answer 1

所以我找到了答案。

将 View 实体的 ViewItems 集合映射类型从 List 替换为 Map 并在 [=] 上添加只读 type 字段16=] 实体成功了：

@Entity
@Table(name="views")
public class View {

    @OneToMany
    @JoinColumn(name="view_id")
    @MapKey("position")
    private Map<Integer,ViewItem> viewItems = new HashMap<Integer,ViewItem>();
    ...
}

@Entity    
@table(name="view_items")
@DiscriminatorColumn(name="type")
public abstract class ViewItem {

   @Column(insertable = false, updatable = false)
   public String type;

   ...  
}

编辑

几个月后，感谢@aux（参见here) here is the solution. A RelProvider class must be implemented, as explained here。

Spring Data Rest - 如何更改 JSON 摘要集合的序列化类

Spring Data Rest - How to change the JSON serialization of a Collection of Abstract Classes

java

spring-data-rest

Spring Data Rest - 如何更改 JSON 摘要集合的序列化 类

Spring Data Rest - How to change the JSON serialization of a Collection of Abstract Classes

java

spring-data-rest

Spring Data Rest - 如何更改 JSON 摘要集合的序列化类