com.fasterxml.jackson.databind.JsonMapping异常：对象不是声明类的实例

Question

我有一个CookingEvent.class，它是Event.class的子类，hibernate继承策略是@ Inheritance(strategy = Inheritance type。已加入)。当我试图发送一个列表对象作为get响应时。我不例外

2016-08-25 11:49:22.351错误11944---[nio-8189-exec-1]o.a.c.c.c.[.[/]。[servletContainer]：Servlet。路径为[]的上下文中servlet[servletContainer]的service（）引发异常[org.glassfish.jersey.server.ContainerException:com.fasterxml.jjackson.databind.JsonMappingException:对象不是声明类的实例（通过引用链：java.util.ArrayList[0]-

java.lang.IllegalArgumentException：对象不是sun.reflect.NativeMethodAccessorImpl处声明类的实例。位于com.fasterxml.jockson.databind.ser.BeanPropertyWriter.get（BeanProportyWriter java:726）的sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethAccessorInpl.java:62）的invoke0（本机方法）com.fasterxml.jockson.databind.ser.BeanPropertyWriter.serializeAsField（BeanProportyWriter.java:506）位于com.faster xml.joctson.databond.ser.std.BeanSerializerBase.serializationFields（BeanSerializerBase.java:644）位于com.sfasterxml.jockson.databind.ser.BeanSerializer.serializer（BeanArializer.java:152）

@Entity
@Table(name = "users")
@JsonAutoDetect
public class Users  implements java.io.Serializable {

  @JsonBackReference
    private List<Event> eventByUser = new ArrayList<Event>(
            0);

    @Id
    @GeneratedValue
    @Column(name = "USER_ID", unique = true)
    public Long getUserId() {
        return userIds;
    }
    @OneToMany(fetch = FetchType.LAZY, mappedBy = "user")
    @Fetch(FetchMode.JOIN)
    @JsonInclude(JsonInclude.Include.NON_EMPTY)
    @JsonIgnore
    public List<Event> getEventByUser() {
        return eventByUser;
    }
}


  @Entity
    @Table(name = "EVENT")
    @Inheritance(strategy=InheritanceType.JOINED)
    public class Event  implements java.io.Serializable {

        private Integer eventId;

        @Id
        @GeneratedValue
        @Column(name = "COOKING_EVENT_ID", unique = true)
        public Integer getEventId() {
            return eventId;
        }
        private Users user;

        @ManyToOne(fetch = FetchType.LAZY)
    @Fetch(FetchMode.SELECT)
    @JsonIgnore
    @JsonInclude(JsonInclude.Include.NON_EMPTY)
    @JoinColumn(name = "ASSIGNED_USER_ID", nullable = false)
    @JsonManagedReference
    public Users getUser() {
        return user;
    }

        public void setEventId(Integer eventId) {
            this.eventId = eventId;
        }



 @Entity
    @Table(name = "COOKING_REQUEST_EVENT") @PrimaryKeyJoinColumn(name="EVENT_ID") 
public class CookingRequestEvent extends Event implements java.io.Serializable {

        //Other Variables along with setters and getters 

        }

我有一个泽西岛控制器，如下所示，它返回一个列表

  @GET
        @Path("/cookingEventsByUser/{userId}")
        @Produces({ MediaType.APPLICATION_JSON})
        public List<CookingEvent>  getEventsById(@PathParam("userId") Long id)
                throws JsonGenerationException, JsonMappingException, IOException {
          List<CookingEvent> events  = new ArrayList<CookingEvent>();
         events =  cookingEventServices.getCookingEventsByUser(id);

        } 

我正在使用Spring Boot Jersey hibernate

Answer 1

问题已解决。

已添加

@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include =As.PROPERTY, property = "data")
@JsonSubTypes({ @Type(value = CookingEvent.class, name = "cookingEvent"), @Type(value = CookingRequestEvent.class, name = "cookingRequest") })