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jackson反序列化,2个字段自引用同一类(自引用循环)

self-reference jackson spring java

GrooveRage · 技术社区 · 8 年前

我有以下类引用自身:

@Entity
@Inheritance(strategy = TABLE_PER_CLASS)
//@JsonIdentityInfo(property="rowId", generator = ObjectIdGenerators.PropertyGenerator.class)
public abstract class AbstractEntity implements Serializable {
    /**
     * 
     */
    private static final long serialVersionUID = 568799551343430329L;

    @OneToOne(optional=false, fetch=FetchType.EAGER)
    @JoinColumn(name="createdBy")
    protected User createdBy;
    @OneToOne(optional=false, fetch=FetchType.EAGER)
    @JoinColumn(name="lastUpdatedBy")
    protected User lastUpdatedBy;

    @Id
    @GeneratedValue(strategy = GenerationType.TABLE)
    @Column(unique = true, nullable = false, updatable = false, length = 7)
    private Integer rowId;

    public User getCreatedBy() {
        return this.createdBy;
    }

    public void setCreatedBy(User createdBy) {
        this.createdBy = createdBy;
    }

    public User getLastUpdatedBy() {
        return this.lastUpdatedBy;
    }

    public void setLastUpdatedBy(User lastUpdatedBy) {
        this.lastUpdatedBy = lastUpdatedBy;
    }

    public Integer getRowId() {
        return this.rowId;
    }

    public void setRowId(Integer RowId) {
        this.rowId = RowId;
    }

    public String toString() {
        return "[Id]:" + this.rowId + " - [CreatedBy]:" + this.createdBy;
    }
}

然后我有一节课 User 扩展此类和RepositoryUser界面:

public interface RepositoryUser extends CrudRepository<User, Integer> {

}

和控制器:

@Controller
@RequestMapping(path = "/user")
public class ServiceUser {
    @Autowired
    private RepositoryUser repositoryUser;

    @GetMapping(path="/all", produces = "application/json; charset=UTF-8", headers = "Accept=application/json")
    public @ResponseBody Iterable<User> getAllUsers() {
        return repositoryUser.findAll();
    }

    @PostMapping(path="/add", consumes="application/json")
    public @ResponseBody User createOneUser(@RequestBody User user) {
        System.out.println(user);
        return repositoryUser.save(user);
    }
}

我的问题是,我在同一个类中两次引用用户(createdby和lastupdedby),要么我尝试了JSonIdentityInfo、Jsonmanaged和jsonback,但什么都不起作用。正确地

我需要能够 { 用户1数据,包括创建人和上次更新人用户2数据,包括创建人和上次更新人 }

当我添加时,我需要设置创建记录的用户。

你能帮帮我吗?

谢谢!

1 回复 | 直到 8 年前

Tinus Jackson 8 年前

您可以使用StdSerializer编写/尝试自定义序列化程序。

CustomJsonSerializer示例。注意:没有运行代码。

public class CustomJsonSerializer extends StdSerializer<AbstractEntity> {

  public CustomJsonSerializer() {
    this(null);
  }

  public CustomJsonSerializer(Class<AbstractEntity> t) {
    super(t);
  }

  @Override
  public void serialize(AbstractEntity value, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonGenerationException {
    Field[] fields = value.getClass().getDeclaredFields();
    jgen.writeStartObject();

    for (Field field : fields) {
        field.setAccessible(true);

       try {
           // Do the proper field mapping for field types . Object type example
           jgen.writeObjectField(field.getName(), field.get(value));

        } catch (Exception e) {
          // catch error
        }
    }

    jgen.writeEndObject();
  }
}

然后在Rest方法中使用@JsonSerialize

@JsonSerialize(using = CustomJsonSerializer.class)
@GetMapping(path="/all", produces = "application/json; charset=UTF-8", headers = "Accept=application/json")
public @ResponseBody Iterable<User> getAllUsers() {
    return repositoryUser.findAll();
}

请看 Custom Serializer 和 StdSerializer

可能的不同解决方案 jackson-bidirectional infinite-recursion