import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import javax.persistence.*;
import java.io.Serializable;
import java.util.Date;
import java.util.List;
/**
* Created by change.
* 任務
*/
@Entity
@Table(name = "task")
@Data
public class TaskEntity implements Serializable {
private static final long serialVersionUID = -8305163456196952851L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column
private String target;
@Column
private int type;
@Column(name = "start_at")
private Date startAt;
@Column(name = "end_at")
private Date endAt;
@Column(name = "data_path")
private String dataPath;
@Column
private int status;
@Column(name = "status_text")
private String statusText;
@Column
private String description;
@OneToMany(cascade = CascadeType.ALL, mappedBy = "taskEntity")
private List<SearchPoliceEntity> searchPoliceEntityList;
}
import com.fasterxml.jackson.annotation.JsonBackReference;
import javax.persistence.*;
import java.io.Serializable;
/**
* Created by challenge.
* 搜索策略
*/
@Entity
@Table(name = "search_police")
@Data
public class SearchPoliceEntity implements Serializable {
private static final long serialVersionUID = -2766200716493656577L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column
private int rate;
@Column
private String level;
@Column(name = "snr")
private String SNR;
@ManyToOne
@JoinColumn(name = "task_id")
@JsonBackReference
private TaskEntity taskEntity;
}
json序列化的對象中存在雙向引用會導致的無限遞歸(infinite recursion)問題。
使用@JsonBackReference標記在有多對一或者多對多關係的屬性上即可解決這個問題。
ps:
@JsonManagedReference:標記的屬性會被序列化,序列化時屬性默認都是會被序列化的。反序列(deserialization,即json數據轉換爲對象)時,如果沒有@JsonManagedReference,則不會自動注入@JsonBackReference標註的屬性。
@JsonIgnore:直接忽略某個屬性,以斷開無限遞歸,序列化或反序列化均忽略。當然如果標註在get、set方法中,則可以分開控制,序列化對應的是get方法,反序列化對應的是set方法。在父子關係中,當反序列化時,@JsonIgnore不會自動注入被忽略的屬性值(父或子),這是它跟@JsonBackReference和@JsonManagedReference最大的區別。
作者:宋欣聰
鏈接:https://www.jianshu.com/p/d9a78133c48f
來源:簡書
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