Task
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import javax.persistence.*;
import java.io.Serializable;
import java.util.Date;
import java.util.List;
/**
* Created by change.
* 任务
*/
@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 searchPoliceEntityList;
}
SearchPolice
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序列化的对象中存在双向引用会导致的无限递归(infinite recursion)问题。
使用@JsonBackReference标记在有多对一或者多对多关系的属性上即可解决这个问题。
ps:
@JsonManagedReference:标记的属性会被序列化,序列化时属性默认都是会被序列化的。反序列(deserialization,即json数据转换为对象)时,如果没有@JsonManagedReference,则不会自动注入@JsonBackReference标注的属性。
@JsonIgnore:直接忽略某个属性,以断开无限递归,序列化或反序列化均忽略。当然如果标注在get、set方法中,则可以分开控制,序列化对应的是get方法,反序列化对应的是set方法。在父子关系中,当反序列化时,@JsonIgnore不会自动注入被忽略的属性值(父或子),这是它跟@JsonBackReference和@JsonManagedReference最大的区别。