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。