通过 Postman 在 Springboot 中插入 parent 和 Child

Question

我想通过邮递员以一对多的关系使用 Spring Boot 保存记录及其子列表。子列表已保存，但它们不会自动获取父级的 ID。如何强制孩子在 Post Request In Postman 中自动获取父母的 id？

父类

package fdsa.edu.pnu.Model;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import javax.persistence.*;
import java.io.Serializable;
import java.util.List;

@AllArgsConstructor
@NoArgsConstructor
@Entity
@Data
@Table(name = "Concours")
public class Concours implements Serializable {
    @Column(name = "ID", nullable = false, length = 10)
    @Id
    @GeneratedValue(generator = "PNU_CONCOURS_ID_GENERATOR")
    @org.hibernate.annotations.GenericGenerator(name = "PNU_CONCOURS_ID_GENERATOR", strategy = "native")
    private Integer id;

    @Column(name = "DateDebut", nullable = true)
    @Temporal(TemporalType.DATE)
    private java.util.Date DateDebut;

    @Column(name = "DateFin", nullable = true)
    @Temporal(TemporalType.DATE)
    private java.util.Date DateFin;

    @Column(name = "Description", nullable = true, length = 255)
    private String description;
    @OneToMany(fetch = FetchType.EAGER, mappedBy = "concours",
            cascade = CascadeType.ALL,targetEntity = fdsa.edu.pnu.Model.PlannificationConcours.class)

    private List<PlannificationConcours> plannificationConcourses;


}

儿童班

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import javax.persistence.*;
import java.io.Serializable;

@Entity
@Data
@AllArgsConstructor
@NoArgsConstructor
@Table(name = "PlannificationConcours")
public class PlannificationConcours implements Serializable {

    @Column(name = "ID", nullable = false, length = 10)
    @Id
    @GeneratedValue(generator = "PNU_PLANNIFICATIONCONCOURS_ID_GENERATOR")
    @org.hibernate.annotations.GenericGenerator(name = "PNU_PLANNIFICATIONCONCOURS_ID_GENERATOR", strategy = "native")
    private int id;

    @ManyToOne(targetEntity = fdsa.edu.pnu.Model.Concours.class, fetch = FetchType.LAZY)
    @JoinColumns(value = {@JoinColumn(name = "ConcoursID", referencedColumnName = "ID")}, foreignKey = @ForeignKey(name = "ConcoursPlannificationConCours"))
    private Concours concours;

    @Column(name = "`Date`", nullable = true)
    @Temporal(TemporalType.DATE)
    private java.util.Date Date;

    @Column(name = "Quotation", nullable = true, length = 10)
    private double quotation;

    @Column(name = "NoteDePassage", nullable = true, length = 10)
    private double noteDePassage;
    
}```

Screen Shote where the Id of the parent is null
[![enter image description here][1]][1]


  [1]: https://i.stack.imgur.com/LlnhP.png

Answer 1

有两种方法可以到达它。这是最低限度的设置：

1. 单向

@Entity
@NoArgsConstructor
@Getter
@Setter
public class Concours {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @OneToMany(cascade = CascadeType.ALL)
    @JoinColumn(name = "concours_id") // this line will play the role that passes the parent's id to its children
    private List<PlannificationConcours> plannificationConcourses = new ArrayList<>();
}

@Entity
@NoArgsConstructor
@Getter
@Setter
public class PlannificationConcours {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
}

@Test
void saveConcours() {
    Concours concours = new Concours();
    concours.setPlannificationConcourses(List.of(new PlannificationConcours(), new PlannificationConcours()));
    this.concoursRepository.save(concours);
}

这就是传播父 ID 所需的全部内容。但是通过这种方式，孩子不会有对其父母的引用。

1. 双向

@Entity
@NoArgsConstructor
@Getter
public class Concours {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @OneToMany(mappedBy = "concours" ,cascade = CascadeType.ALL) // mappedBy will create a bidirectional relation for us
    private List<PlannificationConcours> plannificationConcourses = new ArrayList<>();

    public void addPlannificationConcours(PlannificationConcours child) {
        child.setConcours(this); // and don't forget to set the parent instance to the child
        this.plannificationConcourses.add(child);
    }
}

@Entity
@NoArgsConstructor
@Getter
@Setter
public class PlannificationConcours {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @ManyToOne
    private Concours concours;
}

@Test
void saveConcours() {
    Concours concours = new Concours();
    concours.addPlannificationConcours(new PlannificationConcours());
    concours.addPlannificationConcours(new PlannificationConcours());
    this.concoursRepository.save(concours);
}