创建新对象时外键为空

Question

我有两个实体类，具有双向的一对多关系的商品和类别。

下面是实体类，Category实体；

@Entity
@Data
@AllArgsConstructor
@Builder
public class Category implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.TABLE)
    private Long idCategory;

    private String categoryName;

    @OneToMany(mappedBy = "category", cascade = CascadeType.ALL)
    private List<Article> articles;
}

Article实体;

@Entity
public class Article implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long idArticle;

    private String designation;

    private BigDecimal prixUnitaire;

    private BigDecimal tauxTva;

    private BigDecimal prixUnitaireTTC;

    @Lob
    private byte[] photo;

    private boolean checked;

    @Transient
    private Long idOwner;

    @ManyToOne
    @JoinColumn(name = "idCategory")
    private Category category; 
}

我的休息控制器；

@PostMapping("/")
public ResponseEntity createArticle(@RequestBody Article article){
    if(article == null){
        return ResponseEntity.badRequest().body("cannot create article with empty fields");
    }

    return ResponseEntity.ok(articleRepository.save(article));
}

我通过邮递员发送的JSON数据：

{
    "designation" : "poupee",
    "prixUnitaire" : "10000",
    "tauxTva"   :"1",
    "prixUnitaireTTC" : "900",
    "category" : "1"
}

创建新对象时，我收到的ForeignKey为null。我有idCategory NULL

Answer 1

有两个问题；

1. 您正在category对象内发送article的怪异值。尝试发送类似的内容；

   {
       ...
       "category" : {
           "categoryName": "1"
       }
   }
   

   如果您打算通过categoryName传递"category": "1"

2. 从article的角度来看，缺少级联配置，因此，文章无法强制执行category的创建。要启用此功能，您需要更新与此关系；

   @ManyToOne(cascade = CascadeType.PERSIST)
   @JoinColumn(name = "idCategory")
   private Category category;